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Old 07-26-2012, 10:36 AM   #1
italiano OP
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Location: South of the border
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Bore jugs advice

After a few world with Carl, he suggest that is very difficult to bore r 100 cylinder, so after my last attemp of install oversized rings failed, my last chance before buy new cylinders (i cannot find them is a 78 r 100 europeans specs engine, i think with big valves) is to send them to a bore service and new pistons in Rennsport facilities.
What would you do?
The moto bins alternative (all new) is very expensive over 1000 usd plus shipping.
I cannot find new cylinder on max bmw pages, were to find them??
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Old 07-26-2012, 10:42 AM   #2
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Two thoughts

If they aren't too far out they can be Nikasil plated then honed back to size. I don't know who is doing this work, you could try Cycleworks.

You could also check the prices to have your current jugs resleeved. I would call Bore Tech in Ohio for that.

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Old 07-26-2012, 11:39 AM   #3
italiano OP
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Just call them it wil be more than 600 if you take the shipping cost, do you think there is a cheaper alternative?
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Old 07-26-2012, 11:41 AM   #4
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I stated it is not so much as being difficult, but that it needs to be done properly, carefully and is not always the best option.

Cycleworks does not specialize in cylinder rebuilding/restoring. There are facilities like Bore-Tech and others that do them day in and day out to high standards.

A large inventory of used airhead parts can be found at places such as Martindale Cycle Works


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Old 07-26-2012, 11:49 AM   #5
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Location: Atlanta, GA, USA
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In my opinion ... and I've been down this road before ... I would not overbore. I would look online and buy a Seibenrock kit, or find someone with a set of R100 cylinders and pistons on the shelf. Or just look around for a used set of Nikasil cylinders and pistons. They aren't that rare ... and the $400-$500 you spend on them will be the same as purchasing new pistons, rings, and getting a machinist to overbore.

I took my oversize pistons, to a BMW specialized machinist ... and he did it. 5K miles later I had some issues with the gap between my pistons and cylinders to the point that my rings never quite sat properly. Nothing but trouble.

Also once you go over-bore the prices for rings / pistons, go way up ... supply and demand. Demand is actually low, and supply is made to order.

I will never do that again. Just my personal perspective of course.

PS - The amount I paid for 'new' overbored pistons, + rings, + labor to overbore the cylinders, + breakin time, + new (old) Nikasils and pistons, I could have bought the Seibenrock kit outright and had money to spare.
Fred <|> Need an Airhead Part? .... I May Have It!
'85 BMW R80RT G/Sified <|> '73 BMW R75/5 LWB <|> '94 MZ Silver Star Hack
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Old 07-26-2012, 12:15 PM   #6
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+1 Go nikisil. Way better on so many levels. Spend the money right. It's better than wasting it! I just got new nikisil cylinders and pistons for my own bike. I have at least one set of lined 1000cc jugs laying around. I just realized that I didn't even consider using lined cylinders. For free!
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