Help please!

[Gh0stRider]

You can't beat BMP's kit, on special now for $129. It used to sell at $159.00......

......On the BMP, replacing roller and bearings can be done in less than two minutes. And you WILL be replacing bearings.

Well, it's $149 if you want the 1.25" roller, plus throttle, plus kill switch. Still less than 200 bucks with all the trimmings.

I got a scratch n' dent from them for $119 (the powder coating process got screwed up leaving blemishes), but it looks like they sold them all already. Opted for the 1.25" roller but bought a 1" roller to mess with. Got the trigger throttle, the kill switch - now I just need to get a suitable engine running.

I have a Chinese TL clone that needs a carburetor. That engine has electric start, so the starter motor can be run as a generator for lighting.

I was also considering a mini-moto engine, as they are less than $100 brand new. They feature crankcase induction, reed valves, and sport a decent copy of a dellorto carburetor. Problem with the minimoto idea is that those engines are tuned for high revving power, and will have very little torque. In the little bikes they were meant for, the clutch doesn't fully engage until you hit about 20 mph but once revving, the engine will launch you to 35-40 mph depending on your gearing. All this with 49cc's and no gears. I'd also have to rig an exhaust for it.

I'm busy with other projects at the moment, but hope to get the BMP kit on a bike soon.


5-7, how long do the bearings last before they eat themselves? Do the one-ways in the 1.25" roller last?

 

[5-7HEAVEN]

The bearings lasted less than 1000 miles and one year for me. Then, it'll depend on weather conditions. I rode my MB in the rain and thru puddles. Maybe if I added grease it would've lasted longer.

The outboard bearing ALWAYS failed, not the one closest to the engine.

With the BMP, you don't even have to remove the engine. Raise BMP housing past the struts, remove circlip and outer collar, tap out bearing, install new bearing, collar and circlip. Lower housing, adjust roller and you're done!

Two one-way bearings failed on me in less than a month. I played around with one and the bearing started working.

 

[Gh0stRider]

When the one ways went, did they start to slip or did they lock up and lose the freewheeling? Sorry for all the questions!

Maybe I'd be better off with the 1" roller and minimoto engine. At 9K RPM, I'll be doing about 25mph (accounting for a little slippage loss) and 7,500 RPM will have me cruising around 20 mph - which is plenty enough for me on a bicycle. I'll miss the 30+ mph of the HT engine, but I like the fact that I could repair a rear tire on the side of the road without having to deal with two chains.

 

[5-7HEAVEN]

They locked up and lost the freewheeling.

FWIW, you want to find the speed you'll most likely be spending most of your time in, probably your cruising speed. THEN, you'll want to have your engine's "sweet spot" there. It might not be the engine's power spot, but one that you feel that the engine and your comfort level for exhaust noise and engine whine is at.

You'll feel that man and machine can run for quite a while, maybe all day.

That's why it's so much fun for me to experiment with different size rollers.

 

[Gh0stRider]

Thanks for the insight. The whole friction drive concept is a mystery to me. I'm used to the generic chinese frame mount 2 strokes and have considerable experience in the care and feeding of them. My main reason for toying with the friction drives are noise concerns, the simplicity and easy tire repair are icing on the cake.

I think I will try both engines. I ordered a minimoto engine the other day, but I need to fashion an exhaust for it. I have a stock exhaust from an old bike, but it is a tuned pipe with minimal sound control. I think I can mount a "can style" muffler from a Mitsu TL on the minimoto. Not great for performance, but should be more quiet than a HT. Hopefully, the can muffler with breathe well enough for me to get 9,000 RPM's on a flat surface with the 1" roller. But you're right, I'll need to experiment to find a good "comfort zone" balance of engine revs, noise and speed. Thanks again for all the info 5-7!!!!

 

[Gh0stRider]

And maybe someday, a 4 stroke for the ultimate in putt putt quiet cruising. Just don't want to throw that kind of money at a bike right now.

 

[5-7HEAVEN]

Thanks for the insight. The whole friction drive concept is a mystery to me. I'm used to the generic chinese frame mount 2 strokes and have considerable experience in the care and feeding of them. My main reason for toying with the friction drives are noise concerns, the simplicity and easy tire repair are icing on the cake.

I think I will try both engines. I ordered a minimoto engine the other day, but I need to fashion an exhaust for it. I have a stock exhaust from an old bike, but it is a tuned pipe with minimal sound control. I think I can mount a "can style" muffler from a Mitsu TL on the minimoto. Not great for performance, but should be more quiet than a HT. Hopefully, the can muffler with breathe well enough for me to get 9,000 RPM's on a flat surface with the 1" roller. But you're right, I'll need to experiment to find a good "comfort zone" balance of engine revs, noise and speed. Thanks again for all the info 5-7!!!!

The best exhaust I've used on friction drive is the ADA S1 pipe from davesmotors.com. I've used the same pipe on pocketbike engine, Mitsubishi TLE 43cc and GP460 engines with great success. Power is improved, as well as rpm increase and significant loss in exhaust noise on every engine. I've even run the pipe without the muffler, and it's quiet enough to blend into traffic. You'll have to cut off and relocate the mounting bracket, tho.

 

[Gh0stRider]

I've got access to welders, but bending pipe will be the biggest issue with me and a custom exhaust. An expansion chamber "stinger" exhaust *may* attract the attention of local law enforcement though. lol

 

[5-7HEAVEN]

I just installed a Tanaka 47R engine onto my 1976 Huffy sportsbike. I'm using my BMP friction drive with 1.25" one-way bearing roller.

Those same rollers that had lost their freewheeling are now working properly.

Go figure!

Never had problems with the local fuzz before, although a sheriff pulled me over once to check out my bike. He was all smiles from the moment I stopped until he pulled way. I was running twin Mitsubishi engines, and both had shiny chrome exhausts.

 

[moondog]

I just installed a Tanaka 47R engine onto my 1976 Huffy sportsbike. I'm using my BMP friction drive with 1.25" one-way bearing roller.

Those same rollers that had lost their freewheeling are now working properly.

Go figure!

Never had problems with the local fuzz before, although a sheriff pulled me over once to check out my bike. He was all smiles from the moment I stopped until he pulled way. I was running twin Mitsubishi engines, and both had shiny chrome exhausts.

Yeah, old Huffy ! They almost built a motorized bicycle in the 70's like Roadmaster bicycle did ! ( 50 state street legal to this day, thank you, thank you Roadmaster )

Roadmaster went with friction drive for their motorized bicycle. i wonder what the Huffy might have been like ! (maybe yours)