This bike is a blast to ride. Fast and zippy for a small bike but next to a real motorcycle, you realize how slow you are going! The restoration took about a year. I had help rebuilding the engine and transmission. A friend Adam helped me weld the bump onto the seat. Chrome, powder coat and paint were all locally sourced. Custom YSS shocks. Assembled by me. The only bummer is that I could not find the correct street Bridgestone tires to put on the bike.
Fingers crossed this exhaust works. It is from a 1930’s R12 BMW. I had a larger inlet welded to mate with the R75 headers. I hope they do not restrict power in any way or make the tuning of the engine difficult.
The headers and mufflers connect OK and luckily the brackets on the mufflers line up pretty close to the exhaust hanger area on the R75/5 frame.
To connect the muffler to the frame, I had to make some custom brackets to attach the muffler.
I made a test set out of aluminum and everything worked out OK. My holes were slightly off but I corrected for that later.
I took my brackets and a pocket full of cash to a local welding and machine shop. He replicated my brackets with stainless steal and put the holes in the correct place as per my instructions.
Stainless steel should withstand the heat, elements and keep its shape. I worried that the aluminum brackets I made would not do any of the above.
One step closer to starting this baby up!
Due to relocating the battery I had to make some custom battery cables. One has to run from battery (located in the tail section of the seat) to the starter and the negative cable will most likely ground on the transmission near the shifter instead of at the speedometer cable.
When i got the seat pan and the tail piece(see previous post), I immediately began to wonder how to mount the two together. BMW’s R100S seat and cowl is a great design and works well with the hinges. But this is a Short Wheel Base model and we are going with the fiberglass tail piece. The tail piece mounts to the subframe through the saddle mount bag loop at the rear of the subframe and a small ‘tang’ that goes into the main frame tube.
The suggestions I got for mounting the seat pan to the tail piece were:
Upholstery with snaps (no thanks)
And then finally… i found out about Well Nuts. BINGO!
Well nuts seem perfect because they act as a thin rubber buffer between the to parts. Also when you tighten them they pull the pan snug onto the tail piece.
To do the job, you are going to need about
– 7 Well Nuts
– 6/32 screws to match the Well Nuts – about .75 inches long
– Fender washers for the Screws
– and a 5/32 and 5/16 drill bit.
The first step was to mark 3 holes to mount the rear of the seat pan to the tail piece.
The holes are drilled with the 5/32 bit. Just big enough to get my screws through.
The Well Nuts in the photo will eventually live in the seat pan.
Then snug up the upholstered seat onto the tail piece as best you can, and mark through the holes.
I started by drilling holes into the seat pan with the 5/32 bit. BE CAREFUL. DRILL SLOW. If you ram the drill bit through the seat pan, it will go through the other side and ruin the upholstery.
Now that the seat pan is attached to the tail piece, I marked 4 additional holes for some extra reinforcement.
NOTE: Make sure these holes do not conflict with the subframe cross member that contains the fender mounting bracket.