When does chain size become a factor?

[The.MiniTard]

I have a bunch of #35 clutches and sprockets, I recently let go of a vintage frame and a acquired a new roller that came with a 31 tooth 40/41/410 sprocket.
A couple problems arose:
1: Gear ratio would be too low, requiring me to have to purchase a jackshaft kit and then go to my buddies house and use the welder(which....isnt gonna be safe because i recently welded a scrub brake on and uhhhhh yea)
and
2: The sprocket is so small that the chain would hit the scrub brake(no i didnt weld this one) bar type deal.

So, would it be nescessary to use a bigger size chain because i have a 4 hp engine or will a #35 work fine?
At what power levels do you need to begin to think about using a bigger size chain?

 

[Baja_brandon96]

#35 is plenty strong if you get quality chain, unless your making obscene horsepower. That said, ive been buying Donghua chain in 10ft lengths on ebay and amazon for all my motorised toys, works great and doesnt really stretch. Great price too.

 

[The.MiniTard]

#35 is plenty strong if you get quality chain, unless your making obscene horsepower. That said, ive been buying Donghua chain in 10ft lengths on ebay and amazon for all my motorised toys, works great and doesnt really stretch. Great price too.

ok cool i have a stock 4 hp L head briggs. so we will be good, thanks brodie!!

 

[Baja_brandon96]

ok cool i have a stock 4 hp L head briggs. so we will be good, thanks brodie!!

4hp? You're definitely okay with #35. Ive been using #35 on my modded 212 predator doodlebug, if i had to guess makes about 8hp. Ive done countless launches, burnouts, and hill climbs and the chain is still fine. Will probably change it soon though anyway.