Does anyone know the compression check numbers for a stock bore/piston DS without disengaging the decomp lever?

I'd do it the "right" way but I'm soooo tired of wrenching on it lately. The compression gauge says to check compression when the motor is warm. I'll try that Monday, I did it cold tonight & got 145psi. I've read 180-220, I'm hoping that is measured by disengaging the decomp lever. Otherwise I'm SOL.

Thanks

 

On one of my old motors (COLD) I got 180psi without cracking the valve cover I think it was 11:1 or less. Decompression lever NOT touched. At least this is your only prob IF it is the prob. If you dropp a lightweght high comp pistonn in her and port the head while she is out your ds will be an animal. Your pressure sounds low... Im gonna go and do a search, just to see.

I think you might be feeling the loss of power from lack of cyl pressure. JMO

 

I looked around and some credible people have said even 120psi is normal... I guess you will get a better reading from decompression lever open.


Now that I think about it, If your temp has rised and you feel lack of power on top end it could simply be your main jet. I would take it down 2 sizes or do a plug check after WOT. You might just be too rich due to higher temps. Ive done this with running higher octane and too rich.. I felt major power loss. You might want to check your plugs. The outside temp changes alot. Good luck. Maybe someone more motor savy can reply.


If your bike runs great in the winter and weak in the summer you are too rich with higher temps.

 

I've tried about every possible jet/needle setup this spring. I used to run Mikuni 170 with needle on 5th notch or a DJ 185 with DJ needle on 4th notch. I've been lower on both needle & jet & higher on both with no success. My pipe has a cracked weld (about 40%) around. I'm hoping that & old packing is all my trouble. Quite honestly I'msick of messing with this quad & mad enough to sell it.

 

Still not doin what ya want. If ya need a hand let me know, I will help.

 

01ds650 and I both did compression tests and both our quads were about identical with mine being 150psi. This should be a good number for a bone stock ds650 since both run really well. His quad is runnin better now since we put a diff mainjet in it and adjusted the idle circuit. You know it's funny too because he did the stock carb modds and I hav'nt and we could'nt tell a diff between his carb performance and mine. Incase your wondering, no I don't actually have the tm45 on the quad yet lol. I think I am gonna save it for the predator since I wanna put the cbr600f2 in the ds.