Experimental DIY Friction setup

That ought to burn your tire up real quick !!!!
But will be interesting ..... " MORE POWER " !!!!!!

It will be different than a bitty two stroke on a friction roller, that's for sure. My huge 2 3/4" (69.9mm) roller will allow me to run just about 30 mph at the governed speed of 3600 RPM. I've heard from more than one source that the little HF engine can handle 4200+ with no problems. Another nice part about the large roller is better grip due to more area in contact with the tire.

Right now the roller and the engine are down at the machine shop, the roller is being drilled for the engine's crank. More to come soon!

-Mark
 
Got to start my new motor earlier, with the roller mounted to it. Not on the bike yet, just mounted to a test stand. It's much quieter and smoother than I thought it would be, and it's leaps and bounds smoother than the HT setup it will replace. I'm getting batteries for the camera so I can post pics of the build.

-Mark
 
Very good, these engines are REAL available but some will not run without the heavy flywheel. I nearly broke my hand trying to start one that had a loose blade I didn't know about, It would backfire and rip the rope back- just would not run, until I fixed the blade mount ( broken washer).
 
The Beast Lives!

Took it on it's maiden voyage to Quiktrip and back. (about 3 miles round trip) It does not, as yet, accelerate as quick as my HT did, BUT it runs considerably smoother and quieter, and will reach speeds I can only describe as terrifying. On a 35 mph stretch I had a car that couldn't make up it's mind to pass me, I throttled up (With the governor) and pulled away from the car. At it's top governed speed it gives me the heebie-jeebies and I manfully whimped out after about 10 seconds of the scenery coming at me too fast. If you hold the governor around the 1/4 setting it putt-putts along at a nice 25mph-ish speed. I had to help it up a fairly steep hill, the engine slowed down to the point I thought it would stall. The roller didn't slip at all, but ate up my 15 year old Panracer MTB tire. I think a smoother tire would help a lot. I also need to cut out part of the mount, so the bolt that holds on the roller doesn't rub.

An interesting note, the engine is easily bump-started. I wasn't expecting that.

-Mark
 

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Slight problem I'm having... When I throttle the engine up, it just dies. if I'm rolling, then the engine starts back up after a few seconds. Does the HF 2.5 engine have problems accelerating normally, is it supposed to be only one speed?

-Mark
 
Took the machine on a decent ride today, about 5 miles. It's so much smoother and quieter than the HT than I thought was even possible. It seems like the top speed is right around 28 MPH, this is using the governor, not applying the throttle directly. The best way to run the engine seems to be by simply shutting it off when you want to stop, instead of disengaging it from the tire. When you want to start, you begin pedaling, the engine starts at around 6-8 MPH and starts to pull you along. At low speeds the front tire nearly leaves the ground during the power stroke. Roller slippage is a non-issue, but I haven't ridden it with a wet tire yet. It will be ready to take me to work in a week.

-Mark
 
Tinker:

Nice work! I really like that HF engine too. How did you handle installing a clutch? And yes, you really need like cruiser type tires for that. The BMP guy I got my kit from told me that mountain bike tires will get chewed up in no time at all.

I want to build something next time with an engine like that but I can't figure out the clutch part yet. I saw a Youtube video of a guy riding a trike that had a lever to engage/disengage but it looked really dangerous if one needed to stop real fast, no time to grab the lever. But, he showed that when at idle, he was doing over 8 mph, and no loss due to clutch. So, I am very curious as to how you rigged a clutch up to this.

Best of luck with your MB

Bill
 
ok it was aways back but a side shaft engine with the dipper repositioned will oil everything just fine on its side(horizontal)? awesome setup you have there.
 
Tinker:

Nice work! I really like that HF engine too. How did you handle installing a clutch? And yes, you really need like cruiser type tires for that. The BMP guy I got my kit from told me that mountain bike tires will get chewed up in no time at all.

I want to build something next time with an engine like that but I can't figure out the clutch part yet. I saw a Youtube video of a guy riding a trike that had a lever to engage/disengage but it looked really dangerous if one needed to stop real fast, no time to grab the lever. But, he showed that when at idle, he was doing over 8 mph, and no loss due to clutch. So, I am very curious as to how you rigged a clutch up to this.

Best of luck with your MB

Bill

Actaully... I don't have a clutch. I originally set it up this way to just see if the engine had the power to move the bike with such a large roller. I pedal the bike to start the engine, around walking speed it will start to pull me along. I keep pedaling up to about 8 MPH and than apply throttle, and it pulls me away! I normally run it right around 25-27 MPH, the engine seems to like that speed. It will run 30 with no problems, and my top speed on the flats is about 37 mph which is really way too fast. When stopping, I have a kill switch wired up to the handlebars, and I stop the engine just as the bike gets down to walking speed.

The friction drive doesn't really work too well for the large of an engine. There is too much torque, it will slip the roller fairly easy, and there is quite a bit of tension on the roller. The least bit of a puddle and it slips. I think I will use this engine on a chain drive, I'm going to use an old 7 speed rear wheel cassette and axle for a jackshaft, and put the entire thing over the back wheel.

-Mark
 
ok it was aways back but a side shaft engine with the dipper repositioned will oil everything just fine on its side(horizontal)? awesome setup you have there.

Thanks for the compliment. :) Yes, the vertical shaft engine will oil itself just fine if you first put a oil dipper from a side shaft engine in it. The rest of the parts (For the briggs and stratton engines) are the same. The only problem you might have is the flywheel, some of the vertical shaft flywheels aren't as heavy as the side shaft flywheels. The engine will still run with the light flywheel, but be prepared to have the starting cord snatched from your hand occasionally when starting.

-Mark
 
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