Is it possible? - Motorized Bicycle

mybike1 · #1 01-30-2013, 10:24 PM

I have a 3 year old Grubee skyhawk 66cc motor and am having problems
getting my chain away from my rear tire. I can make the adjustments
I need to move my rear sprocket out and away, but then it likes to throw the chain.... so, does anyone know if I can possibly put a small spacer behind the from drive sprocket on the motor? I think 1/8" or maybe even 1/16" would help out.

jji7skyline · #2 01-30-2013, 10:28 PM

My chain isn't perfectly aligned, but a tight chain and a well adjusted chain tensioner keeps it in place. I'd recommend that. Also, tightening your chain sometimes helps. (I know it doesn't work out logically, but it works on my bike :P)

mybike1 · #3 01-30-2013, 10:38 PM

yeah, that doesn't seem to be as forgiving on mine.

maniac57 · #4 01-30-2013, 11:48 PM

Maybe try removing the rear sprocket and turning it over so the cupped side faces out?

mybike1 · #5 01-31-2013, 01:20 AM

No, I dont have that type of sprocket...and adjustability isn't an issue in the rear... it's finding a way to move the front sprocket out... I kinda thought this might have been a common problem and was hoping for a quick answer. I guess I'll pick up some wrenches and figure it out tomorrow.

Venice Motor Bikes · #6 01-31-2013, 09:00 AM

You cant move the front sprocket out because the shaft is tappered... If you really can't do anything with the rear sprocket?, I would suggest 'off setting' the whole engine, (like custom builders do with Harley engines).

Bikeguy Joe · #7 01-31-2013, 09:03 AM

Or go with a thinner rear tire so it doesn't rub. A straight chain run is more important that a fat tire.

SavageBlunts904 · #8 02-01-2013, 09:23 PM

try using a 26"x1.75" tire. their great.

**2door** · #9 02-01-2013, 09:32 PM

If the issue is only 1/8" I'd offset the rear sprocket outboard. 1/8" shouldn't be enough to derail the chain unless your tensioner is not aligned and it's pulling the chain off to one side. Are you certain the engine is centered in the frame and not cocked off center?

Take a good look from the rear of the bike forward and check to see you have a straight line between the sprockets and the tensioner. Better yet, lay a straight edge along the sprockets. I like to use a length of 1/4" aluminum channel. I clamp it to the rear sprocket next to the teeth then check to see where/how it lays at the engine drive sprocket.

Ideally it should touch at exactly the same place on both sprockets. Your straight edge must be flat against one or the other sprocket, touching it on both sides and it should mate exactly with the other sprocket.

Tom