Help with roper mini bike.

[Montini]

I need help with the model of tecumseh engine that will fit this bike. The guy I bought it from included a sears roto spader with a 6hp tecumseh engine. The engine has a 1 inch crank, I was going to turn the crank down to 3/4" but found out when I mocked the engine up that there is no way the clutch would line up with the rear sprockets. This is the 2 speed roper bike with 3 chains. I have the correct clutch but am having a hard time finding a good engine for it. A briggs would work if I install a bowl carb on it. Anyone know what the biggest tecumseh engine would be that would bolt in and allow everything to line up?

 

[1971_MB1A]

5 hp

 

[Brooklyn Bob]

Welcome to the minibike madness!

 

[creia]

My son installed a hot-rodded Tecumseh H60 (6 HP) in a "restomod" 2-speed Roper a couple of years ago. It had a ball-bearing supported 3/4" crank. Everything including the clutches and chains lined up perfectly. Your bike originally came with a 5 HP Tecumseh H50 which is the same overall block size as the H60. That bike was one of the most fun to ride an comfortable bikes we have ever owned.
Michael

 

[Montini]

When I put the tecumseh 6hp on the frame, the inside sprocket lined up with the block. Also the engine stuck out of the right side of the frame so far that it would interfere with the footpeg. Did this roper bike come with the h50 or hs50? The tecumseh 6hp that I have does not come close to fitting.

 

[Uncle mike]

Is this the correct brochure? Nice to see some more Tennessee folks on the forum. Welcome and enjoy

 

[capguncowboy]

Is this the correct brochure? Nice to see some more Tennessee folks on the forum. Welcome and enjoy

View attachment 95847

If we keep growing, we could potentially have the momentum to start a mini bike meet somewhere closer to home

 

[creia]

When I put the tecumseh 6hp on the frame, the inside sprocket lined up with the block. Also the engine stuck out of the right side of the frame so far that it would interfere with the footpeg. Did this roper bike come with the h50 or hs50? The tecumseh 6hp that I have does not come close to fitting.

You state you have a "Tecumseh 6 HP". Which MODEL? Post some photos of your engine including having it mounted in the frame so we can look at it. My son's was a H60 and fit the frame w/o any problems whatsoever and all of the chains lined up from the engine clutch to the 2 speed jackshaft perfectly.
Michael