R100/7

rockymandc · 10-05-2012, 09:01 PM

Hello - I'm completely new to this forum. I just picked up a winter project, 1977 R100/7. The only good news so far is I paid very little for it and the ignition switch has a key in it that turns. Short history is that the bike has been sitting 5+ years and most of that outside under a tarp. I got it for a song - but the jury is still out on feasibility.

Immediate question is how much rust can be tolerated in the cylinder wall, and can it just be handled with a hone job or is it a must that they be bored and refit with new pistons ?? Currently there is cresent shaped spot on the low side were some water pooled at the outbound end of the cylinder.

Also, this machine was dual plugged.

Thanks

Matt

Rob Farmer · 10-05-2012, 11:50 PM

I'd knock the rust off the bores with light emery cloth and wires wool and then run it with the pistons and rings you have. get it settled in and running and then worry about tolerences. it'll probable smoke badly when you fire it up as oil tends to sit in those grooves, depending on the overall wear in the bores you can get away with with quite a bit of honing before you need to rebore and fit new pistons.

Mista Vern · 10-06-2012, 12:42 PM

What Rob said. See what other horrors you find before putting too much into it.

10-05-2012, 09:01 PM	#1
rockymandc ^OP n00b Joined: Oct 2012 Location: Pacific North West USA Oddometer: 4	R100/7 Hello - I'm completely new to this forum. I just picked up a winter project, 1977 R100/7. The only good news so far is I paid very little for it and the ignition switch has a key in it that turns. Short history is that the bike has been sitting 5+ years and most of that outside under a tarp. I got it for a song - but the jury is still out on feasibility. Immediate question is how much rust can be tolerated in the cylinder wall, and can it just be handled with a hone job or is it a must that they be bored and refit with new pistons ?? Currently there is cresent shaped spot on the low side were some water pooled at the outbound end of the cylinder. Also, this machine was dual plugged. Thanks Matt

10-06-2012, 12:42 PM	#3
Mista Vern Knows all - tells some. Joined: Dec 2005 Location: McMinnville, Oregon Oddometer: 12,874	What Rob said. See what other horrors you find before putting too much into it. __________________ Remodeling. Please check again later.

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10-05-2012, 11:50 PM	#2
Rob Farmer Beastly Adventurer Joined: Aug 2002 Location: Loughborough, Leicestershire. England Oddometer: 3,733	I'd knock the rust off the bores with light emery cloth and wires wool and then run it with the pistons and rings you have. get it settled in and running and then worry about tolerences. it'll probable smoke badly when you fire it up as oil tends to sit in those grooves, depending on the overall wear in the bores you can get away with with quite a bit of honing before you need to rebore and fit new pistons.