Piston Rings

[XJLimited]

I am in the process of resurrecting/reviving a yammy XJ400 which has crank bearing issues.. Now i've always heard the Piston rings are better off if not taken out of the cylinders while dismantling the engine by lifting the cylinder enough so that the Circlips can be removed & with it the piston pins (It used to be a pain but do-able on 2 Cylinder engines but i'm not sure if its possible on a 4 Cylinder engine)

Now my question is, Since the Plugs were light tan & the Compression was good prior removal.. do i need to keep them in the bores for a possible re-use of the rings?

[trbig]

??? I've never heard that before. The only reason I can think of for not pulling them out would be that maybe the rings have kind of gotten into their own little groove so to speak.

Every bike I have ever owned (Except the one I wrecked before I had time to wear it out.. lol) has had the cylinders pulled off the rings. From 2 strokes on up to the 1100's.

I can't even imagine trying to get the circlips and pins out.. let alone trying to get them back in with the pistons still in the cylinders.

Pull the pistons out and the cylinders off... MIC the cylinders. If still in spec, go get a very light honing done. It's cheap and this will help with your compression and ring worries. Just make sure to run the same pistons in the cylinders they came from.


Tod

[XJLimited]

Originally posted by trbig
??? I've never heard that before. The only reason I can think of for not pulling them out would be that maybe the rings have kind of gotten into their own little groove so to speak.

Every bike I have ever owned (Except the one I wrecked before I had time to wear it out.. lol) has had the cylinders pulled off the rings. From 2 strokes on up to the 1100's.

I can't even imagine trying to get the circlips and pins out.. let alone trying to get them back in with the pistons still in the cylinders.

Pull the pistons out and the cylinders off... MIC the cylinders. If still in spec, go get a very light honing done. It's cheap and this will help with your compression and ring worries. Just make sure to run the same pistons in the cylinders they came from.


Tod

Sounded very odd to me too the 1st instant i got to hear about it from a mechanic i knew, he said something about temper/tamper being lost when the rings are taken out of the jugs, Initially made no sense & now it totally doesn't.

On 2 cylinder engines i often find myself installing the pins onto the conn rod hole while the piston+rings are already in the jugs, This usually saves me from breaking one of those rings, Infact i started doing this after i broke one of the Oil rings while i was busy trying to wiggle the pistons into the jugs.

Anyway, Thanks for the heads up tod. Much appreciated

[fredintoon]

Hi XJ,
thing is, when the engine is assembled new the piston rings and cylinder bore are kinda rough and run themselves in to a perfect fit over time. Go pull them apart and then reassemble and that interface gets disturbed and the now really polished surfaces will not re-adjust as easily. That's why it's best to at least re-hone the bore.
Assuming that the piston & bore are still within tolerance.

[XJLimited]

Hey Fred

Makes total sense now

Thanks