Engine speed

[Eddie Medley]

I have 80cc engine that tops 18 mph at best with 38 tooth sprocket, speed carb.
My old 80cc engine top 27 with 44 tooth sprocket with stock carb
I had 49cc with 38 tooth sprocket speed can that went 19 mph 20 at best

The engine now is sputtering a bit
How can I fix this

 

[crassius]

I'd first try a larger sprocket to see if problem is motor or sprocket.

 

[Eddie Medley]

I'd first try a larger sprocket to see if problem is motor or sprocket.

But wouldn't the smaller sprocket have higher top speed but lower torq then higher sprocket

 

[Street Ryderz]

But wouldn't the smaller sprocket have higher top speed but lower torq then higher sprocket

Yes but if your engine is not making enough torque to turn the smaller one you wont get the expected speed! What Crassius is suggesting is if you put the stock 44t gear on and it still doesn't get higher rpm's than it's the engine not the gear! Your engine should be able to turn a 38t gear with out much problem if all is good!

 

[gary55]

We are looking at a s**t load of variables here. Put the stock 44 t. sprocket on and see how it does. then trouble shoot from there if needed.

 

[Eddie Medley]

We are looking at a sh*t load of variables here. Put the stock 44 t. sprocket on and see how it does. then trouble shoot from there if needed.

Is there anything else I can try I don't feel like spending an hour switching sprockets6

 

[Eddie Medley]

We are looking at a sh*t load of variables here. Put the stock 44 t. sprocket on and see how it does. then trouble shoot from there if needed.

I did do a engine rebuild just stock only different is crank casing

 

[Eddie Medley]

I have 80cc engine that tops 18 mph at best with 38 tooth sprocket, speed carb.
My old 80cc engine top 27 with 44 tooth sprocket with stock carb
I had 49cc with 38 tooth sprocket speed can that went 19 mph 20 at best

The engine now is sputtering a bit
How can I fix this

I did take out some of baffle in the exhaust and have the racing carb

 

[Eddie Medley]

I did take out some of baffle in the exhaust and have the racing carb

I also have boost bottle

 

[crassius]

the two rules are:

don't get lazy
don't get in a hurry

most kits came with 41T sprockets till they found this was a problem for riders over 200 pounds or so and went to 44T sprockets

why not switch wheel & chain between the two bikes?