20-HP Kohler V-Twin (CH620) with 1-7/16" shaft—Is it worth the effort?

[ouchmytoe]

I was hoping to use a Kohler v-twin in a Chinese cross-kart build (think old Trail Master) but have run into issues sourcing a 1-7/16" bore centrifugal clutch. As I was lurking in the forum, I noticed a thread posted last year about about the same thing; it looked like the consensus was to (somehow) reduce the shaft diameter to 1". So, a couple of questions: (1) Has anyone made use of one of these engines? (2) Would a machined "reducing coupler"-type setup be feasible? (3) Would a 1" intermediate shaft be feasible? (e.g., 1:1 link from 1-7/16" shaft to 1" exposed shaft with clutch, which is then linked to the drive axle) (4) Snowmobiles can have big clutches, but in my search so far, they all need tapered shafts; has anyone run across a snowmobile with a 1-7/16" straight shaft? I hesitate to try selling the v-twins (I actually have 2 nearly identical engines) because I'd hate for someone to run into the same issue I've had. Any ideas are appreciated!

EDIT: I'm also looking for a 1" Kohler crankshaft to swap into these engines—so far, I'm lost.

 

[panchothedog]

Maybe I'm over simplifying here, but I think pulling the crank out, taking it to a machine shop and having the exposed part turned down to 1" O.D. would be your best bet. Then have a 1/4" key way cut into it. Might be a couple of hundred dollars of machine shop labor. But a 20 hp.engine is well worth the investment. Especially a Koehler V twin. Good tough well proven industrial engine.

 

[Denny]

Or your easiest solution like you said sprocket-chain-sprocket to a 1” jackshaft. But I would use a 780 Comet CVT. I don’t think a centrifugal clutch would hold up. Maybe a Noram industrial centrifugal would but expect to pay $500-$1,000.

 

[ouchmytoe]

Or your easiest solution like you said sprocket-chain-sprocket to a 1” jackshaft. But I would use a 780 Comet CVT. I don’t think a centrifugal clutch would hold up. Maybe a Noram industrial centrifugal would but expect to pay $500-$1,000.

"Jackshaft"! So that's what that's called. Thank you sir!

 

[ouchmytoe]

Maybe I'm over simplifying here, but I think pulling the crank out, taking it to a machine shop and having the exposed part turned down to 1" O.D. would be your best bet. Then have a 1/4" key way cut into it. Might be a couple of hundred dollars of machine shop labor. But a 20 hp.engine is well worth the investment. Especially a Koehler V twin. Good tough well proven industrial engine.

Thank you! I was hesitant to rip into the engine's inner guts without someone besides me believing it a reasonable course of action. I'll shop for estimates this week.

 

[Darren]

If you have room, jackshaft with fully enclosed chain cover, this is spinning all the time the engine is running.
Don't touch the engine, if it runs and no need to open it up, then don't.