All, I am attempting for the first time to adjust the valves on my 2002 998. All the opening and closing shims for the exhaust side on both the vertical and horizontal cylinders are in spec. The closing shims on the intake side are also in spec. However, the opening shims on both the vertical and horizontal cylinders on the intake side are entirely too tight. In fact, I can't fit the smallest feeler gauge in to find out the measurement. I know this isn't normal, so perhaps I am doing something wrong? Any help would be most appreciated.
Can you hear/feel the cams binding on the shims as you try to rotate? Sorry for the silly question, but do you have the engine at TDC on the correct stroke when trying to take the measurements?
The engine is at TDC. I checked it several times. The belts are off as well and I measured with cam lobes pointing upward. After a night's sleep, I checked the valves on the vertical cylinder and with some force I did manage to get a .005 feeler gauge under the openers on the intake side. Unfortunately, I do not have a smaller measurement but I assume it .004. Perhaps I shouldn't have tried to measure the valves at night after a long day at work. Is it normal for the intake shims to be tighter? I should have probably mentioned that my bike has over 40,000 miles on it and I have no idea when the valves were adjusted last.
So by 0.005, you mean 0.005" or 5 thou? That's 0.127mm which may be too large to measure the clearances. On the desmoquattros, some common clearances are 0.1mm on inlet openers (4 thou) or 0.15mm on exhaust openers. You might need some smaller metric feeler gauges for these clearances. I don't have the service manual for the 998, so can't comment on what the clearances on these engines should be.
Yeah, I mean 5 thou. I think the measurement is probably 4 thou for the inlet openers. But I will find a smaller gauge to confirm. Thanks.
you need a thinner set of feeler gauges the service manual for the 998 says this sorry corrected Opening rocker arm Intake Nominal 0.20 mm In operation 0.18-0.23 mm Inspection 0.10-0.25 mm Exhaust: Nominal 0.20 mm In operation 0.18-0.23 mm Inspection 0.10-0.25 mm Closing rocker arm Intake: Nominal 0.15 mm In operation 0.13-0.18 mm Inspection 0.10-0.25 mm Exhaust: Nominal 0.15 mm In operation 0.13-0.18 mm Inspection 0.10-0.25 mm but many run tighter clearances, brad "thebikeboy" black recommends "i use io 0.10mm, eo 0.15mm, ic 0.07 - 0.10, ec 0.05 - 0.07" all dims in mm
One last question: I have an oil leak from the horizontal rocker cover. What is the appropriate way to seal? I recently installed a new gasket with some sealant and it leaked worse than before. It also leaked from one of the bolt holes.
there should be rubber covered washers under cover nuts, if these aren't sealing make sure they are the right way up (rubber side down) . if they are installed right and leak, you can use a bit of sealant under there to get you out of trouble, but ideally get new ones. also check the inner lip of the cover for dings marks or debris where the gasket might leak i put a thin bead of sealant pretty much all around the underside of the gasket (be careful not to block the oil holes in the cam caps) you also need to put a bit of sealant around the lip of the spark plug hole
Interesting. The rubber under the bolts doesn't seem to be sealing. I think I need to get some new ones as you suggest. Thanks.
