Low Engine Compression - SV650.org

02-06-05, 09:17 AM

Hi all,

I had my 99 SVS (24K miles) serviced recently and they ran a compression test which showed both cylinders down below the service limit.

The bike uses no oil, so I don't think it's the rings or bores, and as both of them are down it seems unlikely that there's a valve seat problem on both pots (or is there?).

Does anyone have any ideas on what this is likely to be.

Cheers,

Gareth

embee · 02-06-05, 10:23 AM

cr@p gauge, wrong technique, throttles not held wide open, battery low and cranking speed too slow, done hot or cold?

.......or knackered engine.

Was it done hot?
What was the cranking speed?
What readings did you get?
(what are the recommended limits?

edit - just checked manual, should be done hot, wide open throttles, both plugs out, battery fully charged, std=15Bar, min=11Bar, cylinders should be within 2Bar. Section 2-30 Periodic Maintenance for curvy types)

Unless it's significantly lower than spec and it performs OK and doesn't use oil and both cylinders are pretty similar, I wouldn't worry.

Why was it done in the first place, did you suspect a problem?

02-06-05, 10:52 AM

Thanks embee.

It was in several months ago as I had problems with it stalling. They said it was the carbs and cleaned them out and it's been running fine ever since. They just did the check, so I don't know if it was a marketing technique

or standard service sir.

I don't know under what conditions it was done or the readings now (must check them up at home) It still seems to be pulling ok and doesn't use excessive fuel or anything like that, so I'm putting it down to your original line and not the second

I'm just giving it the once over - brakes, fuel hoses etc and thought I'd revisit the low compression side of it. May have to borrow a gauge to put rest the paranoia (however slight it is).

Gareth

02-06-05, 09:17 AM	#1
CamScooby2 Guest Posts: n/a	Low Engine Compression Hi all, I had my 99 SVS (24K miles) serviced recently and they ran a compression test which showed both cylinders down below the service limit. The bike uses no oil, so I don't think it's the rings or bores, and as both of them are down it seems unlikely that there's a valve seat problem on both pots (or is there?). Does anyone have any ideas on what this is likely to be. Cheers, Gareth

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02-06-05, 10:23 AM	#2
embee Member Mega Poster Join Date: Jul 2003 Location: Warwickshire Posts: 2,801	cr@p gauge, wrong technique, throttles not held wide open, battery low and cranking speed too slow, done hot or cold? .......or knackered engine. Was it done hot? What was the cranking speed? What readings did you get? (what are the recommended limits? edit - just checked manual, should be done hot, wide open throttles, both plugs out, battery fully charged, std=15Bar, min=11Bar, cylinders should be within 2Bar. Section 2-30 Periodic Maintenance for curvy types) Unless it's significantly lower than spec and it performs OK and doesn't use oil and both cylinders are pretty similar, I wouldn't worry. Why was it done in the first place, did you suspect a problem?

02-06-05, 10:52 AM	#3
CamScooby2 Guest Posts: n/a	Thanks embee. It was in several months ago as I had problems with it stalling. They said it was the carbs and cleaned them out and it's been running fine ever since. They just did the check, so I don't know if it was a marketing technique or standard service sir. I don't know under what conditions it was done or the readings now (must check them up at home) It still seems to be pulling ok and doesn't use excessive fuel or anything like that, so I'm putting it down to your original line and not the second I'm just giving it the once over - brakes, fuel hoses etc and thought I'd revisit the low compression side of it. May have to borrow a gauge to put rest the paranoia (however slight it is). Gareth