Bikesure_adrianflux

Valve Shims

  • Thread starter Thread starter analogue_rogue
  • Start date Start date
im gonna remove head ans im gonna spray the engine up and put black barrels with aluminium grey heads and crank.... i have the paddock stand.. so it may be eassier once i have sprayed the engine and reassembled.. but i think its probably easier with the head off....
 
I measured clearances and took my old shims + values for the clearances to my local Ducati dealer (JHP in Cov) and the parts guy measured up my old shims and gave me appropriate sized replacements. Luckily they was a tiny bit oversized, so I carefully ground em down a bit to correct measurements on a bit of 240 carberundum paper.
 
If the heads are coming off anyway, then doing the valve clearances will be a relative breeze.
 
update... heads are off.. i have a micrometer this weekend.. but i cant get this damn measuring tool! and im a little too tight to pay £24 for something ill use a couple of times..... any trusting people out there have one i can borrow?
 
Very interesting vids, wondered how the valve gear worked. Why did he push down the closing rocker to measure the closing clearance though? What force is he trying to overcome?
 
Theres a closing spring that is looped around the pivot shaft, pushing down on the rocker arm removes any pressure the spring is applying.
 
But where are you guys getting your shims from what with all this bloody COVID-19 and the likes and bike shops being shut?

I have a natty little Excel file that helps with the calculation if anyone is interested, it's not my work and originally it was used for an ST3. is there a way of uploading a file to the forum?
 
1mm closing clearance

I have got my vertical head off at the mo so checking the clearances, all but one are close but one exhaust closer is 40 thou, serious amount of movement, I now need to pull the rockers and cams but I can't see anything wrong so far it must have been badly calculated and not checked or is there another possible reason for this.. Thanks. .
 
collets not properly seated or replaced upside down?
is the valve stem stable in the guide?
is the valve sitting right in the seat (stem straight and seat cut/lapped properly)?
 
The love seat is good, I thinking the collet may be the issue, iv got the open rockers and cams out just on the closers now, trickier with the springs...
 
I generally use a small aluminium drift and a toffee hammer and tap the valve stem to ensure everything’s fully seated after refitting the collets. Look for the polished edges to ensure the collets are the same way up as the where before removal. I also always turn the engine 720deg by hand and recheck everything when i’m done.
 
Thanks, I'll follow that and make sure there well seated, that's if I ever get it back together, I have some pitted rockers to deal with now, vertical cylinder, intake right hand opener, exhaust left hand both, I am going to post an ad on here as I really can't do new prices at this time, have already spent quite heavy. Any help on cross compatability with models would be appreciated, I believe st4, s4r are the same but there are likely others??


 
Terryphukwit said:
Any help on cross compatability with models would be appreciated, I believe st4, s4r are the same but there are likely others??
Click to expand...

Basically all 'Desmoquattro' use the same rockers; 748, 851, 888, 916, 996, ST4, S4, S4R but not the 'Testastretta' 998cc versions onwards such as S4RS, 998, 999, 749 etc.

As it happens, I have some spare rockers if you're interested.
 
Dukedesmo said:
Basically all 'Desmoquattro' use the same rockers; 748, 851, 888, 916, 996, ST4, S4, S4R but not the 'Testastretta' 998cc versions onwards such as S4RS, 998, 999, 749 etc.

As it happens, I have some spare rockers if you're interested.
Click to expand...

Thanks, and that would be awesome, I need 2 x left hand openers and 1 x left hand closer..would you like to pm m with the price..
 
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