weed whacker question

dirtbikemike2435

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i have found a 25cc homelite... and so i am wondering if a 2" bmx peg is too large, what type of speed to expect. also i dont mind pedalling at first:cool:
 
From what I read, 2 inch is too big. Oh, and tire size doesn't matter. The tire is just a big roller between the drive and the ground.
 
From what I read, 2 inch is too big. Oh, and tire size doesn't matter. The tire is just a big roller between the drive and the ground.

Nonsense, he could use a 10" wheel if he wanted to. It would rob torque, but he could go fast eventually. A 2" bike peg is fine.

Out of curiosity, what model is your motor? I have a homelite SX-135 I just rebuilt.
 
i have found a 25cc homelite... and so i am wondering if a 2" bmx peg is too large, what type of speed to expect. also i dont mind pedalling at first:cool:
Using a 2" bmx peg as a drive roller.......

@ 7000 rpm's would get about 41 mph.

You would have to pedal up to about 30 mph before the engine would try to pull you.

Factor in wind resistance & your weight.... at this proposed speed, I doubt this engine would do much more than scream..... in agony.

A 1" drive roller would get you into the low to mid 20 mph range & allow for your engine to work within its limits.
 
Nonsense, he could use a 10" wheel if he wanted to. It would rob torque, but he could go fast eventually. A 2" bike peg is fine.

The surface speed of the roller needs to correspond to a reasonably achievable surface speed for the bike. If you "gear" the motor too high with too big a roller, you'll burn up the centrifugal clutch and never get all the motor's power to the tire where you can use it.

Weedwhacker motors typically make their maximum power at about 7000 rpm. The surface speed of a 2" roller at 7000 rpm is almost 42 miles per hour. One horsepower from a trimmer engine can't propel you that fast. The motor will bog down and the clutch will burn. The bike will never attain even its max torque speed, let alone the speed at which it makes its rated power.

The surface speed of a 1.25" roller at 7000 rpm is 26mph. That's a realistic top speed for a one-point-something horsepower motor on a smooth running bike with an average sized rider.

Chalo
 
Thanks alot guys, is their any other ideas i can make a drive roller out of because i have yet to see a 1.25 bike peg, i have a 1.5 bike peg, also i have heard of people using a socket? any ideas
 
I have seen knurled axle pegs about 1.25" in diameter, but they were the small kind with 3/8" nut threading in one end. The knurled part was welded on, so there is no reason to think they'd run particularly true, either.

What does your motor have to attach to?
 
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