Extending a Crankshaft?

[John S]

So still working on my 1966 Lil Indian. Several months ago I found a age appropriate B&S 5hp engine. I was thrilled! Fast forward to this week when I was getting it ready for installation... the crankshaft that extends from the engine on which the clutch mounts is only 1 1/4" long... not 2+" long. Help! Do I have any options?

- Can I have a small piece of crankshaft welded onto the end so it will accept a clutch?
- Is there a "skinny" clutch that will work on just a 1 1/4" long shaft?
- Other options?

:no::doah:

 

[125ccCrazy]

you can use a 3/4 jackshaft or a section off an old crank, drill through the new section with a tad smaller than 5/16 drill bit so a 5/16 bolt fits snug and then use a long bolt to go through the extension into the crank..cut the extension so it's a tad shorter than the distance from the crank end to the outside of the clutch so the ext is inboard to the clutch maybe a 1/16", use a fender washer on the bolt and bolt the clutch on solid.. it's either than or replace the crank, personally I'd swap cranks out.

 

[massacre]

Can you put a sprocket on the crank and use a clutch on a jackshaft?

 

[John S]

you can use a 3/4 jackshaft or a section off an old crank, drill through the new section with a tad smaller than 5/16 drill bit so a 5/16 bolt fits snug and then use a long bolt to go through the extension into the crank..cut the extension so it's a tad shorter than the distance from the crank end to the outside of the clutch so the ext is inboard to the clutch maybe a 1/16", use a fender washer on the bolt and bolt the clutch on solid.. it's either than or replace the crank, personally I'd swap cranks out.

That's a brilliant idea! I'll take a look at that. Thanks!

 

[John S]

Can you put a sprocket on the crank and use a clutch on a jackshaft?

Yes, I thought about that. Thanks for the reply. I'm trying to keep it as original as possible.

 

[massacre]

Yes, I thought about that. Thanks for the reply. I'm trying to keep it as original as possible.

Ok I didn't know if you were trying to keep it original or not. Sorry!

 

[John S]

Ok I didn't know if you were trying to keep it original or not. Sorry!

No Problem! :thumbsup:

 

[bpoirier]

I have a similar 5hp engine. I just switched cranks from another 5hp with the longer shaft.

 

[John S]

I have a similar 5hp engine. I just switched cranks from another 5hp with the longer shaft.

The engine that came with it is a Tecumseh and I'm using a B&S, so no extra B&S engine around.

 

[bpoirier]

The engine that came with it is a Tecumseh and I'm using a B&S, so no extra B&S engine around.

I've got a couple of extra 5hp cranks. If you want one. I just need to know if you have the early small bearing or later big bearing crank. I can hook you up cheap.

 

[John S]

I've got a couple of extra 5hp cranks. If you want one. I just need to know if you have the early small bearing or later big bearing crank. I can hook you up cheap.

Thanks bpoirier! I just sent you a message.