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What do you think of these cylinders?

Posted: Tue Dec 07, 2010 5:25 pm
by Rapid Dog
1981 R100RS with 55K

This bike is having the heads rebuilt/replaced.
I took a look at the cylinders. They look pretty good, maybe even had the rings done not so long ago...
I can see hone marks in the cylinders and they have no ring ridge at the top whatsover. Piston tops look rather clean.

I thought I'd re-ring it but now I'm thinking I'll just pass and button it up when the heads get back.
Install new pushrod seals and call it good.

Appreciate any opinions and insight on this.
The bike smokes just a bit on startup. Previous owner claimed it uses about 1 quart every 1500 mile or so.

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Re: What do you think of these cylinders?

Posted: Tue Dec 07, 2010 5:31 pm
by Major Softie
Check the ring gap before you make any decisions

Re: What do you think of these cylinders?

Posted: Tue Dec 07, 2010 6:42 pm
by mattcfish
Major Softie wrote:Check the ring gap before you make any decisions
Remove the top ring (carefully). Push it into the cylinder with the piston. Measure the gap at various spots in the cylinder.
If the gap doesn't change more than the specified (check the book or Duane's sight) amount I wouldn't worry about the cylinders. If those are Nikasil (which they appear to be), I wouldn't worry about the cylinders. If the gap is not too large (check the specs.) then the rings are probably OK.

Re: What do you think of these cylinders?

Posted: Tue Dec 07, 2010 6:46 pm
by Scot
These damn snowflakes are driving me NUTS!

Re: What do you think of these cylinders?

Posted: Tue Dec 07, 2010 6:59 pm
by Garnet
Scot wrote:These damn snowflakes are driving me NUTS!
????????????????????????????? :?

Re: What do you think of these cylinders?

Posted: Tue Dec 07, 2010 7:54 pm
by mattcfish
Scot wrote:These damn snowflakes are driving me NUTS!
I see them too. Am I crazy as well?

Re: What do you think of these cylinders?

Posted: Tue Dec 07, 2010 11:46 pm
by She'llbe
mattcfish wrote:
Scot wrote:These damn snowflakes are driving me NUTS!
I see them too. Am I crazy as well?[/quote
Probably yes.

Re: What do you think of these cylinders?

Posted: Wed Dec 08, 2010 3:35 am
by gertiektn
Yeah, like a blizzard coming in.. maybe they are viro-bots on the look out..
MAYBE, it the Chinese Govmt... checken out our site.

Not only that the side bar and curser is nutty.

Oiling cylinder.. build up of carbon.. it points to checking the roundness of the cylinder, checking the rings for breaks, and checking cylinder fit and ring specs. You need to do a complete job and do a complete check to correct the issues.

Doing it right, is not always the easy or cheap way. Bite it and do it right, and if you don't know how.. find someone who does.. save your money and pay a fair price for competent work done.

The completed result is a sweet engine.

jim, Ketchikan, Alaska

Re: What do you think of these cylinders?

Posted: Wed Dec 08, 2010 2:39 pm
by John Falconer
Snow - yes, at least with IE8 and IE9. Weird little box-like elements from top right to lower left.

As to the cylinders and pistons - they're fine, perfectly normal as I would expect. Do check ring end and side gap/clearance but that's not always indicative of results. If you weren't burning oil I'd just slap on the heads and go ride.

Re: What do you think of these cylinders?

Posted: Wed Dec 08, 2010 6:29 pm
by mattcfish
John Falconer wrote:Snow - yes, at least with IE8 and IE9. Weird little box-like elements from top right to lower left.

As to the cylinders and pistons - they're fine, perfectly normal as I would expect. Do check ring end and side gap/clearance but that's not always indicative of results. If you weren't burning oil I'd just slap on the heads and go ride.
What he said.