motor arrived today



I was suprised how small it was and its the 80cc. Fit and finish is not the best but I wasnt expecting Japanese quality. I wonder why honda or suzuki or one of them dont jump on the band wagon and start making bicycle motors like these, sure they'd be twice the price but sweet as. Anyway its very cool, will change all the bolts to better quality high tensile, I'll use a good dirt bike twist throtle, and change the clutch lever to something better too. Pretty much all the periferals need upgrading. Unfortunatly my bike having 3 inch wide tyres the chain will never clear it. Going to buy an electra rat rod like in one of the pics posted on "my first 80cc" posting and fit the motor into that. Keep your knees in the breeze lads.
3 inch tires?!?! jeeze, my motorcycle doesnt even have that big tires.

Honda and Yamaha should make these motors, but I think there is an issue with liability and/or sales volume. How much money would they really make off something like this...
3 inch tires

You can get the chain to clear fat tires by removing the drive sprocket on the motor, flipping it around, and adding a washer or two to space it out away from the motor. Make sure to use red loctite when you tighten the drive sprocket back on. These two things will move your chain out just barely enough to clear the tire.
Now may need to clear the inside of the frame. Add an extra nut to the rear axle on the inside of the frame on the motor chain side to push the frame apart a little, and you should be ready to go. This is how I motorized my Nirve Switchblade Chopper and got to keep the original fat tire on the back.
The chains might be pretty close to the tire on each side, so make sure you adjust the wheel position with the bike straight up and down, not leaning to the side on it's kickstand. If the wheel is rubbing on one of the chains, you can just point it left or right a little. It's not going to be noticeable if the tire isn't perfectly aligned and it dog-tracks just a little. If you want to get super cool, you could "dish" the rim by tightening the spokes on just one side or the other, which would offset the wheel to the side of the tightened spokes while keeping the wheel perfectly in line with the frame. I wouldn't bother with dishing it myself, but it is an option.
If you're still having a hard time getting both chains to clear the wheel, add a washer or two to the crank on the inside of the pedal-drive sprocket. This will push the pedal-drive chain out just a bit and it will give you more room to adjust the tire away from the motor-drive chain if you need to.
3 inch tires

Oh yeah, and I also had to add washers to to the motor-drive sprocket cover. This was to shim the cover out just a little to adjust for the sprocket sticking out further. Always check clearance and see if anything is rubbing when you change stuff like this. Have a dremel tool or file handy and be ready to grind a little bit if you need more room. Just be careful where & how much you grind. I had to grind 1/4 of one of the washers away because it was hitting the motor chain. When I put the cover on, I have to make sure that one washer goes in the top right spot and that it has the flat spot towards the chain (not a difficult thing to do).
Great info in the last two posts Blaze. Could you post pics? This would be good in the How To area for easy access. Thanks...Kelly
yes that is great info, but to clear a 3'' tyre both the drive and the rear sproket will have to come out heaps, would this method suffice? my pedal chain is cool as its spaced out from the factory. the bike is an electra model with the 3'' fattio tyres. The wheels are only 24'' and the big tyre side walls make it a 26'', if I change the tyre for a thinner one on the same wheel I lose side wall and it becomes a 24'' and the kick stand is too long and the pedals just barely clear the road. was going to buy a 26'' wheel and tyre and 3speed hub gears and coaster brake but its really expensive.
For the sprocket that is bolted onto the spokes of the back wheel, you want to add an extra rubber ring between the sprocket and the spokes. If you have lots of space for your pedal chain, you can point the tire to the right just a little to bring the tire closer to the pedal chain and give the motor chain more room. If you just move it a little. it won't be very noticeable. If you have coaster brakes, then you have to worry about the coaster brake torque arm rubbing on the sprocket that's bolted to the spokes. That will require welding a nut in between the torque arm and the brake pad locking assembly to move the torque arm out far enough to clear the sprocket. Pain in the ass, but it works. The picture doesn't show the parts or anything, but you can see that I am running a pretty wide tire. I hope you get it to work for your tire.
No problem. Since the weld recently broke on my coaster brake arm (it lasted over a year, so that's not bad), I am engineering a new method for spacing out the coaster brake arm enough to clear a sprocket with an extra rubber ring under it. This one will involve fabricating a new arm with spacers welded to the arm, but no welding on the brake stop (the little round peice inside the hub that attaches to the arm). This will allow for switching out parts and replacing hub internals without the need to get the new brake stop welded to the arm. This will also save thin little bearing cover that gets destroyed during the welding process. I'm sure part of my problem was beach sand in the hub causing it to lock up and stress the assembly. The last step will be to grind out the hole in the center of the motor drive sprocket to be large enough for the bearing cover to fit through. This should be done for every sprocket that ever gets installed on any bike. Without the hole large enough for the bearing cover to fit through, you will have to remove the sprocket every time you disassemble the hub internals.
coaster brake mod

I posted the coaster brake mod in the DIY forum, and I'm going to add the part about getting your chain to clear the tire.