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Sschuettenberg

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Hello there, new to forum but frequent visitor.

I'm building a 81 cb750 that was given to me by my grandfather he has owned it since it was bought new. The bike came with a dohc motor and has its flaws. For the short time I'm looking to drop an 78 sohc into the frame and work on the dohc motor during the winter.

I've done some research and turns out the motor will bolt into my frame but the motor does not come with its set of carbs. My main concerns are limited but valid. Will I need a new wiring harness and will my dohc carbs work on the sohc motor, I'm not very confident working on carburetors so any help is greatly appreciated.

Thanks in advance
 
Flawed research, they don't bolt in. And the carb issue is much worse, they don't fit in so many ways you'd have to redesign the entire thing to make it work.

SOHC engines use a dry sump tank, the DOHC is wet sump, you have no separate oil tank.
 
So a SOHC motor will not work on my frame is what your saying? It seems I should put my efforts into rebuilding the original motor.
 
The actual bottom end cases will go in without a lot of trouble but you have no carbs and no way is that dohc carb set going on the early one. Then you have the exhaust issue to deal with, no way are they the same. The charging system totally different too, you WILL be butchering a harness up if you don't have one. Electronic ignition used on the dohc thinking not on the sohc.

We were just today looking at someone who did it on the dohc custom site and brother what a butcher job, and no evidence it will even run based on how ragged it looked. A real hack job. Guy had a sohc bottom with a dohc top end and we were wondering how he got past the two timing chains being different, one is morse hyvo and the other normal chain like drive chain. Would have had to machine crankshaft somehow. Problems there with the two different oil pumps too, I'd be willing to bet it lasts five minutes after starting it and no more.

You can get one together, that doesn't mean squat.
 
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