99cc Predator Specialized Rockhopper

Y

young grease monkey

New Member
After a year of this project collecting dust due to a lack of funds and proper tools to do it the way i want, it is back on the front burner. I have since acquired an AC/DC TIG welding setup, small HF metal lathe, various other metal working tools, lots of parts for the bike, and proper funds. So yesterday I mounted my go cart wheel hub on the engine mount to serve as the jackshaft bearing. Also got a set of forks from JNMotorbikes, a 55w bullet motorcycle headlight from Lowbrow Customs, and stainless steel tubing and butt weld elbows for the custom exhaust I will build. I had a front wheel built by my local bike shop using a Shimano XT m756 disc hub and sun ringle mtx 33 downhill rim with 14g double butted spokes. And, of course, pictures! Just follow the link to my photobucket album. http://s1244.photobucket.com/user/polyesterb/library/motorized bike?sort=3&page=1
 
YES it does look great,just wondering about the jack shaft mount though looks a little thin maybe brace it some................Curt
 
Thanks guys! Yes yes of course, I will brace it like crazy! I made that bearing plate when all I had was a 80 amp hf welder so it's 1/8 inch thick. I put that piece of tubing on there to brace up to. Also I designed the jackshaft so it would have relatively small torque on the mount. The belt and chain create opposing forces that partially cancel out, where if the bearing was in between the sprocket and pulley it would be taking a lot of force to keep the shaft in place. My design also allows the pulleys to be placed super close to the engine for the most compact settup possible.
 
I put some more pictures in the album, just use the same old link. Frame mounts are made of tubing I got from McMaster-Carr, similar ID as frame OD. About 6" lengths I split down the middle. I also got some hose clamps from McMaster, stainless steel ones that have bolts to get some serious clamping force on the tubes.

Also in the new pics is a mock up with new handlebars and stem, just finished installing the new threadless headset today. Had to turn down the steer tube on the lathe for the new race to fit, then slammed it home with pipe and sledge! It was too late when I realized I should have turned it down more, so I shook the whole work shed with hammer blows haha
 
Today I picked up 2 deep cycle sla batteries, 12v 5 ah each. They will give me 2 hours of high power lighting! Also got some toggle switches for the ignition and light with rubber boots, gotta make a box and mount for them. Next is final grinding on the engine mount before it gets sand blasted and painted or powder coated, will have to get a quote on powder then decide.
 
Finished the exhaust minus the muffler which i will work on later, just trying to get it rolling for now as I'm starting a new job and need transportation. Pics of the exhaust can be found in the link in the OP. It sounds really mean when i gave it some revs, a lot like a 4 stroke dirt bike but better in a way.

Anyway I also worked on the chain tensioner, using a really beefy 18t idler sproket with built in bearing from mcmaster and some 1/8x2" flat 6061. The flat stock will get clamped to both "legs" of rear triangle for ample support.

Got stock for the tank as well, I am "borrowing" Scotto's idea of using square aluminum tubing for the tank. I got a foot of 5x5 .125 wall from mcmaster for under $30, and some .125 wall tubing to make the tank straddle the top tube instead of just sit on top of it.

So do you guys have a suggestion for a carb? I'm going to relocate it anyway since the stock carb position sticks into my thigh, so might as well upgrade right? Plus i have extra elbows and tubing from building the exhaust. AGK is sold out of their 19mm. I need something the won't be very tall as i want to mount it behind the engine but inside the front triangle, and as you can imagine there are considerable constraints on such a design.
 
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