TOPIC:

Hey guys, i rebuilt my engine this last winter because it was loosing oil due to dried out valve seals. I broke my motor in fine but then started to notice i was loosing about a quarter of a quart of oil in about 50 miles. Its not smoking terribly, but I do see some from only the right side exhaust when i rev high at idle it'll smoke as the revs fall back down to idle. I don't notice any smoke when riding but im not in the habit much of staring behind me. Pulling plugs, i found cylinder #4 to be darker than the rest and every other cylinder looked okay. Darker but no where close to fouled. Anyways, im assuming my oil rings in cylinder #4 were installed incorrectly or just didnt seat for whatever reason so i need to pull the top end again.
My question is, would it be okay to leave cylinders 1,2 &3 alone and reuse the rings that have been fine in those cylinders and just replace the rings on #4. And do i need to hone the cylinder again? I stuck my inspection camera into each plug hole and can see a clear cross hatch in each cylinder and saw slight carbon on top of each piston except #4 looked clean and shiny like it has a light coat of oil. Would it be glazed after just a few hundred miles enough to need to be honed again before putting back together. And does every gasket need to be replaced or can i get away with reusing things like the rubber cam chain gasket and the little o rings. I plan to have to replace the base and head gasket but figured the rest should be okay.

Thoughts anyone?, thanks in advance

Your plan seems reasonable to me. Be sure to inspect all the rings carefully and you might want to perform a leak down test (hot engine) before busting down the engine again to be sure you have a good ring/valve seal.

These motors are agricultural by todays standards but not as leaky as old Brit bikes. I don't think mixing new and old rings will matter much. Might matter if the motor was highly tuned and raced but for street use, nah don't worry about it.

You won't know until you get in there. Could be just a mis installed oil ring. Going through all that trouble and using old gaskets is a prescription for disaster. I would gather what you will need before opening it up.
Steve

cafebrat wrote: ........when i rev high at idle it'll smoke as the revs fall back down to idle.....

Why do you do that? Ed

See.....

Hey Ed,

I think he's just trying to find out what is wrong with his engine - I'm assuming he knows better than to rev an unloaded engine with chain driven overhead cams up to redline for no good reason on a regular basis!

Re -used gaskets and O-rings????? Why???? Not that expensive, and you'll be extra-specially regretting not spending the money if you have to tear it apart again....My #1 choice in inexpensive aftermarket gaskets is the Vesrah set #439.

Rings? in your case I will say inspect them all, and if you can't detect any defects, you should be o.k. with re-using them. If the cylinders only have a few hundred miles on them, just a few passes with a flex hone and put the parts back together in the original locations and all will be good. If you find only one set of rings defective (your no. 4 is the suspect - right?) then be sure to get the same brand of rings to replace them - don't mix and (not) match!

No. 4 piston is clean on top but wet...find out what is whetting no. 4 before taking it apart! Is it fuel or oil???? Ya need to know!

Thanks for the replies guys.
Yeah im not red lining the bike revving it constantly, i just couldn't figure out where i was losing oil until i noticed my axle nut was all black and sooty so i gave the throttle a few quick 3/4 throttle revs and could finally see some smoke as the bike returns to idle.

Ill spend the $$ and just replace all the necessary gaskets for piece of mind.

Ill see if i can get cylinder #4 at TDC tonight and double check its oil...although I'm pretty sure it is. I haven't ridden the bike in over a month and it still looks shiny and wet, if it were gas i would assume it would evaporate and leave a normal dull finished top of the piston. And considering im losing so much oil, no matter what i need to pull it apart so it doesn't really matter right?

And as for the ring installation sheets, i followed all the instructions in my manual and did set up the oil rings at 90 degrees apart from one another on every cylinder and my manual has the compression rings at 180 degrees from each ring gap but the manual has one facing forward and one to the rear rather than one left and one right but i dont think thats an issue as long as they're 180 apart.

I plan on starting to take it apart tonight, but ill run a compression test first to just check off that the cylinders and rings/compression are not an issue.

Hopefully ill be down to the pistons tonight and ill upload some pics and see if we can figure out what went wrong.

thanks guys

If you look at the oil ring spacer you can see one is overlapped. That is wrong but a common mistake. That's why I posted it. If you're lucky, that's your problem.
Good luck.
Steve

I had new Wiseco rings and pistons installed by a reputable dealer when I was young, my bike used oil and smoked under hard acceleration, the culprits were the second piston rings fitted upside down.
You should just make out a small taper on the ring face of the second ring.
Don't change pistons unless they are stuffed badly, pistons really only hold the rings in place, its the rings that seal.
I now have MTC pistons in my Z1R which I'm happy with. I also have Wiseco in my FJ1200 which I'm also happy with (both sets were fitted by me).
I've had the head off a few times now and have never honed the bores or fitted new rings (70K kms since I rebuilt) once was because of a twisted crankshaft but thats another story

If it smokes blue then it is oil burning, black and sooty exhaust is too rich, I think either too much fuel or oil from a defective valve guide seal might prevent the rings sealing in one pot.

I'd do further diagnostics, and put more miles on it before stripping it -using only a mineral oil. Don't over-oil the bores,

Tyrell,
I get what you mean between blue smoke and black sooty but how would a too rich condition cause a significant loss of oil?
And a defective valve guild seal would most likely cause oil in cylinders 2&4 right? Not all the way over in cylinder #4