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Old 07-05-2010, 06:37 PM
KCvale KCvale is offline
Motorized Bicycle Elite Member
Join Date: Feb 2010
Location: Phoenix,AZ
Posts: 3,552
Default KC's GT1 build with tips.

Other than a couple of gripes like the drum brake being virtually useless, the dual rear wheel brake lever uses a fixed position and not a teeter-totter for varied force, and everything already mounted on the handlebars when it all has to come back off....

I love this bike!

48cc Black Grubee Skyhawk GT-2B motor, port matched.
Upgraded wiring with Keylock ignition.
Upgraded foam racing grips and automotive gas line.
No chain tensioner.
Everything else came on the bike.


Motor and Chain:
This bike is a breeze to chain match so you don't need a tensioner.
1. Set the motor in place leaning slightly forward and tweak down the seat post back clamp.

2. Your back wheel should come sitting true and your pedal chain firm.
Loosen the wheel nuts and brake nuts and then back off each "holding clamp" nut one full turn so the wheel can move forward to loosen the pedal chain.

3. Remove the motor gear cover and spark plug, then thread your chain through using the plug wrench on the gear nut until the top side of the chain sits on the top of the rear sprocket.

4. Wrap the bottom portion of the chain up and around the rear sprocket with as little slack as possible so it meets the other end on the sprocket.
You will find that the chain is 1/2 a link off.
Break your chain back 1 link and then put on a 1/2 link.
Put the chain back on with the master link and it should look like this.

Note that those link parts retaining sides face out, and the solid side of the master link clip points forward in the direction of travel.

5. Now loosen up the seat post motor mount nuts and slip a shim between the motor and mounting block (not between the block and frame) until the drive chain is very firm, you will need ~3mm of shim.
I just used what I have around, a dust cover plate for a PC case slot folded in half with some cardboard shims in the middle.

Once the the drive chain is firm tighten down both front and back motor mounts.
You can take the new slack back out by tightening the rear wheel "holding clamp" nuts equal distances until the chains firm up.

You want the motor chain a little tighter than the pedal chain.
After you put about 20 miles on it tighten them again until the drive chain is perfect, if there is to be slack after initial seating you want it on the seldom used pedal side, just don't get the drive chain too tight or you will wear the motor bearings. Besides, the rear hub mounted sprocket already comes attached in perfect alignment, you get chain jump with a little slack.

I will do the Handlebar Controls in another post, it has pics too ;-}
KC's Krusiers Builds
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