New pistons and rings @ 28k miles???(UPDATE)

They attach a new downpipe onto the cylinder, then put pressurised air into the bore. They check where the air comes out (if at all) to see what the problem is.

[embee]

Was there actually any problem that you'd noticed with it before it went in for service, or is this something they came up with out of the blue?

A compression check isn't a normal part of a routine service, be it 3k or 30k miles. It's something only normally done if you're trying to diagnose the cause of a specific problem.

All sounds a bit iffy anyway.

Originally Posted by embee

Was there actually any problem that you'd noticed with it before it went in for service, or is this something they came up with out of the blue?

A compression check isn't a normal part of a routine service, be it 3k or 30k miles. It's something only normally done if you're trying to diagnose the cause of a specific problem.

All sounds a bit iffy anyway.

No just put her in for her 30k service and sort the noisy camchain out, so yes hes announced this out of the blue, he was also trying to tell me taht the filters/plugs and oil needed changing...ermmm no shes only done 700miles when id done all that!

I have stripped two SV engines, one at 8,000 miles and one at 12,000 miles. I would say that it is far more likely that exhaust valves would be a compression problem way way way before piston rings...

sounds fishey to me too

I am just now using enuf oil to be of concern with 133k, at my next service (135k) I will have my dealer do a compression & leakdown test, and my guess is that they will find that my valve seals are shot and valve guides worn beyond tolerance

even with as much oil consumption as I have, the engine still runs great, actually as good as it has ever ran, I have not noticed any loss in performance or fuel economy

Its not out of the question that it has low compression, but I’d be surprised if the rings are worn out with that sort of mileage. You say it doesn’t smoke, smoke would be a good indicator of worn/damaged rings, but not definitive.

As others have said, if it is low compression more likely to be a valve clearance/seat issue than rings.

A ‘leak down’ test is indeed better than a simple compression test, but only in identifying where low compression is coming from. i.e. a compression test (can get/borrow one of these cheap/easy) is all you need to do to know you have a problem, the ‘leak down’ just tells you where.

Another indicator of low compression is poor idling. What does the bike idle at?? You say it runs fine (when going presumably) and if it will idle at say <1k* then I really don’t see you have enough evidence to explore further.

*Low compression will have more pronounced effects when the engine is running slowly

If it is rings causing the low compression things will get a lot worse/noticeable before you need to address it. Presuming it is ring wear and not a breakage, then the engine won’t come to any harm if you just run it and see if it gets any worse.

So in summery, unless you have ‘running problems’ then just keep running it!!! Or at least that is what I would do!! … but that me

Cheers for all the advice guys.
Got her booked in with another mecahnic for sat afternoon, one i know and trust!, also my local bike dealer who i get on well with has said taht i can run it over to him nad he'll get his service guy to check her out.

Originally Posted by Paws

Hey guys,
serious advice needed, my sv's in for her 30k service, and the mechanic has rang me and said she needs new pistons and rings??!!!!!! as he did a compression test and shes 60-65% DOWN .(or so he says)
(

If the bike were in need of new pistons as well as rings ( which I fail to see how he can diagnose this without taking the engine apart and actually looking at both to be sure) and compression was down by as much as he states, you would have felt the lack of power.

It would feel sluggish and struggle to hit top end speed. Failed piston rings do not always mean that it burns oil out the exhaust.

If you are not sure, take the bike back and take it for a good ride. See if you can feel the difference.

Troublesome thing is, he will have stripped down the bike in order to complete the compression test. If you decide not to have the work done, then find that it does need doing after all, he will charge you again for the same work he has already done.

[jambo]

Originally Posted by BigApe

Troublesome thing is, he will have stripped down the bike in order to complete the compression test. If you decide not to have the work done, then find that it does need doing after all, he will charge you again for the same work he has already done.

Assuming he's just using a normal compression tester of the type I've seen on sale at Halfwits all you need to do is pop a spark plug out, press the compression tester in the hole left by said plug and turn the motor over. Doesn't seem like a lot of work

Then, what do I know never done a compression test in my life

Up dated, see my first post-its NOT good news.