Hi folks,
Been on the site for a bit, decided I’d share my bike.
Started life as a 71 Rupp frame, forks and swing arm. Dubbed the “Spitfire” because it would backfire pretty good with the first muffler so from there the name stuck.
We do a lot of ice racing in the winter so I needed something to compete with the other rupps on the pond.
Ended up painting it with some Dodge Viper red that I had leftover from a car project, I printed up some custom Rupp decals with my own twist on them. Had to make a few modifications to make the Hm100, what I called the “Dwarf Star” to fit. The spark plug is very close to the frame so changing it requires pulling the tank. Started with a Points Ignition Hm100 which was the 333cc block with star rod, 425 lift cam. Fueled with a D-slide carb. Stock exhaust that was hogged out. it runs a Tav20 torque converter, comet belt with no problems at all. Additionally I was able to find an electronic ignition box that utilized the points coil without the condenser and points which allowed for higher RPM and easier pull starting with the 425 lift cam.
After a bunch of racing the old hm100 It developed a ton of blow by and lost compression. I was able to buy a new star block, cam, rod and piston for under $150 Locally. I did have to install a decompression with the star cam Which I like more than the 425 cam so there was some head machining to make that work properly on a pull start bike.
From there I made some steel extensions Out back to make the bike a little longer. Machined an adapter for Some hydraulic front forks. Some Yamaha rear shocks.
There’s so much I’m forgetting at this point, but I’d like to keep this post updated as I modify the bike more.
Mock up before paint
Finishing up the initial Assembly How it looks today with the star.
the bike at this point has some mild modifications, larger exhaust piping, RLV muffler, billet tappet cover. Some other small goodies.
It’s a handful but it’s a blast to ride
Been on the site for a bit, decided I’d share my bike.
Started life as a 71 Rupp frame, forks and swing arm. Dubbed the “Spitfire” because it would backfire pretty good with the first muffler so from there the name stuck.
We do a lot of ice racing in the winter so I needed something to compete with the other rupps on the pond.
Ended up painting it with some Dodge Viper red that I had leftover from a car project, I printed up some custom Rupp decals with my own twist on them. Had to make a few modifications to make the Hm100, what I called the “Dwarf Star” to fit. The spark plug is very close to the frame so changing it requires pulling the tank. Started with a Points Ignition Hm100 which was the 333cc block with star rod, 425 lift cam. Fueled with a D-slide carb. Stock exhaust that was hogged out. it runs a Tav20 torque converter, comet belt with no problems at all. Additionally I was able to find an electronic ignition box that utilized the points coil without the condenser and points which allowed for higher RPM and easier pull starting with the 425 lift cam.
After a bunch of racing the old hm100 It developed a ton of blow by and lost compression. I was able to buy a new star block, cam, rod and piston for under $150 Locally. I did have to install a decompression with the star cam Which I like more than the 425 cam so there was some head machining to make that work properly on a pull start bike.
From there I made some steel extensions Out back to make the bike a little longer. Machined an adapter for Some hydraulic front forks. Some Yamaha rear shocks.
There’s so much I’m forgetting at this point, but I’d like to keep this post updated as I modify the bike more.
Mock up before paint
Finishing up the initial Assembly How it looks today with the star.
the bike at this point has some mild modifications, larger exhaust piping, RLV muffler, billet tappet cover. Some other small goodies.
It’s a handful but it’s a blast to ride
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