Sprocket size question

[jfoust]

So, as some of you know from another thread, I bought a Clone to replace an old Briggs 5HP Flathead (temporarily until I have time to restore the mistreated Briggs)... The more I tear into the kart, the more I realize how abused the whole thing was! Luckily it was cheap, and I don't mind a project.

I got the clone on there, got the chain aligned, and fired it up, only to find that it kept throwing the chain... Got to looking at it tonight and finally noticed that the sprocket is a little bent, so I'm sure that wobble is what's throwing it out of whack.

What's on there right now is a 10T centrifugal clutch and a 60t sprocket. The chain is pretty crusty too, so I'm thinking about replacing it and the sprocket. Surprisingly, the clutch is in good shape. I tore it down and checked the springs and shoes when I moved it over to the new motor and it looks decent.

So my real question here is should I stick with the 10/60 ratio? We'll primarily drive on the road in the neighborhood for the time being, and maybe a little (very light) off roading on a fire trail behind the house, so I'm not in desperate need of acceleration or top end - just a good compromise.

Thanks in advance for the advice!

 

[mike75925]

how heavy are you and the kart? that is the main thing. then do you want torque or speed. you said a good middle. are you leaving the clone stock?

 

[jfoust]

Not sure what the cart weighs but it's pretty hefty. Me and the kid are about 250lbs total. I won't be riding for long, just long enough to give some instruction and make sure nobody's going to die! Once I'm out of the picture it'll be more like 50lbs total.

I'm keeping the clone stock for now. Maybe down the road we'll start tweaking things, but for the time being it just needs to run! I can slap a new sprocket on it in a few years if needed.

 

[anderkart]

I think your 10/60 tooth gearing combonation will probably a great starting point for now. A new rear sprocket and chain sounds like a realy good idea too. I'd just add to make sure the gear/teeth on your old clutch aren't all wore out cause this could end up wearing out your new chain and rear sprocket sooner.

Also try to get some kind of strait-edge on there to confirm both sprockets are truly lined up. (or you could also stand the kart upright/or position it so you could use a Plumb-Bob hanging from 1 sprocket down to the other to confirm near perfect alignment)

 

[jfoust]

Anderkart - thanks for the advice. Hadn't thought about standing it up and using a plumb bob to get it lined up. I had been relying on my good old calibrated eyeball and a 3' bubble level (just because I know it's good and straight, not because it's a level) to get it straight.

I may replace the clutch while I'm at it too. What's another $40, right?

 

[1992suburban]

whats your tire size??

 

[jfoust]

I knew that would come up... Unfortunately I thought about it after I left the house this morning, so I won't know until this afternoon. It's a 6" wheel - I do know that much. Maybe about a 10" tire or so.

 

[bajagokart]

i would say that a 6:1 gear ratio is good enough for 10 inch tires! but if your sprocket is bent than you should get a new one lol and i would say that depending on what kind of kart your running, if its for street, use #35, if its offroad of any type i would say at least #40 chain

 

[jfoust]

Sorry, here's a pic of the kart. Nothing special (yet). Will update on tire size in a few hours when I get home. Thanks for the advice!

 

[bajagokart]

what size is that clone? the pic is blurry but it kinda looks like a 13 hp

 

[jfoust]

Sorry, the pic is from my cell phone... In very bright light it's amazing, but in anything else it doesn't pick up the shutter speed enough and everything's blurry! Anyhow, that's the 6.5 horse clone.

Just checked the tires and they're 13x5x6 on the back.

 

[Kaptain Krunch]

6:1 would be alright for that, How old is your son? i would be more worried about too much speed than anything, with that ratio you will be hitting around 23mph at full throttle and get there fairly fast.

 

[1992suburban]

good ratiio.. for that tire size.
clutch will last a good while.