and the build begins

[motorstumpy]

So I picked up the bike today!

One picture shows is as it came from the LBS and the other (lowered seat post and flipped bars) shows the approximate geometry I will be using.

I think its gonna rip! Still a bit concerned about rear sprocket clearancebut iIhave a few ideas on how to fix if Irun into them.

I am going to paint the engine. But am on the fence with a color scheme. I am thinking white tank, clutch and magneto cover, black engine block and cylinder and a red cylinder head. But I can't decide if maybe all white with a red head or all white with a red cylinder and head for the engine. Thoughts?!?!?

 

[16v4nrbrgr]

For the drive sprocket, you can weld a 18t to the fixed gear side of the flip-flop hub to keep it from unscrewing, and bolt a 9 hole sprocket to it using the washer plates supplied in the kits.

I'd paint the engine with a flat black engine enamel sparingly, light colors, gloss, and thick paint will all inhibit the cooling of the engine.

 

[motorstumpy]

For the drive sprocket, you can weld a 18t to the fixed gear side of the flip-flop hub to keep it from unscrewing, and bolt a 9 hole sprocket to it using the washer plates supplied in the kits.

I'd paint the engine with a flat black engine enamel sparingly, light colors, gloss, and thick paint will all inhibit the cooling of the engine.

Yes I have read that the track gear will unscrew but with a lock ring on it I have a hard time seeing how that will happen. So yes the threading on the track cog is in the right direction to unscrew when on the left side go the bike ("wrong side") and force is applied on the top of the gear pulling forward, Rotating the cog counter clockwise... But there is a lock ring that is threaded in the opposite direction and if it is on hard against the track gear there is just no room for the gear to move into.

That being said I think drilling and installing set screws into the cog so that they fit into slots I cut in the hub should suffice. Or maybe JB weld.

Realistically I don't think I am asking much more of from the drive train then a strong, experienced cyclist would. I used to work with a guy who pushes 35 on his single speed fix gear... Yeah he's a beast.

As paints goes I am going to start with the covers I think. But idk. There is a bunch of fab work that has to happen before I can start painting so I got time.

 

[KCvale]

That left fixie sprocket is a moot point unless you planned to mount a screw on much larger sprocket as that little 18T won't cut it for a motor drive sprocket unless you want to pedal up to 25MPH just to start it so you can ride 50 MPH when you get going.

I'd just unscrew the fixie off and use the kits spoke mounted sprocket.

For engine paint I find the 2-tone look nice and there are a lot of colors of high temp motor spray paint though not likely white.

White for all your mounting parts would be a nice touch.

Personally I like gloss black for the head and covers but regardless I recommend using PlastiKote engine enamel, it's all I use for anything on a bike even mounting parts as the stuff is gas resistant and tuff.

Just some tips and it looks like you are on your way to a really fine ride.

 

[Sidewinder Jerry]

You could also get a Staton hub it has right hand treads on the right and left hand treads on the left side of the hub. He also sells an adaptor for the gear.

 

[motorstumpy]

Got the motor mounted today and all is well. Fits better then I thought it would. Gotta take maybe and 1/8 of the last 2"post the inside of the cranks to clear the motor.

Tomorrow after work I will drill and mount the rear sproket
..at least that's the plan.

I am going to use big ole hose clamps to mount the tank. I think it is a good alternative to the leaky studs.

would post pics but my phone is not liking it for what ever reason.

 

[16v4nrbrgr]

When you bolt the big kit sprocket to the 18t the torque is enough to taco the lockring holding the 18t its bolted to from unscrewing. What I did on my BMX was put a lockring on there and weld it about 1/4 at the very end of the threads in three spots, small tack welds aren't enough. If you ever decide to remove the 18t, you can grind the welds off and remove the lockring, and clean up the end thread with a small file.

It's a cheap way to use your existing hub with a couple welds from a shop that would take 5 minutes and pocket change. Bottom bracket lockrings for crank axles are the same size and thread pitch as rear sprockets, in case you're having trouble finding a steel one.

 

[motorstumpy]

got my two sprockets welded together the other day by norm at venice motorbikes. the rear assembly is now in painted and mocked up on the hub.

As you can not weld the steel cog to the aluminum hub I am going to go with jb weld and a boat load of torque. If it strips out I'll buy another and have a hub adapter made or switch it out with an old 29er mtb rim I have and use the disc brake mount to mount the rear sprocket. Guess I coulld force a rag joint on it too but its a 32 spoke wheel so it will be interesting. Did it on my last bike and it worked ok.

some would argue that i should just go straight to the mtb wheel... But its not "pretty" like the stock one and Ii havent pulled it from storage to see if it will really fit. I know the bearings in it are kinda rough too and should be replaced.

i have high hopes for the lock ring and jb weld. I have seen WAY more sketchy stuff survive on other ppls bikes... And if if breaks, it breaks. But if i dont try it I know I will always be left wondering!

More pictures to come this weekend. The future wife is away and so I will play!

 

[motorstumpy]

And there she is! Now we just need gas.

 

[KCvale]

Nice Job ;-}

 

[motorstumpy]

Rode it to and from work today... Ran like a top. Took it only to 3/4 throttle... Did high 20s to mid 30s Im sure. The frame is super stable at speed and is way more comfortable then I thought it would be.

The rear sprocket assembly is holding up great no hairline cracks to play no nothing.

So far very happy.

 

[KCvale]

Cool, nothing like building something yourself and being surprised with with how well it functions, again nice job and your white handlebar end caps gave me the idea to see how yellow end caps on my current yellow and black build ;-}

 

[paul]

nice job and awesome looking motorized bicycle build, those tires look small, what size are they and how is the ride with them? the roads here are beyond bad and big 2.3 plus tires are a must or the roads will will beat the heck out of you. most mountain bike paths are smoother then our roads lol

 

[motorstumpy]

Ties are small. 700c X 28... And very high pressure running at 80psi.ride is good in spite of this. LA is not known for having well maintained roads but I a careful to go around the gnarly bits or at least slow down.

The end caps are actually Oury grips. Very comfy and good looking too. I would def recommend to anyone!