Saturday, November 18, 2017

Sunday, November 12, 2017

My revised muffler baffle for Minnie

This is the baffle I knocked up prior to riding to the FOIM.  I realised I was later than I expected at that point, so it was quick.  Not pretty, but very effective as it happens.  Many years ago Mark Harris who was Madaz at that time told me a baffle needs to fully obstruct the linear flow of the gas to really work, but without that obstruction being overly restrictive as such.  The previous one was a shorter tube much the same size with an open end, like a Staintune baffle would be.  It really didn't make that much difference.

Not sure how this will work on the dyno.  Not sure that I want or care to find out.

An end for Minnie's makeover

At the start of the week I had a "to do" list for Minnie to get her ready for the Festival Of Italian Motorcycles today.

"Front brake work?" at the top literally meant "does the front brake work?  With the second front disc adding a corresponding caliper, the demand for front brake fluid displacement increased by 100%.  The original single disc front master cylinder is 13mm, the original dual disc front master is either 15 or 16mm, depending on model.  My 851 had a 15mm master originally, which I replaced with a 16mm (from my Sport 1100i after I crashed it I think).  I was curious to know how it would work with the 13mm, as I'd never tried it before.  My feeling was it would just have a lot of travel and probably some good feel.  But the reality was you could pull the lever back into the bars with little discernable increase in pressure.  Like it had air in it - I spent ages bleeding it thinking I'd screwed that up somehow.  Whereas on the road it gave a lot of travel before it finally started to stop, without a lot of feel as to when it was going to stop.  So, curiosity answered, larger front master needed.  That was Monday's decision.

The 15mm master is 31% bigger, the 16mm 50% bigger.  I went looking for my 15, but couldn't find it.  I figured the best way to find it was to buy and fit a new 16mm master (it worked).  Because the look for this bike is the "coffin" style  masters, I had to buy a new one as the Sport 1100i 16mm now on the 851 is a remote reservoir style.  The new one turned out to be the new style with the larger fluid reservoir, meaning the lovely Chinese billet reservoir caps I'd bought the week before didn't fit anymore.  Great.  And the pivot pin, which is cad pacified (gold zinc) plated on the originals, is now silver and I've spent a heap getting all the fasteners replated so I had to refit the "not so shiny like the rest of the fasteners" original.  Hmmmmmm.  Did have a nice new lever though.

But, it worked.  Funny how a 100% increase in fluid demand is happily dealt with by a 50% increase in delivery.  The very cool floating cast iron discs don't like sintered pads, so I went through my stash of old single pin original pads and found a couple of pairs that were bead blasted and fitted.  Stops better than it used to with the single disc, but with the organic style pads you just don't get that initial bite that I do enjoy so much.  Maybe some new Ferodo Platinums will help.  More money.

So that was #1 ticked off the list.

The speed sensor for the Acewell was the next issue.   With the caliper adapters there wasn't anywhere to fit a little bracket like I had previously.  I liked the little bracket, as it is a serviceable solution (as in you can remove and refit).  My mounting as below is not - double sided taping it to the bottom of the fork leg.  The sort of thing that customers do that annoys me.  I drilled and tapped a thread into the disc carrier and fitted the little magnet and away we went.  Easy.  Compared to the 120/70-17 circumference of 1860mm, the 130/60-16 measured at 1735mm.  But after riding it around with the iPhone zip tied to the handlebar clamp and the speedo app running, I increased the setting to 1760mm (1.5%) to bring the speedo in on the underside of accurate.  #2.

The tacho drive is due to this being an SS engine, which has a cable drive tacho.  I do have a Monster blanking plug somewhere (at least one in an engine), but laziness had kept me from moving it any closer to this engine.  I found a little blue rubber cap that fitted just fine, and it has resisted bailing for quite some time now.  But, I figured I'd make it a little nicer and I like machining stuff, so turned up a little cap and screwed it on with an old cable collar (I always cut them off old cables just in case).

The rocker covers were looking a bit crappy, but I didn't have any paint close to hand that I thought might be a good fit.  Well, I have some gold that is possibly a good match for the Paso rockers covers that I always liked, but didn't think it'd match the rest of the bike.  I didn't want anything bright, but didn't have any shades of real grey so I gave them a coat of cold gal.  With the rocker covers bead blasted and heated with the heat gun the cold gal dried at it hit them, the finish is rather matt and coarse and lighter than I expected, but it's there and that gets it ticked off the list.

This engine has the D on the timing belt covers and the DUCATI on the alternator and clutch covers, so I scraped, rubbed and polished the paint off.  I thought it was a nice little detail.

I needed a new clutch lever and reservoir cap (to match the new original on the brake master) and the master body had a fair bit of scraping along the road damage near the pivot.  I figured the best solution was a complete new master.  Easy.

I was looking for something to fashion a brake line bracket from to hold the front brake hose at the lower triple.  I usually find old horn mounts are good for this sort of stuff, and I stumbled across a nice gold zinc one.  Just lovely.  A quick bend and on.  Another one down.

The last point on the list - frame bolt caps - had me loking for the rubber caps that go into the tubes for the engine/frame bolts, and it took me to a tub that I thought (possibly correctly) contained mostly parts of the disassembled 400SS.  And in that tub, I found the 15mm front brake master cylinder.  Bugger.

At least I know where it is, so now I can lose it again for the next time I want to use it.

To make the inside of the muffler end cap a little less obvious I tried to clean up the inside with some scotchbrite (which didn't work as hoped polish wise), then ran some masking tape around the inside of the outer and the machined end cap.  I had machined the end cap prior to giving it to Ken when he made the muffler so I could fit a baffle as used in the last muffler.  It didn't make a lot of difference sound wise, so I made another with a smaller and longer internal tube and then folded a piece of sheet metal into a u shape and welded it on.  Suitably low rent, and effective I must say.  I don't really know if it's that loud, but the high outlet certainly gets into my helmet.

And today at the FOIM, after a lot of them had left.  I think it might be finished at this point.  

Now I can pull it apart again.

Tuesday, November 7, 2017

Ducati 2V cam profile comparisons

I made up a fairly basic jig to hold a 2V head and a couple of dial gauges so I could plot out some 2V cam profiles.  I used a spare 400 head I have which is a 3 bearing style head, as opposed to the later 620/695/800 2 bearing head.  

For test samples I had the following, with their Ducati specs:

I borrowed some P (Montjuich, Laguna Seca, Santamonica) and 8J (900ie) from Chris Boucher and Peter Nuss on the TT1/F1 forum, so a big thank you to them.  The 2S 620 cams had been modified to go into the 3 bearing head as used in the previous installment of the Minnie the 400 debacle.  I didn't have any 800 cams (3X and 3U?), and they wouldn't fit into these heads anyway.

The rig was very much analogue.  I did look at some digital dial gauges with outputs, but the cost put me off that pretty quickly.  I did the testing at nights, which involved me sitting down, reading the degree wheel and dial gauges every two degrees of cam rotation and typing that into my spreadsheet. It started out as fun, but after the first couple it got a bit dreary, and by the last two was just downright tedious.  I was very glad to see the end of the job.

Because I was reading the degree wheel every two degrees, I have cam lift values corresponding to every four degrees of crank rotation.  I wasn't going to take readings every degree of the degree wheel - I would have lost my mind.

The result is the following.

Separating the Pantah head cams out (vertical cylinder carb at rear of head), the following has the Pantah (labelled PH in the chart), F1 and P cams.  The F1 cam is the same profile at the R, but ground 8 or so degrees advanced.  I had a set at one time that had OE and MV stamped on them.  To accommodate the higher inlet valve lift at overlap (inlet valve opening) that advance brings, the F1 pistons have comparatively deeper valve reliefs than the later 750 pistons.  From memory they have higher crowns too for more compression.  Although both would be less than that required for the P cams fitted to the Montjuich, Laguna Seca and Santamonica models.

Immediately obvious is the extra duration and valve lift of the P cam.  It's what I would call old school, and what would have been referred to back in the day as "race", or even "full race" if you were going for effect.  Cue the oohs and aahs and air sucked through teeth.  As with most of the old school race stuff, it's kind of crappy now that good ports and cams are well understood.  The greatly increased valve lift at overlap (exhaust closing, inlet opening) is what requires far deeper valve reliefs.

I don't understand what it is about the F1 cam that made them want to use that over the original Pantah cam.  Similar 1mm lift duration and less lift doesn't really seem like an advancement to me.  Bruce Meyers told me the Pantah cams were better in his experience, and now I can see visually that I would expect that to be the case.

Next the "Paso" style engines, which simply means vertical head rotated with inlet at the front.  Although I think it was the prototype Elefant that first displayed the reversed head in 1983.  Anyway, they started out with the R cam, then with the 906 came the HT cam, the HZ in the ST2 in 1997 and the 8J in the 900SSie in 1998.  Also available for them were the Vee Two cams, the 210 grind being the same as the DP 06090 and Gia.Co.Moto GM09 and the 212 grind.

The 2S grind, which was fitted to the new 620 engine of 2002, was the first of the two bearing cam fitments.  This cam was only fitted to the 620.  The 800 also used the two bearing cam with similar duration to the R cam, but with 1.5 - 1.8mm more lift.  This was marked 3X (also 3U?).  It specs like quite a good cam and worked well in the 800, which made 900 ish hp with the 900 size valves, but 15 or so degrees less duration.  This cam was then used in the M695 and M400ie.

First up, R vs 2S.

Dyno comparison from Minnie the 400.  Red is R @ 108 inlet centreline, blue 2S @ 112 inlet centreline and green 2S @ 107 inlet centreline.

R versus HT.  The R cam was also used in the W head M900 engines and the Cagiva Elefants and Gran Canyons.

Dyno comaprison from my M750 with ported, big valve heads.  I later realised that I had taken some ignition advance out of it which did hurt the power at the top end.  But I assume both curves would have been similarly affected.  It was nowhere near as much change as I expected (or had hoped).

This is a 750SSie I did prior to my M750.  Red is R, blue is HT.  I did quite a bit of tuning to it with the HT cams, both fuel and ignition advance.

R vs 8J

Dyno comparison from a Cagiva Gran Canyon, which is a 900ie engine with the W heads - R cams and 41/35mm valves.  We fitted 8J cams to it set to 106 degrees inlet centreline in the hope it would make some more power.  Not enough, as it turned out.  It was still 8 or so down on the 900SSie engine with 43/38mm valve V heads.

The 900 cams - HT, HZ (ST2) and 8J.  The ST2 cam has gained a reputation for being the best, and of working well in a 900 carb engine, but I've never seen any dyno proof of that.

There's really not a great deal of difference between the 8J and HZ.  The 8J inlet peaks a little earlier and longer.  If you compare the area under the curves, again there's little difference.  

If we add the two Vee Two cams to the above, you get a somewhat confusing graph, but the two Vee Two cams stand out for their similar exhaust profiles to the HZ and 8J and their similar inlet profiles to each other.  The 210 definitely works at a lower rpm range than the 212.  Both of these cams don't match their specs, as below:

HT vs 210.  The inlet duration is not much different, and the 210 certainly has a lot more area under both curves.  But the lesser exhaust duration is what hurts it at the top end.

Dyno comparison of a 900SS, fitted with Omrae slip on mufflers and otherwise std.  Well, I believe the after run is the first of the tuning runs.  Red is HT, blue 210.  It certainly picked up the midrange, which is what the long manifold carb motors are all about.

That's it for direct comparisons.  I'll finish by quoting Bruce Meyers, who has a lot of experience playing with these engines.  He posted this in relation to hotting up the 800 engines on a forum some years ago, and I think it's a good piece for reference:

--900SS Carby cams: give a nice increase from 4000 rpm up with avg +4 rwhp over stock cam.

--ST2 cams: Net a bit more on top end rwhp with no loss of midrange.

--900SSie cams: Net alot more on top, maybe 2-4 more rwhp than carby cams but a slight loss 
at 4500 rpm. I think that dip could be tuned out with a good pipe.

--V2 212 cams: Exactly the same as 900SSie cam results

--V2 210 cams: Exactly the same as ST2 cam results