Sunday, November 27, 2016

More Minnie Monster photos with her custom look.

I took some photos of her in front of the factory.  I'm really liking the look.  Still haven't fitted a dash - the Acewell 6554 has arrived, but with no pressing need to get it fitted, she's once again back to waiting for the dreaded time.


Friday, November 18, 2016

Diagnosing bike not starting - switches and being inputs to the ecu

I had a fellow trailer a Monster S4 in this week because it wouldn't start.  With it on the side stand I turned on the key and the neutral light didn't come on, even though it was in neutral.  So I played around with the gear lever a bit, got the light on, hit the button and away it went.

The owner stood there with a rather dumbfounded look on his face, clearly having enjoyed the two hour drive leading up to looking like a dill.  But understanding why it worked for me and not him involved a concept that he had a bit of trouble understanding at first.

Back in the day, a neutral light was just a thing that told you the bike was in neutral, powered by a wire from the neutral switch.  Simple enough, and likewise obvious.  On most modern bikes though, it is primarily an input into the ecu.  The ecu uses it for the starter and sidestand logic circuits and also to turn the dash light on.  As such, if the dash light's not on, that's because the ecu doesn't know it's in neutral and therefore thinks it's in gear.  An obvious enough assumption based on the info provided.

When you press the start button (itself an input to the ecu) the ecu checks all the start/sidestand logic circuit inputs (neutral switch, clutch switch, sidestand switch) before deciding if it should activate the starter.  It does that by grounding the earth side of the starter solenoid.

Generally, the starter solenoid is activated under the following conditions:
  • In neutral
  • In gear with clutch disengaged (lever pulled in activating switch) and sidestand up
Although this Monster S4 (2002 MY) would start and run with the stand down and neutral light not on as long as the clutch lever was pulled in activating the clutch switch.  When you let the clutch lever out, it would stop.  Most things will stop as soon as you put them into gear if the engine is running and the stand down, or when you lower the stand with the engine running and in gear, even though the clutch lever is pulled in.

Anyway, digressing.  So, to expand on this, the reason this bike wouldn't start is because the neutral light wasn't on.  If I hadn't been able to get it to show, the next thing I would have done is pulled the clutch lever in (to the bars) and tried again.

Which leads to a possible total killer of starting desire - faulty neutral and clutch switches.  Then it definitely won't go, no matter what you try.

To get back to the fella with the perplexed look.  He said several times "but it was in neutral" to which I responded "was the light on?"  The answer to that was "no, but we know it was in neutral."  And that, folks, is the crux of the issue.  It doesn't matter what you think is happening, it matters what the ecu thinks is happening.

This is why my first response to people asking me questions about poor running injected bikes is "get it on a diagnostic tool and see what the ecu thinks is happening."  The ecu is running the show, so its opinion is the one you need to consult.  When you have a tool, it's a quick check.  Logged faults and plausibility of inputs is what you're looking at.  If it's all fine, move on to the next thing.  The diagnostic tool is probably not going to tell you what is wrong, but it will let you see what is right.

Monday, November 14, 2016

A makeover for Minnie Monster

I decided to do a 3 week rush job on Minnie for this year's Festival Of Italian Motorcycles, which was last Sunday.  I ran a thread on the forum about it, and am way too lazy to redo it here.  Maybe I'll do something here later - I still have to buy and fit a real dashboard.  The iPhone with speedo app isn't long term workable.

A makeover for Minnie Monster


Tuesday, October 11, 2016

Ducati ST3 front sprocket incorrect position take 2

See this post for more background: Ducati ST3 front sprocket

I had another ST3 in this week with the same issue, so took some more photos.

Spacers: ST3 (999, etc) on left, 1000SS on right.  19.7mm vs 14.2mm (or something like that, forgotten already).

Sprocket fitted with incorrect spacer.

Sprocket fitted with correct spacer.

Saturday, August 27, 2016

Part 2 of Dyno run comparison of things not the same - dunno, couldn't think of what to call it, it's a bit odd

I was curious to see how the torque curves of the std comp motors compared, so I made up a spreadsheet generated graph using exported data form the Dynojet dyno software to compare the old dyno to new dyno runs I did of the high comped 750.  Using the factor between those two runs (average of 0.882, 0.860 - 0.912) I calculated a std comp run for the big valved, 900 cam 750, albeit with std carbs for the new dyno.  I also took the dip out of the previous 750 run, just to make it look nicer.

The result is the graph below.  Black is 900 with FCR39, slip on muffers and open airbox lid.  Red is std comp 750 with jet kit, slip on muffers, open airbox lid, 900 cams and big valves.  Blue is high comp 750 with FCR39, slip on muffers, open airbox lid, 900 cams and big valves.  The yellow line is the comparison between the two std comp torque curves, as % difference of 750 from 900.  The 900 engine is 20% bigger than the 750, meaning an ideal situation should show this as a straight line at 20.  But with the reality of engines being engines, you don't get that.  Interesting that the centre part of the curve is just under 20% (17 - 19), which is as expected and it's always nice to see some correlation to the theory.  Once the 900 torque peaks just under 6,000 rpm the factor drops as the 750 both peaks later and doesn't suffer the same rate of drop off after the peak.

Thinking about it some more just now, the 750 was running the cam timing at 107 degree inlet centrelines, but the 900 was "as delivered".  Meaning not checked.  At a later date I did check the 900, and found both cams at 117 degree inlet centreline.  They were advanced to 107 degrees with a couple of 10 degree offset keys.  At 107 the 900's torque curve would drop away even quicker, possibly to less than the 750 at the end.

And there you go.  I found it somewhat interesting, hope you did too.

Tuesday, August 23, 2016

Dyno run comparison of things not the same - dunno, couldn't think of what to call it, it's a bit odd

I was going through some dyno runs yesterday looking for some 750 carb jetting info, and looking for a comparison when I came up with this one.

Looks like two runs with different jetting?  Not, as it happens.  The blue is a 900SS fitted with FCR39, open airbox lid, some sort of slip on muffler and no other mods.  The red is my hotted up 750 motor when fitted to Minnie.  Same cams as the 900, similar valve sizes, different FCR39 (you'd hope very much the same) and the exact same 152 main jets.  I have a bit of a running joke going with this pair of FCR 152 main jets.  I fit them to everything I do with FCR and see how they compare.  So far they've never kept a permanent gig.  Anyway, two things come to mind.

1/ Massive difference in fuelling where the only real difference is engine capacity, and therefore airspeed through the carbs.  The 750 has lower airflow for the same time frame (same cams), so less vacuum drop across the venturi (Bernoulli's equation) and therefore sucking out less fuel.

2/ Almost identical power curves run against road speed, with the red run stopping earlier appearing to be just a "as run" thing.  For the gearing to match it up this way is pretty neat, and shows that, on a short straight or in this gear at least (possibly 4th on both, 900 has two more to go) it'd be a fair fight to the next corner.

The next graph shows the power versus RPM, which shows them to be different.  As you would expect, the 900 will make more power at any given RPM under the power peak as it is larger, but also points out how good the 750 is comparatively.  

Comparatively is better shown in the torque curve, as below.  The 900 engine is 20% larger than the 750, so it should make 20% more torque all other things being equal.  In this case, the big variable is compression, as the difference in peak torque is only 8%.  The 900 has a bit over 9:1, the 750 allegedly around 12:1 (I never did check).  The runs I ran with the 750 as a std compression motor were done on a previous dyno which gave higher readings, so I don't have a std comp run that directly compares.  

Sunday, July 31, 2016

Rebuilding MV Agusta F4 mirror mount posts AKA when those stupid little knobs on the bottom break off and the bloody indicators won't work anymore.

I had an MV F4 come in with one of the front indicators not working unless the screw was almost loose because the stupid little cast on lugs had broken off the bottom of the mirror mount.  If you've worked on an F4 you've probably had it happen as you tighten the front fairing mount bolts.  Do them up tight on some - no problemo.  Gentle as can be on the next one - break.  They truly give me the hibbidyjibbidies.

On this occasion I thought I might do some thing about it.  I measured the knobs on the other side and they were 5mm diameter, so I drilled the mirror mount at the broken points, tapped some M5 threads into the holes, loctited some M5 screws in (long shank ones with the threaded section precut to the desired short length) and then cut the end off the screws so the desired shank length was left.  As per the photos below.  I was rather impressed with the results I must say, even if one is a bit angled.  It's all done freehand due to the impossibility of holding anything in a fixture.  Unless, of course, you'd made a custom fixture beforehand.  I didn't have that much time to hand.  And yes, the indicator now worked with the screw tight.

Clutch pressure plate bearings and the like

Third 748 story, this one a 1997 SP.  The owner was complaining of the clutch losing pressure over time.  Fluid level was ok, colour typically not, no obvious leaks, aftermarket slave.

I removed the slave to check for the rubber bellows (there, but fitted the wrong way around), but found a short section of pushrod stuck in the end of it.  There are two o-rings on the pushrod that goes across the engine, just inside the cases on the slave side.  On the later 3 phase alternator bikes, a pushrod broken at one of the o-ring grooves is a very good indicator of the flywheel nut being loose.  But this was an older single phase alternator bike, and it didn't sound like it had a loose nut to me.

But I thought it might be more likely to have a seized bearing in the pressure plate, which it did.  Totally seized.  This is one of those issues that suddenly started appearing after many years of none at all.  I see quite a few 2000> era bikes with the bearing seized (or at least rough), but not older ones.  Late model bikes have a pin through the pushrod at the LH end that locates in the slave cylinder boss and stops the pushrod spinning, which is a typically involved solution to a seemingly simple issue.

The bearing in the pressure plate is a normal ball bearing.  I always figured it was used somewhat poorly, given it's not specifically a thrust bearing but someone who knows bearings told me once that it was probably just fine.  Maybe, like the 2002 ish onwards front wheel bearings, it's a bearing quality issue.  Although on this bike the pressure plate was aftermarket, so a non Ducati bearing.  Possibly worse.

As the pushrod had been spinning, it was quite stuck in the slave piston and had probably damaged the slave bore.  The easiest solution was to replace the pushrod with the later, 2001> longer part and fit a new aftermarket slave, in this case an Oberon as they are both well priced and, from my experience, well made.

It also had the usual wear at the centre of the hub, where the big steel washer slowly eats its way back into the hub.  I see a lot of this, and if the wear is not great you can add another washer to take up the clearance.  Clearance here allows the hub outer section - the splined aluminium piece - to move in and out on the cush drive rubbers that sit over the steel inner section.  This translates as excessive freeplay at the lever, as the movement of the hub moves the pack and pressure plate with the hub without lifting the pressure plate off the pack.  As an aside, I have seen (and indeed fitted) up to 4 washers here to take up the wear when the budget doesn't extend to a new hub.  It's quite amazing how thin the hub can get and not fail.

I found a photo of the one that needed 4 washers.  You can also see the wear on the pushrod - the stepped section runs in the needle roller bearing just inside the end of the input shaft.  It's not meant to have a step.

Saturday, July 30, 2016

Odd alternator cover leaks

I'm on a roll now, so possibly the second in a three part 748 tale of woe.

I had another 748 in recently, just purchased sight unseen from interstate from a shop I believe.  Allegedly a low km (3,500 miles) import, clearly bought from a bloke with a very long nose and charred pants.  It's really sad to see people get ripped off like this.

Apart from a couple of basic and unmissable compliance issues - LH drive headlight and non approved braided brake hoses - it had undersize front brake discs, front brake and neutral lights not working, steering stop broken off the frame, rusty steering head bearings and more.  Minor detail stuff too, like normal screws holding the mirrors on instead of the brass, breakaway head screws, screws holding the seat on instead of the plastic pins and rubber keeper and no tank pin grommet in the front of the airbox, which was contributing to the steering damper taking the paint of the front of the tank on the RH side.  Again (self righteous wanker statement time) just work done by someone who doesn't know the bikes or what causes issues.  Some of it well intentioned, some just sloppy.

I worked out the neutral light issue was that the dash / front section of wiring loom was for a late style single wire neutral switch, where the switch completes an earth circuit through the engine, while the neutral switch and rear section of loom was the older two wire 12V continuity switch style.  To make the light work I left the switch wire from the dash globe connected, and made a little wire to go from battery negative to the other (originally 12V power) switch wire to earth out the circuit and bring the light on.  Simple, but never going to work as was.

Another was oil leaks from the alternator cover.  Usually they leak from the clutch pushrod hole, caused by the clutch slave (which is bolted to the cover) trying to pull the cover off the crankcases every time you pull the clutch lever and stressing the goop over time until it no longer seals.  Often the cover screw behind the slave is loose too, in this case it might have been too long and not bottomed. Anyway, I pulled the cover, looked for other obvious issues, cleaned, gooped and refitted.  I also replaced the rotation sensor o-ring (old two screw pickup, original o-ring now NLA) and applied some more goop, which I really don't like doing when o-rings are involved unless I really have to.

Then I went for a ride and parked it to see what it dropped and to my profound dismay it started immediately.  At which point the source of the leaks became a little more apparent.  Certainly nothing I've ever seen before either.  The video shows oil bubbling out from under some corroded paint near the top of the cover, around the unused boss originally for the crank sensor on P8 ecu models.

It had more leaks, under the DUCATI logo at the bottom of the cover and a couple up at the front of the water pump below the rotation sensor.  Again, just oil coming through.  I don't know if it's just porous or if it is residual crash damage.  While trying to find a replacement cover I spoke to Shaun at D Moto and he said in his DDT days that they used to see the race bike covers do similar things after crashes.  No obvious marks or damage on the outside or inside, just leaking.

Steel fuel tanks and rust - the sort that makes holes and creates much agro

I had a 748 in recently - 20,000km, overall quite clean, purchased a couple of years ago out of Queensland.  It had some marks on the engine cases showing some sort of "liquid from above" staining, and when I pulled the tank there were a couple of small areas of paint bubbling with a wet look about them (never good).  Removing the pump assembly showed the extent of internal rust.  Photos show some of the tale.  The crud around the fuel pump pickup was quite amazing.  The rust holes shown were exposed using a piece of Scotchbrite only, there was no real effort involved.  It's amazing to think it wasn't just pouring out.  I was discussing this with Brad at BikeCraft and he said he has had customers come in to him with tales of no leaks until it dumped a whole tank in seconds from this sort of rust damage.

If your bike has a steel tank, it's important to look inside it at regular intervals.  Make sure the cap recess drain is clear, so any water that sits in the cap recess will drain out, not run into the tank the next time the cap is opened.  Add something to remove water occasionally.  Every time I service a bike I add about 100ml of injector cleaner.  I use Wurth brand cleaner, I think what I get is the imported stuff that you can't buy retail afaik.    It's great stuff for cleaning injectors - I've had to reset idle mixtures after road tests sometimes just due to it doing it's job - but it's also good for removing water from the tank.  Metho also will do the water removal job.

Even plastic tanks can benefit.  Sometimes you can get a jelly sort of stuff build up in them, or you get the likes of the Cagiva Raptor, where its plastic tank has a bolt in fuel pump assembly with exposed steel fuel pump wiring.  In a triumphant masterstroke of engineering design, those terminals sit at the lowest point of the tank.  Right where the water collects.  Genius.  Luckily you can get the complete plate assembly from Suzuki as a TL1000R part - at around $800 (from memory) it's about half the price of the probably now non existant Cagiva part.

Another thing I see with plastic tanks is their cap recess drains blocking at the little screw in aluminium barbs in the bottoms of the tanks.  Often the rubber hose routing after the barb is such that there is an upward run causing water to collect in the barb.  They just fill with white corrosion, which can go surprisingly hard.  I find the easiest way to clear them is to run a 2.5mm drill through them, which also illustrates how small and easily blocked the hole is.  Best to remove them before you go drilling into them while they're mounted in a plastic tank, but then again I've had a few break off before coming out.  I now keep a couple on the shelf.  Any of the late model bikes with plastic tanks can suffer from this, including Aprilia and Moto Guzzi.

Ducati 2V timing belt adjuster bearings

I had an M1100 in recently (same one I pushed some time ago) to follow up on a poor starting issue.  I see a few of these in for valve clearance services (first clearance service, or first by me if I can say that without sounding like a self righteous wanker) where the owner will comment, often once finished, that the bike can be hard to start.  Or they'll ask me "did you have any trouble starting it?"  Usually I respond with a bit of a blank look and "no, fired right up".  But when doing the clearances I would have found lots of closing clearance and no opening clearance on the exhausts.  After setting the clearances the starting issues seem to go away, so it's the next thing I would normally check after cranking compression, leakdown and fuel pressure.  In that order because it's the most time consuming.

On this particular bike I found one exhaust opener with zero clearance, and the expected lots of closing clearance.  When I say lots of closing clearance I mean in the region of 0.15mm.  Many will recognise that as being within the Ducati specified range of 0.00 - 0.20mm.  In my experience, 0.20mm will cause you all sorts of idle and low speed issues.

Not that it made any difference to this bike.  Still not a happy starter, taking 3 or 4 cranking cycles to fire and run.  I did notice, when doing the clearances, that it was very, very hard to turn the engine backwards with the rear wheel.  Fine going forward, very hard backwards.  The difference here is that turning the rear wheel in the direction of normal rotation just turns the gearbox and crank.  Going backwards engages the starter motor system through the starter clutch, and although the drive ratio means the starter spins much faster than the crank, it still should turn rather easily.  I have seen a few idler gears weld themselves to their stud over the years, and I'm curious about this one.  It will have a Motolectric starter lead kit fitted next, but I get the feeling I'll be pulling the alt cover following that.

Anyway, none of that is why I'm writing this.  Today's rambling is about what I found when I pulled the belts.  This bike has done 26,000km, and had a 24,000km (meant to be a valve clearance) service done within the last year I believe.  I always spin the belt adjuster and idler bearings to see how they feel, and on this one both adjusters felt a little rough.  A little rough means they get replaced.  The horizontal idler was making a very dry noise, so I added it to the list, then looked at the vertical idler.

It was completely seized, and you can see how hot it has been from the belt rubbing over it.  I have seen a few M696 with this bearing failing or failed on the vertical cylinder, all around 36,000km.  But not one this bad.  So it got all idler and adjuster bearings (supplied as complete assemblies only these days from Ducati) and a pair of belts.

Something to keep an eye on.

Monday, July 11, 2016

Another dyno debacle with Minnie the 400 - Ducati Monster 400 dyno runs

So, I had some time today to return to Dynobike with Minnie.  Last time, some weird stuff went down with dyno interference.  This time, I had some different Kokusan ignition units fitted and took along a couple of Ignitechs - my old one with the last curve I ran, and a new one just in case.  I checked them all with the timing light before hand and all the units (2 pairs of original Kokusan and 2 Ignitechs) had the same idle and full advance, with my old Ignitech taking longer to get there.

My old Ignitech and the Exactfit ignition coils have been on this bike with the 750 engine on this dyno before, so I figured that, if required, that set up should ultimately rule out any issues.

Bup bow.  Wrong again.  I forgot the Ignitechs would have had the rev limit set at a normal-ish 9,000 rpm.  The 400 goes to 11.  Plus they seemed to have a misfire of sorts.

Anyway, eventually some runs without rpm or air/fuel (the bike shuts both of those dyno functions down) were made, comparing cam timing settings and std vs the all conquering Megacycle mufflers.  As below.  46 mph = 5,500 rpm.  80 mph = 9,500 rpm, 93 mph = 11,000 rpm.  Ish.

Megacycle mufflers fitted.  Comparison of 108 degree inlet centreline cam timing in red, 120 degree cam timing in blue.

Same as above, but with std mufflers.  The interesting thing here is is the angle of the power curve right at the end of the 120 degree run.  You could hear it on the dyno too.

Clearly, no matter what else you're running, 108 degree inlet centreline is the go.  I had the pullies drilled for 112 and 116 too, but I wasn't going to waste anymore time with what seemed like pointless experimentation.

Next, std mufflers in blue versus Megacycle in red with cam timing at 108 degrees.  Odd linear straight line bit between 25 and 45 mph, hole between 50 and 60 mph.  

With the cam timing at 120 degrees, it's pretty much the same thing with a bit less everywhere.

For a bit of a starting point to final comparison, std mufflers and 120 degree cam timing in blue, Megacycle and 108 degree in red.  Up to 15% better in places, but then again, 15% of not much is quite a bit less.  The red curve power goes flat at 9,000 rpm and peaks around 9,500 rpm, so you can shift earlier too.

Finally, a sample of the frustration.  Blue is the run from the first session two and a half months ago.  Red is the same set up from today's session.  The only change is the ignition control units, one pair of original Kokusan units replaced with another pair.  But even more confusing is the green curve.  That's from today as well, with the Ignitech unit fitted (the new one from memory).  It had a bit of a misfire through the rpm range, but it's about 20% stronger than the runs with the original control units that followed minutes later.  If someone can explain that to me I'd be very happy.

Lastly, what timing belts look like going to 11,000 rpm.

Friday, April 29, 2016

Danmoto SS-00001 Harley Davidson mufflers fitted to the Monster

I finally made a real effort to get these fitted.  I'd had a few looks at brackets, but then decided to do what I'm usually very reluctant to do, and go the cut.  I should do it more often, it was a rather liberating feeling.  I cut off the rear mounts, leaving the front ones for a cleaner look.  Then, using the steel pieces that come with the mufflers, I cut and drilled as required to make them work as brackets.  Followed by a quick bead blast, etch prime and paint, they were ready to go.  You can hardly see them in the photos, which is a good thing I guess.

You can see the offset mounts in the bottom two photos, one of the reasons it took me so long to make them work.  Like Hunnybunny, I have a thing for symmetry.  And, obviously, it's not Minnie.  This 900 was on the bench for other work, and I had tried previously fitting the Danmoto Jisu muffler set I have to it, ending in dismal failure.  The aluminium swingarm this M900S (98 I think) has is 15mm wider overall than the M600 steel swingarm, and I just couldn't get the Jisu mufflers to go anywhere near clearing.

There's a video at the end.  They're louder in real life (or is my laptop just too quiet, maybe it's a conceptual thing).  After riding and standing next to it, I'd put them at the higher end of the open muffler range I would think.

It's good to see them fitted.  It was a fair bit of agro to get this far, especially getting the muffler pipes made up.  Maybe only a bend and two flares, but getting people to understand what you want can be hard some times.

And then, of course, I started thinking about maybe using some much shorter muffler pipes and mounting the mufflers further forward.  Next time.

It does indeed go to 11

I took Minnie down to Dynobike this week after I had some time to fill in due to a no show, which went rather unexpectedly very badly.

It appears Minnie is inhabited by some sort of poltergeist, the kind that enjoys messing with dyno control systems.  The inductive pick up, used to read engine speed, was registering (albeit not accurately enough to be useful) that the engine was running while being a metre from the bike.  We tried some non rpm runs, but the air/fuel readings were going nuts and occasionally the screens would drop out.  And then the dyno decided it was too cold.

We did get a couple of "power vs rear wheel speed" runs, but because Minnie doesn't have the tacho fitted, I really don't know how many rpm she was doing.  I did see that Dave had already had a couple of M400 in.  One of them, labelled as a 2003 so it may have been an ie, put down 37hp at 11,000 rpm.  I had assumed that the claim of max power at 11,000 rpm was rubbish, but it would seem I was wrong.  Again.

So, first dyno chart for Minnie as a 400: 41hp.  I'm looking forward to getting the tacho fitted so I can watch as I ride.  I'm pretty sure that I haven't gone over 7 or so as yet.

As an indicator, this is the 2003 model with rpm.

Sunday, March 20, 2016

Some different Danmoto mufflers

While cruising the Danmoto site one day I came across some Harley mufflers that I really liked the look of.  Plus they were very cheap (at least to buy, the adapting is where the money goes).  Available in a few variations, I chose the ones that I thought would look the best.  I tried to persuade them to make me some pipes to fit them to the Monster headers, as the muffler inlet is 45mm instead of the usual 50mm, but without any luck.  I found a local shop who bent some up, and after a couple of tries I got the angle right.

I haven't got to make any mount plates yet, the mounts welded to the mufflers are the same, but offset meaning one is higher than middle and the other lower in the orientation I've got them, and so will require two different mount plates.  On the Harley I think the mounts go to the bottom.  Dan did offer to take these back and make me a set with the mounts welded to the mufflers where ever I wanted them, but I haven't got that far yet.

Maybe they're a bit skinny for the Monster, but they'd probably look a lot better without the std footrest mounts.  Running them at the same angle as the lower footrest bar as shown below (about 30 degrees from horizontal) has them a fair way below the bracket.  The bottom of the plastic side cover is 40 degrees, and they look a little better at that angle.  Who knows where they'll end up.

More Minnie fun

I rode Minnie out to see Rob at Guzzi Spares the other day.  I figured the 35 or so km to Cranbourne would be a good shakedown (if indeed shaking was required) and otherwise close enough to good help at either end to be safe.  I hadn't been to see Rob's new workshop before, and, feeling like a slack friend, took the chance when I had it.

However, she has been running very well.  I  currently don't have a tacho fitted, but there seems to be a bit of a harsher patch around 4,500 rpm I'm guessing.  Either side of that and it's good.

I did check the idle mixture again after the ride.  She's done 100km now since the recommission, and I had put some of the Wurth fuel system cleaner (it's really good gear) in the tank to see if there was anything in the carbs from the 4 or 5 years of sitting on the shelf.  When I first got her running the screws were either side of 4 turns out for 5 ish % CO.  Now they're back to either side of 2 turns out, where I'd expect them to be for a 400.  She still starts and revs from cold without choke, which seems a bit unrealistic to me.  But I did go through the carbs (original M600 from 1997, which are the same as the 400 from 99 onwards) and all jetting is spec.

The gearing is still making me laugh, but it has also given me a bit more perspective on ratio spread.  Maybe it's just the little engine thing amplifying stuff too.  Parts of the freeway that used to be gentle rises are now hills.  And, once climbed, the speed increase on the downhill is really noticeable.

The table below shows the gearing, compared to the other boxes.  First is very short, and the smallest gap between gears is 13% - the very noticeable difference between 5th and 6th.  I was thinking of modifying the "800" box I have (actually out of a 696) with a change to one of the 6th gears to make it 11 or 12% gap from 5th as opposed to the 8% it is std, but now I'm not so sure it'd be such a good idea.  Then again, the 900 wide ratio box is 12% 5th to 6th and it feels just fine, so maybe all I need is some more cubes.

Thursday, March 10, 2016

Setting float level on Mikuni BDST38 carbs from Ducati Supersport and Monster

Well, maybe not so much setting as checking.  I had someone ask me recently about float level, and the way that I've always checked them is as below.  I thought I'd posted a photo of this before, but can't find it anywhere now.  So I'll do it again.

Traditionally, checking a float level is a measurement done with (usually) the carb off the bike and orientated so that the float sits gently on its seat.  Dellortos are done this way, but there's no official float level spec given for the Mikuni in any Ducati manuals.

The way I was told to do it (not sure who by now) was to put a clear hose onto the float bowl drain outlet and hold that hose up the side of the carb to where the boss cast into the body is.  On the LH side as shown by the yellow arrow in the photo below, the boss has a little nipple.  On the RH side there is a dimple.  You need to get all the air out of the little piece of tubing, and you'll often see a little air pocket just next to the drain outlet.  The easiest way to achieve that is to remove the tube from the drain outlet with the drain screw open so that some fuel spills out.  Without doing that, I have found the reading is always inaccurate.

What you are looking for is shown below.  I don't think I've ever checked one that has been wrong.  Certainly not one that hasn't been played with anyway.  If someone has been in there trying to make it right it's usually not.

You do need to make sure the bike is vertical though.  if it's tilting even a little you'll get high and low readings side to side.

The annoying part is that you need to remember to do this before you pull it apart.

Saturday, February 27, 2016

Ducati timing belt replacement, factory tool and cam timing ramblings

I did a 40k service on a 2003 ST4S last week, and given there was a bit of variation in the cranking comp I thought I'd check the cam timing.  With a new pair of Exactfit timing belts tensioned to 11.5 on the old gauge the timing was O: 124/105 and V: 120/108.  The 2003 model year was the first of the Desmoquattro with the adjustable cam pullies that had been fitted to the 2V motors from 2001.  In my experience, the accuracy of the "as delivered" cam timing on these engines is much worse than the old solid pulley engines.  I adjusted the timing to 113/110, advancing all cams between 2 and 11 degrees.

As an aside, when they went to the adjustable pullies on these motors (S4, ST4, S4R, ST4S) they changed the cam numbers (the # stamped on the cam).  I expect this is because the alignment marks on the heads changed to allow for the cam locking tools, and given the pullies were the same as the 2V parts where the marks hadn't changed, they had to change the keyway positions.  Same profiles.

My inspiration for posting this came from a thread I had previously missed on Ducati MS - ST4S running a little strange - about someone who had the belts changed on one of these engines using the full cam and crank locking procedure.  It's quite an interesting thread in terms of both what actually happened and the usual rampant speculation entered into between problem and fix.  I didn't really buy the official explanation either, but reading it again it reads like the shop initially didn't have the right tools, but did it anyway or that the fix was to ignore the tools and set the cam timing as I did above.  Either way, it backs up my view that using the factory tools and method has the potential for a result without any positive apart from being "how it was" and for a whole load of negative.  

There was another thread on Ducati MS I replied to that I outlined my opposition to using the cam and crank locking method for belt changes, so I thought I'd cut and paste that here too.  Only my opinion, of course.

i have never used the factory method of locking crank and cams, for a few reasons i'll try to outline as coherently as possible. and i'll try to cover other related bits as well.

1/ when you lock the cams and crank, the tools used, in combination with the tools locations in the pullies, determine the timing. from memory, the crank locking tool is pretty good. but the cam locking tools and positions thereof were always the issue. when i did some factory training in 2002, the training dept had just set up some 998s for an italian race series. they told us that the factory tools set all the 998s cams about 6 degrees retarded. when we did the timing on them, as a very round rule we used to advance the inlets about 10 degrees and leave the exhausts much where they were, giving the 105/109 we used ish.

i don't think i ever tried setting any of the 2v or 4v desmoquattro motors with the factory tools. ex factory the 800 motors had 5 to 8 degrees retard. s4r/st4s had similar inlet cam inaccuracy, much worse than the fixed pulley st4s motors. from memory the 900 motor was pretty good.

the tools required started to grow with the models, 2005 saw a big cam 749S specific tool with the revised stalling fix timing set in, etc. they were pretty accurate from memory.

so cam locking tool wise, it was a bit of a clustercuss accuracy wise. if the tools gave the same result as the production line, that's fine. inaccurate is ok if it is the same as before. make it worse though and it's an issue. the only way to know the timing is to check and set. most people don't expect to be paying for that as part of a service.

2/ when you have locked everything, you loosen the pulley half screws so the cam outers move. but you have to loosen them a bit to allow them to move freely with belts fitted. when you loosen those screws, it allows the pullies to cock due to the belt tension. so when you tighten them again, the pullies pull up squarely and this increases the belt tension. how much will vary, but following the factory method will introduce error. i don't like that, as it seems kind of pointless to me.

you could fit the belts, tension each correctly with each cylinder at tdc firing individually, then do the cam locking thing. still seems like a great waste of time to me, as you're doing nothing to make the timing more accurate than the factory did. this is the main reason i don't do anything that the factory recommends locking and setting wise. no point imo.

i don't know of any shops that do the factory method. we certainly didn't as an authorised dealership. the importer also never made any point of recommending it. i think, as a service procedure, it's a total waste of time. i might have said that already.

3/ some of the later cams - testa, testa evo, some 659/696/796/1100 - have no timing marks. with experience you can usually know where to set them without tools (except some of the 2v, 696 maybe). or you just mark them in a way that makes sense to you and use those marks to reset. it's pretty easily done. and that's one of the things that's important here - you choose a convention and stick to it and then it works just fine. remove the old belts, fit the new ones, tension and away you go.

4/ the belts themselves can also have an influence. the exactfit belts are a little shorter than the oem belts, due to them being more accurate to the sae tooth form. i think i have back to backed new 900 and 999 belts. the exactfit belts generally advanced the cams 2 degrees.

5/ that's all i can think of, think i might have had something else to say, but i've forgotten now.

My ST3 cam timing and front sprocket post from July 2015 showed other weirdness that can get you too, so possibilities abound for screwing it up no matter how good your intentions are.  The good ol' things you don't know you don't know.

Often you see owners replying to these sort of threads with comments along the line of "I'd expect a dealer to do it by the book".  But the reality is, in some situations, the best thing you can do with the book is hit the owner with it.