This site started out as a way to track a BMW / Jupiter Sidecar motorcycle project. It has gone in many different directions since its' conception. From motorcycle projects, to personal stories, opinions and family histories. I log most of our boring motorcycle riding adventures and experiences. I have completed my "R100S/6" build and changes are on-going.
I retreived the newly rebuilt cylinder heads in San Diego yesterday so decided to assemble the engine top end this morning. When I originally pulled the R100S engine apart, years ago, it had cylinder base metal gaskets installed. Unfortunately I tossed them thinking that new ones would be used. I then found out that the base gaskets were not used on these engines. The later engines had an "o-ring" groove on the cylinders for sealing. This engine had no o-ring grooves so sealant was necessary to seal the cylinder to the engine. I want to reduce the engine compression a bit so I purchased a pair of earlier base gaskets and then trimmed down the interior diameter to fit over the engine cyliders. All I have is a small Dremel type tool so I spent probably an hour on each gasket, trimming down the interior diameter to fit over the cylinder base. Hopefully the base gasket will not reduce the compression too much. I saw signs of detonation on one piston so reducing the compression should hopefully make the engine run a little cooler and get rid of any "pinging".
The base gasket in place prior to cylinder head installation.
I cleaned up the pistons / ring grooves well before installing them in the cylinders. There are also a couple of o-rings on two of the cylinder studs. I made sure they were properly in place before installing the heads. I previously had pinched one of the o-rings causing a minor cylinder base leak.
Brand new Black Diamond Valves, Valve Seats and o-ring valve guides.
I actually spent more time modifying the base gaskets than it took me to assemble the engine top end.
I then turned my attention to the clutch assembly. I ordered a set of special bolts needed to back off the pressure plate assembly. Once the clutch came out I was in awe that it even worked. Two big chuncks were missing from each side. The pressure ring / pressure plate are grooved and worn down. This unfortunate developement will require replacing everything in the clutch assembly....to the tune of $500.00 or so.....
Suprisingly the fly wheel has been lightened and balanced.
So...we'll be digging through old dirty shipping containers tomorrow to unearth an old WW2 motorcycle and sidecar...anyway that is according to the present owner.
I have no idea what we will find....or even if it actually is a WW2 German motorcycle.
Apparantly this bike / sidecar was sitting in an old semi trailer for eons, where the previous owner stashed it. The semi trailer was an on old 40's "art deco" looking rounded affair that someone wanted so bad that they purchased a shipping container and hauled it to the property to replace the old "deco" semi trailer.
At some point the sidecar was removed from the bike so it would fit in its' storage space.
I talked with the owner this morning and he said we might have to do a little digging in the storage containers to find everything.
Sounds like fun to me!
Maybe it is an old Zundapp KS800?
Or maybe a old BMW R12?
Ooohhhh...or maybe an R75?
Or maybe an old Zundapp KS750?
Tomorrow will tell.......I'll have my camera and notebook handy to record serial numbers....or maybe I'll need my Chinese / Russian Dictionary.....