sprocket gearing

[kartsandatvs]

Hello forum, I am a newbie, have had experience with track karts using the 160gx 5.5 hp honda engine with a 4 to 1 relation which is really an 8 to 1 because of the wet clutch (2 to 1 relation ), I am now installing a clone 6.5 hp harbor freight engine on an old 3 wheeler, using a jacksaft to obtain a 10 to 1 relation and also because the kawasaki 3 wheeler uses #520 chain and the clutch uses #40 chain, so the jackshaft would have both the # 520 and the # 40 srockets ,my question would be what do you think of a 10 to 1 relation with 18 inch diameter rear tires and also what 3/4 centrifual clutch would you advise me to get good price and good working clutch, I know 3 wheelers are very instable so its mainly torque and not speed I am looking for I think, thanks

 

[OzFab]

I think that setup should work fine but, it all depends on how big/heavy the 3 wheeler is; will a 6.5hp engine be strong enough? What was the original engine?

 

[landuse]

I would have to agree with Fabroman. The 10:1 should be OK with those tyres. I would go for it, and if it is not working out for you, you can always change one of the jackshaft sprockets to gear lower.

 

[kartsandatvs]

Thanks for your replies, the 3 wheeler had a 200 cc 2 cycle engine, the planned gearing would be 10-20-10-50 to get the 10 to 1 relation, maybe 10-30-10-50 would be a better starting point to get a 15 to 1 relation. Any good lasting 3/4 inch, 10 tooth centrifugal clutch in mind ? Thanks again

 

[landuse]

Thanks for your replies, the 3 wheeler had a 200 cc 2 cycle engine, the planned gearing would be 10-20-10-50 to get the 10 to 1 relation, maybe 10-30-10-50 would be a better starting point to get a 15 to 1 relation. Any good lasting 3/4 inch, 10 tooth centrifugal clutch in mind ? Thanks again

All of the name brand clutches are pretty good. Max torque is one that comes to mind

 

[OzFab]

...& you're in luck, #40 3/4" clutches come in 10tooth

Going from a 200cc 2 stroke to a 200cc 4 stroke may sound like an even swap but, beileve me, it's not. Do some research on the original engine, I can almost guarantee it had a lot more than 7hp...

Knowing that, IMO, you may be better off with a slightly more expensive 4 stroke pit bike engine

 

[kartsandatvs]

Hello guys, tried the 10 to 1 ratio on the 3 wheeler this weekend and it worked great, I have pictures and a small video but dont know how to post them. I also noticed something else the camshaft on the 6.5 hp honda clone measure .7495 inches but the inner hole on the max torque clutch measured more than .7500 there was a gap that i was able to fill with 2 layers of a beer aluminum can, the gap was filled 90%. Please let me know how to post pictures and video, thanks

 

[philip metzner]

The clutch should have fit perfect on a .7495 crank. You must have got a clutch with a bore other than 3/4 inch.

 

[OzFab]

3/4" = 0.75" = 19.05mm. It's possible your shaft is only 19mm making a difference of 0.05mm or 0.002". If the shaft is slightly worn, that would, obviously, make the gap larger...

To post pics, read this. Vids need to be uploaded to a third party site like youtube then post the link here...

 

[landuse]

3/4" = 0.75" = 19.05mm. It's possible your shaft is only 19mm making a difference of 0.05mm or 0.002". If the shaft is slightly worn, that would, obviously, make the gap larger...

To post pics, read this. Vids need to be uploaded to a third party site like youtube then post the link here...

THIS post is also quite informative

 

[kartsandatvs]

Hello guys, yep the hole on that max torque was a bit bigger, the thickness of the aluminum can is 3.5 thousands so the 2 sleeves that I rapped around the camshaft actually increased the shafts diameter by 14 thousands, anyway there is no gap anymore, thought it would be a good idea to share that with you. let me ask my sons how to include pictures on a video and i will send you the link. Have a great day and thanks for your replies , and yes the engine is brand new with a measurement of .7495 inches, i think it was machined perfectly.

 

[kartsandatvs]

Ok guys here is the link sorry for the mess, and thanks for your help

http://youtu.be/5pKI-VkGxtg