Replacing rings

[BDT]

I'm curious if this is something I can survive taking on by my self. I'm pretty good at wrenching, love to do it, and have been doing it for quite a few years on cars, but I've never cracked open the bike. I've done the breaks/lines, gears, clutch cable, and have taken both wheels off a couple times, but I've never gone inside the engine and am worried about getting in over my head.

I know bikes often require specialized tools that I'm not going to have. Is replacing the rings one of those jobs I'm going to regret? I'd sure like to save a few bucks and learn a little more about the bike.

What do ya'll think?

BTW, the patient is a '93 CBR 900rr that's started smokin' pretty bad at high revs.

[wulf]

shouldn't be too hard, if you don't have the manual, get it.

read up before hand, ask around on the 900rr websites, etc

biggest thing you need is a tourque wrench in inch pounds, everything else you can do with normal tools or fake it.

if you want i'm down to help.

it's alot easyer if you pull the motor, saves the back a bit, though i've done major work with it in the bike too.

and don't count on having it done in a day, take your time, do it right, and inspect everything.

[Bryce]

I would definatly have the head done by a machine shop as many times smoking is caused by oil leaking past the valve guides

[Buddau]

You will need a cylinder hone to restore the cross hatch.

[Bryce]

You will need a cylinder hone to restore the cross hatch.

on that note it's probably easyest too just drop the head and cylinder off at a machine shop to have the cylinder honed and have the valves redone and maybe even mill the head while your at it

[Buddau]

See how these kind of jobs snow ball into a complete rebuild?
My point isthat if you replace the piston rings, you must restore the cross hatch. Otherwise the new rings will not seal.

[Bryce]

I look at as a case of why do it halfway? seems silly to tear a motor down and not do at least a complete freshening

[Anonymous]

You will need a cylinder hone to restore the cross hatch.

Speaking of which... There was a post in here somewhere (or maybe a whole thread) about cylinder machining, honing, etc specifically talking about how the best way to do this is on modern engines WRT the tolerances required. I think that guy who works for an oil products co posted it (Tom-something? maybe)... Would be worth searching through and reading that before you go grind metal.

[towneh]

i think it is "Gramps" who works for WIX filtration....

here is a segment of the post...

quote//Also to understand why this is not necessarily bad for an engine of any type any more. You must first understand the technology that goes into a modern day engine. They dont mill the aluminum with rotogrinders and sanding tables any longer. That is old technology. Now everything has a RA(roughness average) number on all the sealing surfaces. This would include the cylinder walls after about 2000 or 2001. For example your average cast iron block and heads have an RA number over 100. Todays
aluminum has RA factors between 3 and 15 according to what the manufacturer wants it to be. This finish is the equivalent to a piece of new glass. The gaskets they are using are made to work with these type finishes. Piston rings became the same way in about 2000. There are only a few manufacturers in the world, and they all changed at the same time for warranty purposes.

So yada yada yada... what this all means is, today's engines either seal or they don't. There is no in between. The tolerances and ratios are there. So is it better on a DYNO? YES. But only because it is a controlled environment and it takes less time.

This also means on a newer bike you have to be more careful about who does your machine work. If you see someone cross-hatching a cylinder wall with stones or such you might want to find a new machinist. A good test is to ask the shop if they can measure RA? If they look at you like you're stupid , or don't even have an answer call me. I have a $3000 tool //quote

-memory fading-
henry

[hcr25]

My motor is at H O Motorsports right now.I agree why do it half way.Ron does awesome work in a timely fassion I highly recomend him.If you need or want more info about him just let me know.Mike

[jah]

do some compression testing to determine if rings or valve leakage, get numbers up front.