Thursday, December 29, 2011

848, 1098 and 1198 air filters wearing on airbox

In addition to the not sealing at the ends issue, I've seen quite a few of these with the air filter worn on the underside by the airbox - the plastic edge is maybe 2mm wide and it cuts into the filter. So now in addition to the rubber at the ends to seal the filter I also add a small piece of stick on foam to the bottom of the air runner flange at the airbox end to lift the filter up a little.

Wednesday, December 28, 2011

A 400 Monster

I rode into the City on Friday with the intention of buying myself a Christmas present - a 400 Monster Ray Quincey Motorcycles had advertised on bikepoint with an "immobilisor issue". I figured that theoretically my software would allow me to just disable the immobilisor section of the ecu and it'd be fixed and ready for me to onsell, making a few bucks along the way. But, as it turned out, the rest of the bike was a bit too rough for me to buy with the intention to fix and resell as I just can't help myself and want to fix everything and profit goes out the window.

I did go for a short ride once we got it going (it was a lottery as to whether or not it would be immobilised every time we turned the key on, probably more so than not overall) and it was just such a sweet thing to ride. The injected M400 have the APTC clutch and 6 speed gearbox like a 2006 620 or S2R800, along with the 2 piston front brake calipers. The light clutch and injection make them so much easier to get off the mark and ride at low speed in general compared to the carby models. It was a real pity it was so nice to ride, I'd have had no trouble walking away from it (as I did in the end) if it wasn't.

One thing I did notice about M400 ads is that everyone seems to list them as M400 S ie regardless of whether they're carbed or injected. Injected ones are from 2006 onwards and have dual front discs. The earlier carbed models have a single front disc and little plastic pods sitting inbetween the frame rails above the horizontal cylinder. More importantly for riding, they have a heavier clutch lever effort (typical non APTC wet) and flat spot from a closed throttle that can be more disconcerting than an actual issue when riding.

I did check and reset the cam timing on one carbed model - advancing the cams from 119 and 113 to 107 degree inlet centrelines which really made a difference. The carbed 400 have the old 750 cams, which were run at 110 degree inlet centreline in the F1, not the 119 they spec in the post '86 motors (the injected M400 have the 800 cams). We also raised the gearing at the same time from 14/46 to 15/46 and the bike still went better than before. But as most M400 are bought by L platers who generally have no interest in spending money other than what they absolutely have to and certainly not anything that (I say) might make it better to ride, I doubt I'll do many others. Pity.

This bike also got the Exactfit ignition coils, so it's a well set up M400 compared to how some of them (barely) run as they've come into the workshop.

I did get one in that was an early 95 model (94 to 97 have silver engine covers with the clutch slave cylinder in the clutch cover on the RH side of the motor) and i suspect it had the very early 600 primary drive ratio. I replaced chain and sprockets as part of a service with 15/46 from the previous 14/46 and even then it was near 8,000 rpm at 100km/h. No wonder the owner had found it breathless above 110 before - it would have been well over 9,000 rpm. I figured 15/41 would be what it needed, but didn't have the time and the owner seemed quite reluctant anyway. The varying spec can make it hard to set them up as they need to be, it seems the importers just put the same thing on all of them regardless.

Friday, December 23, 2011

Happy holiday

Once again we find ourselves at the most frantic time of the year. It's the third time I've made this post, marking the end of my third year in business.

A very big thank you to all those who have supported me over the last three years. Your business is much appreciated. Looking forward to next year it'll be more of the same I expect, although I hope to be both more organised and productive. It's amazing how many hours you can lose some days being busy doing nothing of note. But I guess that's probably a pretty accurate descripton of a one person business.

Happy holiday of choice to you all and I look forward to being as helpful as possible next year. I will be open again from January 9th. You can email me prior to that, but I may not be overly prompt in responding.

Monday, December 19, 2011

Photo from the Festival Of Italian Motorcycles

Rob Labuc took a few photos of my little display at the Festival Of Italian Motorcycles. It was a good day overall. I spent all, but about 10 minutes standing under the (successfully deployed) pergola talking. Rob manned the stand while I had a quick wander around to see what was about.

I did get to have a look at the bike that won my award, Markus's 851SP3. I've known Markus virtually for some time on the 851-888 forum, but had never met him in real life. It's a very nice SP3 too, apart from those god awful bloody blue Samco radiator hoses. Really can't stand them.

My 851 had a nice trailer ride and looked very nice too. I was surprised how good it looked with just a wipe over. For a little while there was a very nice little Bultaco Metralla next to it. A bit of a ring in (woka woka woka) perhaps, but some lovely retro none the less.


Wednesday, December 14, 2011

The joy of motorcycling

Waxing a little lyrical perhaps, but I had to ride home from work tonight due to "my" car being requisitioned by Hunnybunny while her car is being fixed after she got nailed recently. Naturally I had to spend a little time making Minnie go before I was able to proceed, but it was only a flat battery and easily overcome.

A few weeks ago I lavished some attention on Minnie. I realised her belts were (stopping to look at the dyno run dates) about 5 years old, so figured a new pair and some fresh oil and a filter and brake and clutch fluid was in order. And while I was at it I should work out why the throttle was so bloody heavy. I thought it was because the carbs were gummy in the shafts due to her sitting for a couple of years while she was between motors, so took it as a good opportunity to fit the US spec 900 carbs I'd had for some time. My theory was the 900 carbs, being US spec and leaner on the pilot circuits (theoretically anyway), would work better with the 750 than the 600 carbs, which I wanted to make sure I could keep should I sell this motor.

Jets and needles were swapped between carb bodies and the "new" carbs fitted. Turns out the cable heaviness was just cables in need of lube, which surprised me as I thought I'd replaced them for no change at some point in the past. That's the problem with my memory though. But after a thorough lubing (which I generally don't recommend with modern cables due to the linings they use, but who am I to listen to my own advice) the throttle was back to smooth. I'd almost say it's still improving too, given the ride home tonight.

And as I had the oil out it was a good time to pull the clutch cover and replace the collection of second hand plates (I'd added one friction over std, using some thinner steels to stop the hot up induced slipping, but it was god awfully heavy) with a new pack. Yes, new. Oh the horror. Bought cheap on a service parts specials release by NFI, it still pained me no end to be fitting new parts to my own bike. But at least this part was worth doing. Result: lighter clutch, no slippage.

Not such a success was the ignition pick up replacement. Minnie had been idling badly when hot for quite some time, and the few times I had tried to diagnose it resulted in no result. I had convinced myself it was pick up induced, pulling the alternator cover and replacing them with some of the Electrex P8 parts I have in stock. Once reassembled and ridden it was clear I'd failed dismally. So then I moved on to something I should have tried first. Note to self, replace bolt on bits before pulling the engine apart.

As I have the California Cycleworks Exactfit ignition coils on the shelf I fitted a pair of them in place of the green Dyna Minnie has been running for the last 7 or so years. Of course I had to dig out all the original mounting bits removed when the Dyna went on - an appropriately dodgy "just get it going again" job after one of the original coils died. But once I'd found the old stuff the Exactfits went on in no time and the result was indeed a result. Pissing me off no end that I had spent the time replacing the pick ups. But you (well, I) get that. I do have a good pair of second hand original ignition pick ups to sell as some consolation, more so given Ducati no longer supply them as a spare part.

I'd also done the valve clearances and removed the adjustable cam pullies, replacing them with std pullies and offset keys for the desired 107 degree or so (forget now) inlet centreline. All up a lot of work on one's own bike over a day and a half when one has other work to do. And, as it turned out, tonight was the first ride after the coils went on.

I had finished the day with a road test on a typically modded S2R800, and as I arrived back at the workshop I thought to myself "I'd much rather be riding this home than Minnie". But it doesn't belong to me, so after getting Minnie to run and loading her up (I'm not sure of the long term implications of transporting a laptop vertically in a rear sack) I set off. And, I must say, I was impressed.

Apart from, but in no way ruined by the "now lighter, but still a lot heavier than the APTC clutch in the S2R800” clutch the ride was good. Even if only a few km, it was enough to make me smile and I realised when nearly home that I was enjoying riding Minnie like I hadn't for a long time. Previously the heavy throttle really took the edge and some of the middle too off the enjoyment of riding her. But, with the Megacycle mufflers still fitted after the comparison dyno run done a couple of months ago (and shown below in a previous post), she really does run well. And, for a 750 2V motor, go very well too.

Although I'm a bit paranoid to leave the lights in a most sporty fashion for fear of upsetting the laptop. I don't need that sort of aggravation.

Friday, November 11, 2011

1000SS Fork job

Mick, the owner of the 1000SS featured below in the loose screw post, came back to complete the fork rework that was the intention of the previous visit. We fitted some Eibach 0.95 springs (#787-095, 36.4 OD x 297 long) and Motorex 2.5 weight oil, fitting the springs with 20mm of preload (had to cut 17mm off the preload tubes) and setting the oil height to 120mm.

I had the feeling 20mm of preload was too much, which turned out to be correct. With the preload adjusters wound all the way out it only had 30mm of sag with his 95 odd kg on board. So 10mm of preload would have allowed the full use of the adjusters I would assume. Peter from Promecha told me once that 15mm of preload is generally pretty good as a very general rule, and I'd have to say that's advice to be taken.

There were a couple of surprises along the way. The first was the condition of the steering head bearings. With only 7,500km on the speedo some would expect no issues there, but the centering notchiness was enough to make me point and laugh and Mick replace them. Luckily I keep them on the shelf, and the almost greaseless originals were gone in short time.

The second surprise was the forks themselves. First some background - there are two styles of Showa adjustable forks used on Ducatis, or so I thought.

The first style is the 41mm fork initially fitted to the 1991 851. These have a 50mm top OD section (where the top clamp sits) and a 54mm lower OD section (at the lower triple). Fitted to the 851, 888, 900SS and 900M Special, they became 43mm around the same time as the brake calipers went to 65mm mounting pattern, but the outer tube dimensions remained the same. As 43mm they were fitted to the 900SSie, 900Mie, 1000SS, 1000Mie, ST2, ST3, ST4, ST4S, S2R, S4 and S4R. Some had gold TiN sliders for looks, but were otherwise the same internally. Or so I thought. The main internal feature of these forks is that the rebound adjuster, in the top of the fork cap, has the needle valve at the cap. So the oil in the rebound bypass circuit has to flow the full length of the fork cartridge rod to escape. I'm not sure if this is the sole reason for their crappiness, but it does lead to less than desirable action. Not that they are bad forks, and they can be made quite acceptable and certainly better than std with revalving and respringing - as typical of Ducati Showa forks they have too much high speed compression damping among other things. But even with help they have some designed in issues.

Which brings us to the second style, introduced with the 916 in 1994. These 43mm diameter forks are 53mm OD through both top and bottom triple clamps, and their main internal feature is that when you remove the fork cap, it comes out with a long rod attached to it. The rod is about 600mm long from memory - it definitely stands out compared to style 1 above. This rod is again the rebound adjuster valve, but instead of working at the top of the fork, it works at the cartridge, right were the action is happening. The Showa forks fitted to the Aprilia models I have had apart are all this style too (from memory anyway, RS250, RSV Tuono and Falco).

As far as I knew, there are no 50/54mm OD forks with the long rod rebound valve. But when we pulled Mick's forks apart, they had the long rod rebound valve. This bike is a 2006 model, but the same # fork is used in all 1000SS according to Softway, so I'm a bit confused now. I don't recall what any other late model 50/54 Showa have been like when I've had them apart, but I'm sure I've never seen a long rebound valve in any ST4S or S4R forks. The photo below shows the rod I'm talking about, stolen from a post on the Monster Forum from memory as posted by a Swedish fellow who emails me regularly named Torbjorn. He and his mate Thomas with the grenading 888/1026 amongst many others are quite the source of amusement. They have a very cool looking orange 900SSie "rain bike" that is nominally to be used at wet track days. Although it mainly gets used because everything else they or their friends own is failing to proceed. It's by far the most reliable thing they own. The unkind (sarcastic?) would say that's because they tend not to play with it. I think there's a little lesson in there for us all.

Regardless of fork style, as a general rule all the non Superbike forks (Showa and Marzocchi) are sprung way too soft for most people (80 - 95kg) and the Superbike forks are sprung a bit too hard. Most of the SS, M and ST series have a progressive or two stage sort of spring that gives lots of sag with the soft initial section, but then gets very hard and harsh towards the end of the travel. Combined with the high oil levels (usually 90mm or so) and inbuilt excessive high speed compression damping of the Showa they can make for a fairly unpleasant front end.

Anyway, with the 0.95 springs and 2.5 weight oil Mick set off for his hour and a half or so ride home. He had also finally given in to fitting a 14 tooth front sprocket, which takes the gearing from 15/38 to 14/38, much closer to the 15/42 I like so much on these bikes. Mick is a country rider, so low speed city commuting is not something he experiences. But I still like the shorter gearing regardless, and a 14 tooth front sprocket is cheaper than a larger rear and new (longer) chain.

He texted me later that night with the following: "Amazing, a totally different bike, no more harsh crashing over bumps, great control thru bumpy corners, found myself searching for bumps, I never thought it could feel this good."

And finsihed with "14 tooth sprocket is the go for sure." Yes, it is. That's why I suggested it.

Generally suspension mods are something that most owners resist like the plague. But, once they have given in to this non visual expense (I think that's a real issue, you can't see the bits they've paid a lot for) and experienced the difference they act like your typical born again christian or reformed smoker and start preaching the benefits to all (although those who have seen the light of lightweight wheels are generally worse). It really can make that much difference.

As our happy Mick is now no doubt telling all his riding mates.

Festival of Italian Motorcycles November 20th 2011

I'll be at this year's FOIM next Sunday at the new Coburg location. On display I'll have a selection of the parts we're importing from California Cycleworks - the large HM69 Hypermotard fuel tank, timing belts, etc. I'm toying with the idea of taking the 851 out for a ride too. Well, a ride on the trailer to hang out at a new location for a few hours. It's been in it's current location for nearly 3 years, and it's undoubtedly pretty bloody sick and tired of looking at that wall by now, poor baby.

So come along and say hello. I'll be the one standing under the fold out pergola, assuming that 1/ I have managed to get it folded out and 2/ the wind hasn't blown it away. Here's hoping.

Sunday, November 6, 2011

A dyno comparison

I took the chance last week to take Minnie to Dynobike to get a feel for how the new dyno compared to the old dyno. Filled with fresh fuel and running the Megacycle slip ons and ignition map loaded into the TCIP4 to replicate a previous run, the result surprised me and made me a little more pleased with some other things I'd run on this new dyno previously.

Dave thought there would be a 5% or so difference, but the graph below shows the two runs - blue is old Dynojet 200, red is Dynojet 250i. I exported the data into a spreadhseet and it's an average 13.2% difference - varying from 10% under 3,000 rpm to 15% in places. Given the Dynojet is an acceleration dyno the variation may vary with the specific power level of the bike being tested, but I don't have anything else at hand that was run on the old dyno to really know.


Sunday, September 25, 2011

Hypermotard tanks are here!

The first box of Hypermotard fuel tanks from California Cycleworks is here. Price is $1100 delivered to you (additional $25 charge for WA and NT), and, as ever, trade enquiries are welcome. There are two version of air filter kit - 2008 and 2009 being one and 2010 Evo and 796 the other. Please specify when ordering.

Tuesday, August 16, 2011

Cam problem on 1000SS ds

Mick, a previous Moto One employee, bought his 1000SS in today so he could have a bit of a play with it in more equipped surroundings. Plan was to do fork spring and tyres. That plan stalled when he decided to do the belts given they were over two years old and in the process found the vertical cam very hard to turn with the belt off.

So after a bit of a nervous laugh and then the recognition of a potentially much more serious issue he got stuck in, pulling the opening rockers so we could spin the cam fully. This showed that it wasn't a closing rocker dragging, so it was looking much more like cam dragging in head. Nasty. But after we removed the pulley all was revealed and there was a big sigh of relief.

What had happened was that the screws behind the pulley that hold the pulley surround (cast alloy on these engines, rubber on the older 2V motors) to the head had come loose, with one screwing itself out and rubbing on the back of the pulley. Once spotted we could see that this was visually obvious. On the horizontal head the screws were clearly tight, being at the bottom of their recess. You can't get a tool on them without removing the pulley, and the engine wasn't noisy so there wasn't any outward sign of the problem.

So something else to be wary of. You can see the chatter marks on the back of the pulley in the photo below. We're not really sure of the long term potential for damage, but it's not an ideal thing to have happening by any means.

Saturday, August 6, 2011

Staintune clearance sale - 60% off.

Staintune are having another clearance sale. I can't find a web page for the sale this time, so will run the list of usual makes here. There is a full page ad in this months Cycle Torque for all makes. Anything with twins mufflers is $500 ($1300), single muffler $300 ($700). Good savings to be sure.

Aprilia - Falco, Tuono, Pegaso
BMW - R1200S, 1200ST, 1150GS, 1100R, 1100GS
Cagiva - 650 Raptor
Ducati - 1098, M900, M1000, MS4, MS4R

Wednesday, August 3, 2011

Hypermotard Fuel Tanks from California Cycleworks

I have an order in for 5 of the large Hyper tanks - - due in around 4 weeks. At this point of time all tanks ordered will be black. If anyone desires one of the other colours (white, natural, red) please let me know and I can order as required. Retail price will be finalised once they arrive and all freight and customs costs have been paid, but we're hoping for $990 inc gst. A deposit will be required for any non blacks. Trade enquiries welcome too.

Friday, May 27, 2011

New reports up.

More of them! I've been getting some writing done lately, which is nice. A 748 with an 853 big bore kit, a 748SP with reset cam timing and tuning a high comp 900SS with FCR carbs.

Monday, May 23, 2011

Cheap Carrozzeria wheels for Ducatis

If you're in the market for a set of cheap light wheels for single sided swingarm Ducati models, check the specials page on the Carrozzeria web site.

Tuesday, May 3, 2011

New Parts From California Cycleworks In Stock

We now have more of the California Cycleworks parts range in stock, including the Exactfit 2V coils for all carbed and some ie models, fuel sender replacement nuts, case saver inserts and fuel pumps for Aprilia, Ducati, Husqvarna and Moto Guzzi among other things. The Products page - - will be updated soon to show all that's in stock.

Friday, April 15, 2011

New report up - 900SS with FCR.

Shock horror!

I'll add to this at some point as I've just tuned another 900SS with 41mm FCR and JE high comp pistons that was a little interesting and a little along the "assumptions " line from the previous post.

Tuesday, March 29, 2011

Making assumptions

Sometimes when I book a bike in for a certain problem I just head off on the usual path based on the assumption that it'll be like all the others and it turns out to be completely the opposite. I had an ST2 in for running badly around 3,500 rpm. No surprise there, sounds like your normal, not set up well ST2. For good measure I started with the fuel filter, then did the TPS baseline and throttle body set up and figured it'd be good to go. I'd made the expected changes along the way which helped reinforce the assumptions.

Then I went for a ride. And it did indeed run badly 3,500 rpm. Fine at 3,000 and coming good at 4,000, but rubbish in between. Which I found a bit odd. First I tried adding some ignition timing to the eprom mapping because the ST2 can be a little light on advance in that area, but that made little difference.

So I taped the old FIM hand held terminal to the fuel tank and went for a ride. Generally if they're running this badly you need to make fuelling changes of at least 20% to get a change you can feel, and it felt to me like it was rich. So I went leaner and it got better. By moving the zone borders around on the FIM Megazone system you can isolate bits of the fuel mapping as desired to find out where the problem begins and ends. The result was good, but very wacky.

The ST2 has quite close rpm and throttle break points in this area of the map. And the 45mm throttle bodies see quite a bit more throttle opening for a given condition that I'm used to seeing as most of my work like this has been 4V based with the 50mm throttles. Cruising around 80km/h was using about 10 degrees of throttle opening, whereas on a 4V it'd be 6 or so. The rpm break points in the area are set at 3,000, 3,600, 3,800, 4,000 and 4,400 rpm. I didn't touch the 3,000 and 4,400 rpm lines, or any either side of them, and only few points on the 4,000 rpm line. But at 3,600 and 3,800 it was up to 51% leaner up to and including the 25 degrees throttle opening line, generally 30% or so.

On the 3D graph of the fuel map there was a trench in the map at 3,600 and 3,800 up to 32 degrees of throttle opening. Meaning that in this particular area the bike was trapping much less air or had become very efficient. It didn't feel any different, and part throttle performance is hard to quantify in seat of the pants terms.

The only factor I could see for this were the very loud D and D mufflers fitted, but even that's just a stab in the dark. It was nice everywhere else, so it's not like it's an overall issue. Just a very specific rpm related issue at low throttle openings, which given these systems are defined by throttle position and rpm makes it an issue. If they used an air flow sensing system (or carbs, which are air flow sensing devices) this sort of thing probably wouldn't happen.

Made no sense to me at all, and was certainly not what I expected when I made the booking. But you get that, and overall it was quite a bit of fun. Which I can say because I worked it out - it could have gone the other way fairly easily.

Thursday, February 10, 2011

Ducati closing valve clearances and idle quality

A few years ago it took me a while to work out that my bad idling 851 was due to a combination of the soft closing springs the early 851 ran and large closing clearances. I had adjusted the clearances before I got it back on the road after the post sale cosmetic strip and reassemble, but I'd also fitted new steel collets in place of the original stainless ones they ran on 88 and 89 models and the clearances had settled a bit, no doubt helped by the 104 dyno runs it's had. So by the time I parked it last it'd done 6,000km or so since and the idle had deteriorated quite a lot.

The soft closing springs contribute, and I've had to work on a couple of bikes over the years that just wouldn't idle due to the soft closing springs some people fit in belief they'll make more power. Basically it's over 2,000 rpm ok, under 2,000 rpm stall.

The ST3 and 996 issues associated with the closing springs and clearances reiterate how important it can be to general running at lower speeds, and I recall one early 851 owner (possibly of the bike I own) saying it ran so much better after a big service.

Anyway, I got bitten by the excessive closing clearance thing a while ago on a MHR Mille bevel drive. It arrived after having a big service, etc, by someone else and "just needed a tune" to finish it off. So I tried to make it idle. After 15 or so hours of replacing lots of worn out carb bits and checking every thing that I could think of, it still wouldn't idle. I mentioned to the owner that I'd run out of ideas, but maybe it was valve clearance related even though they'd "just been done".

So the owner gave me the go ahead to check the valve clearances. Turned out there was around 0.15 - 0.25mm play in the closers, with the openers largly ok. I took the closers down to as close to 0 as possible, put it back together and hit the button. It idled long enough dead cold to let me know it was better.

More recently I had an ST2 in that had 140,000km on the clock and had just had the heads off. Nominally it'd come in for throttle body set up and eprom to suit the Staintunes, but once I'd done the TPS baseline and fired it up I knew something else was wrong. Namely, it wouldn't idle. Which was one of the things the owner had mentioned. Again, the valve clearances had just been done, but it was the most obvious thing for me to check. And again there was around 0.15 - 0.25mm play in the closers, with the openers largly ok. I took the closers down to as close to 0 as possible (much easier on a belt drive than a bevel), put it back together and hit the button. It idled dead cold like most of the injected bikes will and I finished the tune from there. The hydrocarbon emissions were a little on the high side possibly indicating some valve guide wear (they hadn't been done), but apart from that it was fine. And ran much better.

I have had 1000DS motors in for valve clearances where i've added 0.15mm to the closing shims to close the clearance up too, although most are in the 0.05 - 0.10mm range. I sometimes question whether it's worthwhile adjusting a 0.05mm clearance on a 2V bike, but it appears it is. I do find though that many of the 1000DS cams have a tight spot at the end of the closing lobes just as the valve starts to open. You can feel movement in the valve when rotating the cam around the base circle, but it will rub as you get to the lift points at either side. So there's always going to be 0.02 - 0.03mm clearance at TDC firing to allow for that.

On the 4V bikes I always take the exhaust closing clearances down to 0.05 - 0.07mm and the inlets to 0.08 - 0.10mm, going to the tight side if the collets are broken and have to be replaced. I've not owned a later 4V bike to know if it really makes a difference you can feel, but it doesn't hurt.

Saturday, January 1, 2011

Airbox mods when fitting FCR to Ducati SS and Monster

Last time I fitted some FCR to a 900SS I took some photos of the airbox trimming for future reference and thought I might as well post them here too. To do the trimming I use an electric die grinder with a very coarse conical bit. It looks rather medieval, but when it's honking around at 26,000 rpm it's amazingly easy to use gently.

I find you can refit the breather hose to the airbox too, even though the Sudco instructions say you can't. It can be routed under the throttle cables. You need to round the edge of the box below and behind the breather hole to get it all to fit nicely, but if you go gently you can make enough room.

Cleaning under the fuel pump, etc

One thing I do when replacing fuel filters on the bikes with removable plates in the bottoms of the fuel tanks (916 series, MV, ST series) is remove the fuel pump from the mount plate and clean under it. On these models the pump's rubber sleeve pushes into the mount tube and is held by a raised ring on the sleeve - you can see the corresponding groove in the photo below. You just pull the pump out (possibly easier said than done), maybe lubing the rubber to make it slide nicely. What you often find under the pump at the bottom of the cavity is shown below - lots of debris and rust. I've seen the cavity full to the bottom of the pump screen with gunk.

749 and 999 have a plastic cover held on the the press nut type of steel clip that you can't reliably reuse, and I haven't spent the time to find the replacements for them yet. Probably the same size as those used to hold the fairing insulations on.

It's always a good idea to have a new O-ring on hand when doing this job, as the one that's been in the tank for some time will usually swell as you remove it. Use lots of grease on the O-ring and tank rolled edge when reassembling, as it's fairly easy to take a piece out of the O-ring which will cause fuel to leak at a significant rate. 916 series, ST series and MV models use the Ducati part 88650011A. 749 and 999 use a smaller ring - 88640331A maybe (from memory).

The Aprilias usually have a black plastic screw on cover over the pump pick up screen, so similarly I always remove and clean the pick up cavity when replacing a fuel filter on them. Like the Ducati models with plastic fuel tanks, there isn't a specified fuel filter replacement interval on the Aprilias. I tend to do them on the 20,000/22,500km service depending on the specified intervals for the particular model. In my experience it's worth doing, as even though you don't get any rust inside the plastic tanks you can still get the gummy build ups.

And on all models always check the breather and cap recess drain tubes or hoses through the tank and hoses external to the tank are clear. If you can't blow throught them, they need to be cleaned. Old cable inners are great for this, as they're flexible, but stiff and strong. Just be careful if you're going through plastic or rubber though.