CCS / ASRA Racing Forum

All the other stuff => Wrenching => Topic started by: sv303 on September 24, 2006, 10:24:32 pm

Title: SV650 compression?
Post by: sv303 on September 24, 2006, 10:24:32 pm
Has anyone taken a compression reading of a stock sv650? (1999-2002) In the manual it states that the standard compression reading should be around 213 psi, the lower limit is 156 psi, and the difference between the two cyclinders can be 28psi.  My rear cyclinder is 195psi and my front is 230psi.  I'm not sure if this is a problem or not.   I'm just trying to find out what others have?

Thanks

Kevin
#303
Title: Re: SV650 compression?
Post by: SV88 on September 25, 2006, 12:02:55 am
I'd say it's a bit of a problem... Mine (00 with 34k miles) are both around 200 psi.  Where do you get the specifications?  I think our motors are roughly 10.5:1 which translates to 175 psi (14.7 psi per atmosphere).  YOu probably have some carbon build-up in the rear cylinder which tends to run a little richer ... I suspect that's your high compression cyclinder.

Steve.
Title: Re: SV650 compression?
Post by: AZ-MilleR on September 25, 2006, 01:36:07 am
I remember being aorund 195 / cylinder when I tested my 2001 SV last year, and both cylinders were very close.
Title: Re: SV650 compression?
Post by: grasshopper on September 25, 2006, 04:50:44 pm
Time for a leak down test.
Title: Re: SV650 compression?
Post by: sv303 on September 25, 2006, 08:56:21 pm
I just did a leak down test,  both cylinders are right around 10 %.  The front cylinder is the one with high compression. 
Title: Re: SV650 compression?
Post by: Super Dave on September 26, 2006, 08:00:19 am
Been a while since I've been around lead down numbers, but 10% seems to be a lot.
Title: Re: SV650 compression?
Post by: Protein Filled on September 26, 2006, 08:22:29 am
230 is really high for a stock motor. Is there any work that has been done to the bike? If you really have 230 Lbs of Cold Cranking Compression you need to run high octane fuel since you may get some detonation. If the motor is 100% stock, I would double check carbon buildup as well as cam timing. Sounds to me like it's time to freshen her up. I had one SV that was up to 250 lbs and we toned it down since it would be too easy to grenade something at that rate.