Schwinn Kokomo won’t work.

Man I’m looking at this Kokomo seriously right now but I’m not understanding how you put the sprocket adapter on there... you said you ground down the adapter but wouldn’t that make it a looser fit? And if the hub has a taper to it I don’t see how you’d be able to keep that sprocket adapter trued up under torque? Looking to buy one now but looking for more clarity... looks great though!
 
Sounds like a clearance fit bud.
It was when I got it, read where I took .005" off one cap. I also mentioned that the shaft has a slight taper, but the taper doesn't begin until the outer part of the hub. The hub adapter is make good contact for about 3/4 of its width, then the taper begins. If the 3/16" pin doesn't hold it I'll try something else.
 
Peg > hole = interference
Hole > peg = clearance

You can change an interference to a clearance buy removing material but you can't go the other way without adding material. I'd be impressed if such a small pin could really with stand any amount of torque before shearing off being that close to the center of rotation
 
Man I’m looking at this Kokomo seriously right now but I’m not understanding how you put the sprocket adapter on there... you said you ground down the adapter but wouldn’t that make it a looser fit? And if the hub has a taper to it I don’t see how you’d be able to keep that sprocket adapter trued up under torque? Looking to buy one now but looking for more clarity... looks great though!

The hub adapter is 2 piece and the way it goes together there is a split line where the 2 halves meet. I just took .005" off the mating surface of one half by rubbing it on a piece of emery or sandpaper placed on a flat surface. Doesn't take long or very many strokes. If .005" is not enough I can take more off. The taper in the shaft is an issue, but the taper begins on the outer portion so most of the adapter bore is making contact.

The center hole in the sprocket was 0.040" too small to fit over the wheel hub. I used a grinder to carefully enlarge the hole in the steel sprocket until it just fit over the snout of the wheel hub. I had to pull it in the last little bit with the 3 mounting bolts (taper working for me here) so I have a 0.0165" thick steel sprocket fitted tightly on the wheel hub and bolted to the hub adapter with three 10mm bolts. The sprocket is tight to the hub where the torque is applied and there is 3/16" pin preventing the hub adapter from slipping on the wheel hub. There may be other and better ways to do this but without a machine shop handy this is my way of mounting a sprocket on a Kokomo. As soon as the engine arrives I'll know how reliable it is.

When I ordered the Kokomo I also ordered a mag wheel sprocket thinking it would bolt right on LOL. Looks like it is made to mount in place of a disc brake flange but the Kokomo has none of that so I was back to the drawing board.
 

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Peg > hole = interference
Hole > peg = clearance

You can change an interference to a clearance buy removing material but you can't go the other way without adding material. I'd be impressed if such a small pin could really with stand any amount of torque before shearing off being that close to the center of rotation
Lots of people using these adapters without a pin with no slippage, the pin is only a little insurance. The pin itself is interference in the adapter because I used a drill bit a couple thousands smaller than the pin and drove the pin in. The other hole in the wheel hub is size to size, neither clearance or interference. If a 3/16" pin shears I'll go to 1/4".
 
I had an engine kit ordered from China but they were jerking me around so I canceled and ordered a kit from Walmart and it arrived today. It is a Zimtown which I never heard of but looks pretty good. It has 8mm studs, Allen screws in the covers, a 4-bolt chain tensioner and a muffler support. It even came with a manual. I did a quick try fit on the bike and the front frame is too wide for the studs but it fits using the wide bracket and u-bolt without any modifications. It is a one piece cylinder/head style engine, first time for one of those. That is not what was pictured in the Walmart ad but I may be better off because it is a more compact design. Shouldn't take too long to get it going, the only thing I'm missing is an offset intake. The ad said it has a 40mm intake but I need to measure before I order the intake.
 

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I started out with that exact same kit back in February, same manual even! The only difference is mine was a 32mm intake and had 6mm mounting studs. It was an awfully weak motor but I suspect much of that was due to me not taking the time to clean out the ports and transfers of casting schmoo. Looks like it fits quite nicely on that Schwinn.
 
Did you buy the kit from Walmart and was the jug one piece? It turns out this kit has 32mm intake also but it does have 8mm mounting studs.
The small appearance of the cylinder had me wondering if they sold me a 49cc kit so I pulled the cylinder off and the bore measures 47cc so it is 66cc.. I was impressed how clean and well lubricated it was inside. Much better than some kits I've seen and the cylinder is powder coated. I don't know much about the porting of this type of 2 cycle engine but it doesn't look too bad to me.
 

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I used a 1/4" electric die grinder to shape the front motor mount to fit the frame. That allowed the motor to sit low enough to mount the carb with the intake from the kit. I dimpled the down tube for front mounting stud clearance. I also had to grind some on the rear motor mount and notch the fender for chain clearance. The 36 tooth sprocket requires more pedalling to get going but it cruises nice. On the first ride when I was getting close to 30 mph the front end started shaking like crazy. I suspected it was a wheel balance issue and the heavy spot was in the area of the reflector. I removed the reflector and that fixed it, very smooth ride at any speed now. That is how I motorized a Kokomo. Now I have to find another cool bike to work on.
 

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No, I grabbed mine from ebay. It was this listing here but I paid wayyyy less (thanks Trump for your damn trade war)
https://www.ebay.com/itm/Full-Set-8...-Petrol-Gas-Motor-Engine-Kit-Set/401314978701

Seeing the pictures you posted of the inside, I think mine was a different "1 piece jug/head" build as I want to say mine didn't have the open transfers like that. With doing port work, if your not sure just simply clean up any sharp edges or anything that might interrupt the smooth passage of air. Try not to change the size or shape of anything until you know for sure what your going for.
 
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