speed for the 50cc



Just started break in for my 50cc motor today, Im taking it easy but giving it a squirt now and then. will it get much quicker after beak in? because it seems pretty gutless, at around 18 to 20 mph it feels like Im ringing its neck. I was told the 50cc should comfortablely do around 25 to 30 mph. Or am I just asking too much of it duing break in? Im running the longer exhaust, the goldie colored one that goes right under the bike. thanks :D

hi, my 48's started out kinda sluggish, but around the 3rd tank they leveled out and run smooth. very little vibration. I was clocked on one at 33 mph. the other runs a consistant 28mph, with a 48 tooth sprocket.
hang in there...

I hate you lowlanders....I can't get that kind of performance at my altitude due to the 21% loss of HP that 7000 feet causes. BUMMER.
Hi Drew, there is a jet kit available for these engines that would probably help you with your altitude problems. As far as I know Mike Simpson is the only one that has them heres his site http://www.simpsonmotorbikes.com/ . Give him a call or e-mail him, they make a big diffrence in preformance...Kelly
thanks I will, It does seem to be getting a little better each day, smoother and less metalic noise etc. I had an 80cc on the bike and pulled it out due to the vibration, the 50 does seem to be a sweeter little motor. But i didnt give the 80 a real change I guess. Might drill a hole or two in the baffle, does that really make much of a difference?
Thanks for the tip about the jet kit. My lack of performance isn't about jetting. I fixed the rich mixture problem at my altitude by blending a small amount of methanol/nitromethane into my gasoline mixture so that the engine was running just shy of max lean.

Even properly mixtured, you will always lose power at altitude due to decreased air density. The same applies for my normally aspirated (non-turbo for those who who aren't into cars) gasoline powered vehicles...they are dogs at this altitude which is why 2 of my cars now are turbocharged but HP is derated after 10k altitude for both of these due to turbocharger speed limitations and risk of surge (blade stall) in a VNT turbo.

If I wasn't running methanol/nitro into my gas, I'd probably do a poor man's fix of the carb instead of spending $$$ for a new jet. The fix is to drill a small bleed air hole into the intake and adjust mixture from there.
I do about 26ish mph with the 80cc on a 44t sprocket. I want to drop down to a 32t sprocket, and I could imagine I would be doing around 35ish mph with that.
Tom said:
I do about 26ish mph with the 80cc on a 44t sprocket. I want to drop down to a 32t sprocket, and I could imagine I would be doing around 35ish mph with that.

all these 80cc with 44t sprockets should run about the same speed. (i'm guessing 30 mph, easy.) it kinda sounds like you might not be hitting your maximum rpm? maybe your throttle cable isn't pulling the slide far enough? my russian engine had this problem. after i adjusted the cable it went from 15mph to a whopping 21 mph.
just a thought
Strange about these 80's mine was doing 20-25 with 48 tooth during break in...
Of course this was on a schwinn Speedster, with 26" X 1-3/8" wheels, and I weigh in at 125, so there's less rolling resistance with this set up...
I am switching to the fifty tooth on this set up for the many hills we have around here, I like to not pedal assist when possible.
Maybe I'm strange, but I get a thrill and exhileration from feeling the torque of the engine pulling up hill. It's kinda like take-off in an airplane...