52cc Stage 2 CAG CVT powered X-Games Motobike
- Thread starter 16v4nrbrgr
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- motorized bicycle
Yeah, it is kinda more like a moped or scooter because I can't figure out how to have 15" wide crank arm spacing without digging in, lol. In Europe you guys get all the good small displacement motorcycles, and I can't afford the headache of an Aprilia or Derbi 50 unfortunately. An upside to this bike is the individual parts are all very affordable so I should be able to afford staying up on maintenance. The stage 2 engine was only $100! 
Set up a muffler bracket, might revise it so it exits straighter
Used a split collar drilled and tapped to put a fat disc on the rear
Riveted and ziptied a plastic rear guard on the swingarm
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There's that.
Here you can kinda see the aluminum heat shields I made to keep the number boards from melting.
Had to shorten the chain by about 9 links, I'm going to see if I can use the Connex link to make it easy to stick in the car with the wheels and chain off.
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I just read this entire thread front to back.
Really reminds me of a street version of one of these:
Very nice build, very nice!
Really reminds me of a street version of one of these:
Very nice build, very nice!
Thanks for the kind words guys. I think the bike should be a great deal of fun, its gonna be about 60lbs dry, and I weigh about 145 with my gear, so if it will take off well from a stop, it should be aok as long as I remember to upshift so as not to spin the chain to the rpm it might bounce. I'm glad that other members have been attempting their own shifter bikes so I have some idea whether the gearing will be appropriate and if the derailleur can take it.
Last night I set up the carburetor and the throttle cable, quite a pain since the cable sheath needed shortening by 1/2". I also hooked up and adjusted the derailleur and installed the chain as can be seen in the pics. Today I'm going to hook up electrics, see about making a kickstand bracket for the scooter kickstand I bought for it, and work on the fairings.
I'm tempted to fill it up with gas and go for a warmup and breakin run, but once they're full of gas they aren't so friendly to work on inside so I think I'll chill and finish everything I can.
Last night I set up the carburetor and the throttle cable, quite a pain since the cable sheath needed shortening by 1/2". I also hooked up and adjusted the derailleur and installed the chain as can be seen in the pics. Today I'm going to hook up electrics, see about making a kickstand bracket for the scooter kickstand I bought for it, and work on the fairings.
I'm tempted to fill it up with gas and go for a warmup and breakin run, but once they're full of gas they aren't so friendly to work on inside so I think I'll chill and finish everything I can.
The bicycle turn signal thing already broke a couple wires trying to put batts in it, lol whatever.
Ain't gonna be no slipping off the back of this bike
Now its ready for a tank of gas, unless I decide to wait for the bodywork and a speedometer...
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Opted for a tank of gas, and she runs! I took her out for one spin and it wouldn't stay in 1st, tightened the cable and adjusted the derailleur and its good to go. Goes very fast even though its got 0 hours on it lol, already had a bunch of old people pissed off, boo hoo.
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That is one sick ride dude. Fabulishious!
Only problem I see is convincing the cops it's actually a bicycle, pedals or no!
Looks very cool!
Only problem I see is convincing the cops it's actually a bicycle, pedals or no!
Looks very cool!
Thanks dude! I'd uh, point to the derailleur, lol. I think it might just be a toy to bring to the racetrack, I don't really see a use for this type of thing around town, lol!
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What a stunning build! I'm amazed at the transformation that you've wrought, - much better than any pocket bike IMHO.
Yeah, I love pocket bikes, especially the super pocket bikes with dirt bike four strokes, but they are classified as illegal since they fit into a category for off road use only. I think the original law was passed to get the small fast European pocket bikes with 10+ hp off the street since they are death traps used that way, no visibility and all the surprise. This is still kinda like a motorized stand up scooter because I could technically "surf" on it, lol.
Scooters don't need reggy here, and with the gearing as tall as it is, it likes a push off from a start to get going. It will get better as it breaks in and I get a better plug, might take a couple weights out of the variator to make it stay in low longer before shifting up.
If I can find a gearing solution, either welding an 11t onto the motor sprocket, or adding a 41t to the cluster and dropping the 11t 9th, then it will do all the hills around here in between towns, so I'll have to get a plate for it. Nopeds are common around the SF Bay fortunately, since there are so many mopeds and scooters from over the years, and road congestion is the biggest concern.
Scooters don't need reggy here, and with the gearing as tall as it is, it likes a push off from a start to get going. It will get better as it breaks in and I get a better plug, might take a couple weights out of the variator to make it stay in low longer before shifting up.
If I can find a gearing solution, either welding an 11t onto the motor sprocket, or adding a 41t to the cluster and dropping the 11t 9th, then it will do all the hills around here in between towns, so I'll have to get a plate for it. Nopeds are common around the SF Bay fortunately, since there are so many mopeds and scooters from over the years, and road congestion is the biggest concern.
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Well I gotta do some improvements before another ride. The clutch could use lightening because I think having it pick up at 6000is limiting the bike, when it gets hot it slips and picks up lower and slips, generating too much heat. It kicked out a lot of gear oil since it got hot and thin and it was burning on the pipe, so I need to control the temps, possibly use grease in the gear reduction to prevent leakage. The copper fitting at the pipe union needs silicone and the whole pipe wrapped to keep as much expansion chamber heat away from the gear reduction to keep it all happy. It doesn't get really too hot from the proximity of the pipe, the plastic filler plug and breather are fine, but its worth the effort since I have the supplies left over.
I should also pull some weights out of the CVT and see if I can keep it in low longer before upshifting in the powerband, which will make it more beneficial. A bigger rear cog may be on order if those mods don't help the low gear performance. The mtbtools 41t may work to shift the stack over and provide a takeoff gear, otherwise I can possibly weld a 11t cog onto another motor sprocket, but that's a last resort since the current 14t is a good diameter for the 1/2" pitch 9 speed chain, and distributes the torque over more teeth. Supposedly chain stretch and failure is an issue with strong cyclists, and I want to avoid that at all costs, as well as gearing so low that it over torques the drivetrain. For this bike I will be satisfied with mild hill performance and high speed flat ground performance since its going to be a race bike eventually, or at least just a toy. When its cool and the clutch is hooking up right, the performance is great, and raising the stall speed helped on the BMX so I'm goint to try it again. This time I'm going to be conservative with the lightening at first because I only want to raise the stall to about 7000 rpm, and I don't know how these 3-shoe clutch arms and springs respond to lightening yet.
I'm thinking I might work on the streetbike fairings this weekend if there's time.
Thanks for everyone here on the forum and local who said they like the project. I saw some nice kids who expressed interest the other day but I was drowned out in noise and trying to adjust the idle, lol Dang thing idles at 3000 rpms, I should check for a vacuum leak as well, lol.
I should also pull some weights out of the CVT and see if I can keep it in low longer before upshifting in the powerband, which will make it more beneficial. A bigger rear cog may be on order if those mods don't help the low gear performance. The mtbtools 41t may work to shift the stack over and provide a takeoff gear, otherwise I can possibly weld a 11t cog onto another motor sprocket, but that's a last resort since the current 14t is a good diameter for the 1/2" pitch 9 speed chain, and distributes the torque over more teeth. Supposedly chain stretch and failure is an issue with strong cyclists, and I want to avoid that at all costs, as well as gearing so low that it over torques the drivetrain. For this bike I will be satisfied with mild hill performance and high speed flat ground performance since its going to be a race bike eventually, or at least just a toy. When its cool and the clutch is hooking up right, the performance is great, and raising the stall speed helped on the BMX so I'm goint to try it again. This time I'm going to be conservative with the lightening at first because I only want to raise the stall to about 7000 rpm, and I don't know how these 3-shoe clutch arms and springs respond to lightening yet.
I'm thinking I might work on the streetbike fairings this weekend if there's time.
Thanks for everyone here on the forum and local who said they like the project. I saw some nice kids who expressed interest the other day but I was drowned out in noise and trying to adjust the idle, lol Dang thing idles at 3000 rpms, I should check for a vacuum leak as well, lol.
I'm gonna stop kidding myself, and bought this 41 tooth cog for the cassette off Ebay from mtbtools, I heard they kinda suck, but I think if I bolt it into the PG-990 hub it should work better than it has for people not mounting them correctly and bending them, it looks like its tougher than the 34t bottom gear I have currently, lol! I have to drop a top gear to accommodate this, no problem, they're useless.
I'm going to try drilling some 1/8" holes in the clutch arms to raise the stall a bit so shifting is easier because it engages so quickly off idle that its easy to give it too much stick when shifting and it sounds loud lol! It should get into powerband better this way and hook up better when hot.
I need to get an impact gun or bring the trans to work and buzz the varietor nut off, it doesn't look like there's provision to counterhold the pullies, maybe by hand gorilla style...
A strap wrench works good to hold the variator pully while wrenching on it.
http://www.harborfreight.com/2-piece-rubber-strap-wrench-set-94119.html
http://www.harborfreight.com/2-piece-rubber-strap-wrench-set-94119.html