1977 R100s cylinder sleeves

schrader7032 · Post by **schrader7032** » Fri Dec 12, 2008 7:23 am

Joe -

So you're saying that going past the 2nd oversize won't get rid of the pitting? The R100s were stretching the limit as far as "meat" in the original liners. If you go too far, you'll possibly get warping in the walls where the tunnels are for the four head bolts.

From reading postings from a couple of "gurus" on the Airheads list, they don't recommend trying to resleeve R100 bores. It's dicey at best and there might end up being heat transfer problems. Heat's a big killer on the larger engines. Don't know where you are, but you could check with Ted Porter out in NorCal, Scotts Valley, at http://www.beemershop.com/. He has access to good machinist and is a good Airhead wrench.

Ted and others say the way to go is the Nikasil route...it'll be more expensive than a resleeve or rebore. Finding used parts would reduce the costs. You'll need new jugs and rings. You might even need new pistons because the head in your bike might have a squish band with could conflict with other pistons. This site has some pictures on various piston shapes - http://moragafalconers.org/bmw_pistons/.

Nikasil should be bulletproof for many, many miles. I think what people are saying is that resleeving is a "for now" solution but it will have to be fixed again sooner rather than later.

Give Ted a call and see what he suggests.

Edit: I just rememberd Bore-Tech. A lot of the /2 people have used their services to bore and apply a carbide treatment to the bore for longer life..similar to Nikasil. They list resleeving on their website. Might be worth a call, too.

http://www.bore-tech.com/

Kurt in S.A.

joekelly · Post by **joekelly** » Sat Dec 13, 2008 11:32 am

Thanks Kurt for the helpful info. I'm from Pa and I' ll keep you posted.

schrader7032 · Post by **schrader7032** » Sat Dec 13, 2008 1:43 pm

PA? Do you know about Tom Cutter's shop in Yardley, over by NJ? He's also a very good Airhead wrench. His website is:

http://rubberchickenracinggarage.com/

Kurt in S.A.

joekelly · Post by **joekelly** » Tue Dec 16, 2008 8:51 pm

Kurt, thanks again for the info. To keep you updated I found a pair of sleeeves online and a machinist guru at a resonable price. I here what your saying with the band aid but I already opened a can of worms with rebuilding the carbs and gas cocks, new battery, fluids ect. and still haven't fired it up yet. The previous owner said the only thing he knew that was a problem was a clicking noise in the rear drive which I haven't even got to. But no worries, this has been a blast digging into. keep you posted. Joe in Pittsburgh (GO STEELERS!!!)

Dyefrog · Post by **Dyefrog** » Tue Dec 23, 2008 11:54 am

You can try this site too. They sometimes have the part you're looking for
http://www.ibmwr.org/market/adlist.php?cat=aps&page=2[/url]

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:52 pm

Hi folks, just purchased a " 77" R100s that has been in storage for ten years , my first street bike-always loved the old things, anywho, after getting her home iv'e found that the one piston was locked up due to a little gas dripping into the cylinder and pitting it out. Well, got the thing all apart and found a machinist to bore it out but he thought re-sleeving the cylinder was the answer due to spec allowance. Fine and dandy, but I can't find the sleeves anywhere. Can any of you Beemer journeyman help this airhead virgin out? Thanks in advance

Vintage BMW Motorcycle Owners