It's time to check the valves on my 998. Last time I did it I though about 6 shims needed to be adjusted, but when I dropped it off at the dealer they said only one was out of clearance.
This time I want to make sure I understand how to measure the clearance, so I've attached two pictures here.
My questions are:
Am I measuring at the right place for the closing rocker and the opening rocker?
The first picture would be closing rocker, the picture with my hand in, is the opening rocker?
I've rotated the vertical cylinder shown in these pictures to TDC compression stroke. As far as I understand, both valves are closed in these pictures?
The mark on the timing wheel is lined up with the mark in the inspection window.
The testastretta does not use the loaded/unlodade method the measure the clearance?
The Desmotimes book says 0.18 mm for opener, 0.13 mm for closer. Is this still correct?
The Desmotimes book also says to rotate the cams so that pressure is taken off the closer rocker and then take the measures, and then refers to the previous chapter, that is describing the desmoquattro!? I'm very confused here.
Is pressure taken off the closing rocker when piston is TDC compression?
Any help greatly appreciated!
cheers
ps. I searched and search for any good tutorials on testastretta with pictures but couldn't find any. Sorry if this is too basic questions.
I haven't looked at the video (link you posted) because I'm on dial-up.
Yes, you're checking the clearances in the right place.
My S4RS manual says nominal opener clearance is .20mm, ,operation .18-.23, checking clearance .10-.25 (whatever checking clearance is?)
closers, .15mm nominal, .13-.18 operation, and .10-.25 checking clearance. (my guess is checking clearance is the max they can be out before they need changing but don't know for sure).
My area DNA Tech. rep. said to set both openers and closers at .06-.15, .10mm being optimum and gain a couple of HP. this is for S cams, don't know about the standard cams. (would think they would be the same)
I got hold of the workshop manual as well, so I should be able to take the correct measures now.
The last day at the track I noticed the engine didn't sound as usual when revs were close to 9000 rpm, or maybe it was only my imagination, or a loose ear plug.
Hopefully its only the heads that needs service.
Possibly, but probably only if the clearances are really bad.
Don't overthink this.
.06 mm for an opener is way tight. Don't do that, I don't care who said it. Follow the specs in the manual.
You probably only needed 1 shim adjusted the second time because valves tend to settle in after some period of time. When the bike is brand new, the valves move a bit. Then that sort of stops, and usually your valves won't be adjusted for quite a while after that unless you are absolutely beating the ever loving shit out of it, or you have really wild cams (stock engines as race bikes usually stay pretty good for a while as long as you're not always on the limiter). Then once the guides start going the seats and valves get f'd up, the clearances start changing again, a good indication you need a rebuild.
I prefer to measure in inches since the increments are often smaller than metric.
If you run the engine hard, it's not a bad idea to change the retainers (collets, half rings, whatever they are called these days). You usually tighten up the closer clearance .001 to .002" (.025 to .5 mm) with new retainers, if the old ones are pretty worn. So if the closers are .002" loose, throw in retainers. I think they are still cheaper than shims?
Do yourself a favor and take the oil cooler off it's mount and pull it around under the bike somewhere (no need to take off the lines). You will soak it with oil, and it "never" comes out. I learned the hard way.
__________________
'01 996 (ASMA #17, rebuild complete, runs, needs more stuff as it goes with Ducatis)
'01 MV F4S
'02 998 www.asmaracing.com www.desmosouthwest.com
Sure wish I understood German! I like when you can watch it a few times to get a better understanding before jumping in head over heels not knowing what the "f" your doing!
Since my last post I've pulled the cams, looked at all the collets and rockers. I could see the collets being slightly worn but the rockers and cams are mint.
This was the first time I've pulled the cams. I marked the cams and the belts so that I could put them back on properly. It was really straight forward.
Today I dropped off the bike at the dealer and we agreed on changing the collets and re-measure it from there.
(I also saw two 1098r at the dealer being serviced, stunning bikes!)
Last time we did the shims was September last year. So this will be a good indication how things are wearing.
I try to be nice to the bike when I'm riding it. I change gear around ~9500rpm and never hit the limiter.
It will be interesting to start it up again (probably next weekend)
Quote:
Originally Posted by acruhl
Do yourself a favor and take the oil cooler off it's mount and pull it around under the bike somewhere (no need to take off the lines). You will soak it with oil, and it "never" comes out. I learned the hard way.
Ahh, now you tell me! Yes, the cooler is nice and greasy now.
I'm thinking about taking my oil cooler off the next time I do oil and soaking it in solvent. It's making the fairing lower dirty, b**tids. I was warned and I just put a rag in there and it wasn't enough...
So why did you end up deciding on changing the retainers? I decided not to do it on mine just because I know those things wear down a bit and then settle in. I've done a few track days since I got it and I'll probably do them next time. I'm not sure exactly when the right time to change them is, I'll have to check the manual. The shiny side (on the inner part) goes up if I remember correct. If you flip them over you end up getting the closing clearance different as if you put in new ones.
I did the same thing with the belts. Just make some marks on the cam wheels and you're good to go. I changed my belts, unfortunately they cost $200 here. That's way more than 996 belts. Oh well.
On my last track day I was changing gear around 9000 and not necessarily holding gears that long except on the straights. What a wonderful bike this is... Once you get the geometry and clickers right, it's just wonderful. I need to get a stiffer spring on the rear and the fork oil changed to really finish it off.
__________________
'01 996 (ASMA #17, rebuild complete, runs, needs more stuff as it goes with Ducatis)
'01 MV F4S
'02 998 www.asmaracing.com www.desmosouthwest.com
Since the closer clearance was too big, and the retainer showing some wear (a tiny flat spot), I thought it would make sense, and be a cheap? insurance, to put a new retainer in there since you have to take them out anyway to change the closer shim.
Maybe I'm just paranoid and have been reading too many internet stories, but I prefer to be on the safe side.
But I hear what you're saying, the new ones will wear down a bit and then settle in, so next time I check clearance, things have moved again?
I just read the workshop manual. The only time the mention to change retainers/collets is when you disassemble the head, but I might have missed a chapter.
It's a sweet handling bike for sure!
I put a stiffer rear spring on, only .5 heavier, but it made a huge difference holding the line in long sweeping corners.
I've read, each 10mm change in wheel base as you change the eccentric wheel hub, equals .5 in spring rate?
I also have RaceTech internals in the Showa forks, 27mm offset tripple (24.3 rake) and mag wheels. I have no problem keeping up with the modern thous on the twisty tracks. Great stuff!
Last edited by 998Cruiser; 08-07-2009 at 05:04 AM.
I agree that .06mm is too tight! I set mine (testastretta's) at .10- .13mm.
I use the MBP collets in my bikes but on other bikes that still have the stock half rings I change the shim if they need to be changed (grind on a surface grinder to get perfect) and put the old half rings back in the same position. My theory is that when new they will "hammer" in a bit which work hardens them,then they are already "hammered" and worn in so they don't move from there as quickly. I also de-burr the little suckers when installing new ones.
just my, everyone should set them however they want to
On a testastretta you can reduce clearances so things don't hammer around in there so much. Closers can go down to .002" with openers .003". The top end is a bit quieter also with these tightened values.
I replaced the half rings in mine at 20,000 miles. Note that the half rings are poorly made things with horrible burs on the ends where they were cut. Check them and file down these burs so they lay flat and give you an accurate clearance reading. They also vary in thickness more than I'd like to see so I did my best to match them on a particular valve. Pretty shoddy work considering the price for these things.
Its Personal preference and beleif, yes.
I run the closers real tight to save the seats, as close to nothing without binding, openers around .15mm and not under .12mm.
Same as obove closers tight as they go without binding or 0.05mm tops . The gap will get slightly larger (0.02) after the seats/collets have bedded in. I do all openers at close to or just over 0.12mm/0.13 mm using a go-no-go guage . After settling in they end up or not far over 0.10mm.
The bikes do seem to run better plus they idle with light or no springs when tight
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You didn't tell us what closing clearances you are using Tom? What is really tight?
Seems like you should have something in there. .002 seems fine, but I'd like to be able to check for binding like you say. .003 for an opener seems awful tight, especially on an exhaust. I guess the old air cooled motors had a spec of .000 as long as you could spin the shim with your finger or something. It's a different setup though.
Someone said something about light springs, is there someplace you can get those for testastretta motors?
__________________
'01 996 (ASMA #17, rebuild complete, runs, needs more stuff as it goes with Ducatis)
'01 MV F4S
'02 998 www.asmaracing.com www.desmosouthwest.com
I Start with the closing shim binding a bit and then sand until it doesnt, so 1 to 3 hundreds of a mm or so, depending on how many times your patience allows to remount and check I wouldnt fall into tears over 5 hundreds either.
Especially with fresh seats I want to keep them zero as the will move up a bit.
I Start with the closing shim binding a bit and then sand until it doesnt, so 1 to 3 hundreds of a mm or so, depending on how many times your patience allows to remount and check I wouldnt fall into tears over 5 hundreds either.
Especially with fresh seats I want to keep them zero as the will move up a bit.
+ 1
__________________
life is work
For Ducati engine blueprinting/crank balancing/performance cylinderhead prep/ porting / big valve conversions-www.cjsracing.co.uk
For 1st class dyno-tuning ,mapping, custom eproms- and a whole load of other cool stuff www.hypertrick.net
Yeah, that's a good point. With new seats and new collets it's going to hammer itself inward probably at least .002". Which means that .06 mm (about .003" I guess) opener clearance someone mentioned earlier could get uncomfortably tight.
__________________
'01 996 (ASMA #17, rebuild complete, runs, needs more stuff as it goes with Ducatis)
'01 MV F4S
'02 998 www.asmaracing.com www.desmosouthwest.com
I Start with the closing shim binding a bit and then sand until it doesnt, so 1 to 3 hundreds of a mm or so, depending on how many times your patience allows to remount and check I wouldnt fall into tears over 5 hundreds either. Especially with fresh seats I want to keep them zero as the will move up a bit.
Bingo!
And I profess tight tolerances... So when do I learn about tight clearances? Of course the day after I screw my engine back together after a valve adjustment with things set at the .003-.004 inch values.
Looking at it the 2V engines, they use tight clearances so why not the strettas.
It all boils down to the manufacturing level. Taking the time to set things tight at the factory takes time and time is money. Pure and simple.
So tighten 'em up guys, there will be less commotion in the valve train and you will likely decrease your needs to re shim by 3 times. Perhaps never need to re shim once an engine is bedded in at say 10,000 miles.
measuring valve clearance
Yes, the cooler is nice and greasy now.
, everyone should set them however they want to
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