250r Kart (formerly Briggs Kart)
- Thread starter newrider3
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Picked up a rad, full wiring harness, pipe, and intake/reed cage. Also got a brand new Doma silencer (built for '01 YZ but it fits) for **** cheap. Ended up having to use the sh!t Miller 185 at school for part of the motor mount, so I had to grind down a bunch of porosity filled welds. Used the TIG for the tabs today though, so that came out nice. Also chopped up an old piece of tube from a swingset or something for a shifter.
jr dragster T
New member
Did you wire wheel that motor?
Kaptain Krunch
Pro Junk Collector
Sweet, that things pretty sexy.
Are you gonna reinforce those shock towers?
Are you gonna reinforce those shock towers?
Kenny_McCormic
Kartless....
Those shock towers really need some gussets or something.
bajagokart
New member
dude that thing is looking amazing! nice work!
So I have a couple questions for you guys that deal with bikes/atv's often. I went and picked up a sprocket for the motor today, and took it to a hardware store to look for jackshaft sprockets. The teeth on the #50 sprockets in the store are wider than the teeth on the motor sprocket. What type of chain do these things use? Can I use standard #50 industrial chain?
Also, what kind of gearing should I run? Every time I try to stick my specs into a speed calculator I get some screwed up numbers. The quad originally had 13:38 gearing, so I was thinking of going something like 13:13 on the jackshaft, then 13:40 on the final ratio. Should I run something lower? Or should I stick with the stock ratio?
Also, what kind of gearing should I run? Every time I try to stick my specs into a speed calculator I get some screwed up numbers. The quad originally had 13:38 gearing, so I was thinking of going something like 13:13 on the jackshaft, then 13:40 on the final ratio. Should I run something lower? Or should I stick with the stock ratio?
dpaxson
New member
it probably uses 520 chain. 50 and 520 have the same pitch and roller diameter but the 50 is wider. I wouldn't use 50 in a 520 sprocket because there will be a lot of side to side slop. you could machine down the sides of a 50 sprocket to make it fit 520 chain. also for the gearing you have to account for the gear reduction of the transmission. try to find the ratio for the highest gear to calculate top speed.
modelengineer
Lord of the noise
There is no problem using 530 chain on a 520 sprocket, so I can't imagine there's an issue running #50 chain on a 520 sprocket. It has a little extra side play, true, but it isn't a problem.
As for the ratio, I'd go as low ratio as you can. Your tyres are smaller than the bikes, meaning it's already a slightly lower ratio, but even lower would be better imo.
I went from 16-39 on the bike, to 14-50 with the same size tyres. If I had found a 60 tooth rear sprocket and a 13 tooth primary I would have used them, no question. In my experience it's impossible to get too low a gear ratio, but with a jackshaft it might be different because you can get a seriously big reduction that way.
As for the ratio, I'd go as low ratio as you can. Your tyres are smaller than the bikes, meaning it's already a slightly lower ratio, but even lower would be better imo.
I went from 16-39 on the bike, to 14-50 with the same size tyres. If I had found a 60 tooth rear sprocket and a 13 tooth primary I would have used them, no question. In my experience it's impossible to get too low a gear ratio, but with a jackshaft it might be different because you can get a seriously big reduction that way.
Kaptain Krunch
Pro Junk Collector
50 chain is actually slightly narrower than 530 chain. I tried using a #50 master link with 530 chain and had to file the sides of the 530 chain slightly for the master link to fit over.
I would suggest just using the right chain and sprockets.
What size tires did the quad use? If yours are about the same size, i would gear it just slightly lower to make up for the extra weight of your kart.
With my kart, i ran a 2.33:1 ratio between tranny and axle (IIRC), and the bike ran a 3:1 ratio, however i'm running 15" tires, and the bikes were 26" in diameter.
I would suggest just using the right chain and sprockets.
What size tires did the quad use? If yours are about the same size, i would gear it just slightly lower to make up for the extra weight of your kart.
With my kart, i ran a 2.33:1 ratio between tranny and axle (IIRC), and the bike ran a 3:1 ratio, however i'm running 15" tires, and the bikes were 26" in diameter.
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