why I love friction drive

[deacon]

I decided to check on the little engine that couldn't today. The bumble bee engine started up and throttled up just fine. I had already removed it from it's mount so I had to make a holder in order to check it. I don't trust it, so I won't be using it really, but I do plan to do a test with it. I always wanted to know, if I could use a gasoline engine to run the rear wheel of an electric scooter. I use those to push my ebike.

There are some thing I do like about the wheel on a wheel. It is silly looking, but it does work well. It's probably the rubber on rubber connection that makes it work.So in a few days I should know something about this one as well.

 

[deacon]

I had been wanting to try something and finally all the pieces came together, so I built a drive using a scooter rear wheel and a gasoline engine. I haven't started the engine yet, but I tested the engine yesterday but not attached to the wheel.

I have the small 11 tooth sprocket on the gasoline engine, and I think a 44 tooth rears wheel sprocket. I got the engine mount built and the wheel attached. The chain has been cut and attached so now it is just put a gas tank back on the motor and fire it up tomorrow.

I figure there are two possibilities. One it will work just as I planned or two it will fly apart. Either way I add more information to my library of useless stuff.

 

[deacon]

Finally something worked just as I envisioned it. I had a bit of a go with the bike getting all the stuff adjusted but once I did, it ran just like I expected. I expect that it runs as good as the fancy friction bikes, even though it is running with a small slightly damaged engine, It pulled all the hills I put it on. Yes it pulled them at a walk but it did pull them. Just a few pedals and it would go right up them. I like it just as well as my Big bike for different reasons.

Now it has me thinking pit bike engine with small electric scooter rear wheel. Everything should be there that you need.

 

[deacon]

I have been riding the new bike I built and it is the best design yet. I should have done this to begin with. I knew from the ebikes I built, that the rhino design was a winner, I should have at least tried it with gasoline. Now that I have I am very impressed with it. It does extremely well with the relatively low powered bumble bee bike. I think that motor is comparable to the ryobi weed eater engine. A helper size bike. It is fun to ride but if I were going somewhere I would ride the BAM bike.

I should give some thought to a BAM rhino.

 

[deacon]

after all the experiments, I think I have the bike design that I am going to build to ride into my golden years. Okay it's just gold paint, but I have it figured I think.

First of all what I learned.

1. The lever lift system will lift a 2.5 hp motor and drive easily.
2. The best friction drive is a chain drive friction, wheel on a wheel (at least for me)
3. I can mount a #41 sprocket directly to a 5/8 drive shaft and then to a chain on the rear coaster brake wheel with the rim removed. The coaster brake wheel hub is my choice because it has the sprocket already mounted on the hub. Also they are easy to find in almost any kids bike in the thrift shops cheap.
4. I can cover the coaster brake wheel hub with the tread from a tire and glue it down with gorilla glue. I have one on the wheel of a scooter and it is holding up well.

The ideal frame is a 24" coaster brake bike with a hand brake on the front as an emergency brake. One throttle and one brake lever on the handle bars to keep it simple.

The motor weight on one side of the drive mount and a spring and turnbuckle to counter balance the motor and i should be good to go.

It is my plan to slowly acquire the items I need and to build the 'ideal' bike when the Tecumseh bike dies. I have no idea when that will be. I have it on a 26" coaster brake bike now and it is fine. The 24" would just be easier to mount and dismount.

My only complaint with the Tecumseh is the idle linkage is missing. That wouldn't be an issue with a new engine.

 

[deacon]

I just rode my bumble bee bike with the scooter wheel drive for about three miles. It is a really fun bike at some where between 35 and 40 cc's. I would build another one of those for my next bike except that I am committed to going to only one bike, when I stop building bikes. It has to be a bike with which I can go to the grocery store should it become necessary. The bumble bee bike would have a real problem with one of the hills and with a trailer it would be almost a disaster in the making. The only reasonable thing to do is to build the bike I mentioned n the last post.

That's the thing about motor bikes, what are they exactly. Each of us has to define that for ourselves. Mine is for transportation independent of my wife's car. Since the doctors won't let me drive a car and it makes sense not to drive a car, I need a way to go to the store or to the hardware store if I want. The motor bike is ideal for that. It can sit in my garage for days at a time, then I can hop on it and ride down for enough groceries to fill my small trailer if I want, or run to the doctor a couple of miles downtown, should that be an issue.

With the big bike, I could even ride to my daughter's house about ten miles each away, not so the bumble bee. So I'll keep the bee for exercise and fun but build a solid bike like my BAM bike now. I want one that requires a minimum of upkeep so I want to go with a new motor for sure, if the Tecumseh ever dies that is. I know I built my first bike with no end purpose in mind at all. I have built many of them with no real use in mind, but now if I only have one bike, it has to do it all.

 

[deacon]

for the last bike I hope to build I have already got the engine even though others bought it cheaper I got mine for under a hundred bucks. 2.5 hp from habor freight shipped to me.

I promised to get rid of some bikes before I built a new one so I'm waiting for a bike to die. In the meantime I am getting the drive ready. I did not say that I wouldn't have it all ready, just that I would build a new bike. So this is what I am planning. When the engine comes, I have should have a sprocket all ready for it. A #41 ten tooth thing. I will use that to drive the hub of a coaster brake wheel. That wheel is about 1.5 inches in diameter but the sprocket on it is about 4" in diameter. I don't know what that will do but I don't think it will have much effect since the drive is friction. I also bought a new bottle of gorilla glue and a couple of hose clamps. I have already attached a piece of a wornout tire to the coaster hub. I also trimmed off the brake lever, rather than take the hub apart.

so when the motor arrives I have to build a frame for it and one for the coaster hub and put them together which I did for the smaller motor of the bumble bee, so I'm pretty sure this will work well. I will have a lift system to use as a clutch.

Now if a really nice 24" coaster bike shows up at the thrift store before one of mine breaks, I'm going to buy it. If not when one of my bikes break, I am going to buy a new one from Wally-mart for eighty bucks or so. Even if everything is brand new, I will have under $250 in the bike.

 

[deacon]

I am pretty sure this time that bumble bee bike is DOA. It locked up tight twice. I disconnected everything and it seemed to work so I reassembled it and it locked up after half a mile. It ran crappy before it died as well. I'm going to give it one more try without the chain drive option to see how it does with just a direct roller drive. If it runs poorly I'm going to figure it is dead too bad but life happens i guess.

 

[deacon]

yep I remounted the engine and the drive shaft wobbles. Obviously the bearing is gone. I suppose it is from the engine being dripped on the tire rather than lowered gently. Gentle is going to be difficult but I'm going to work on that tomorrow. Also I think I am going back to direct drive only. drive wheel attached to the drive shaft. Im not sure the chain drive didn't somehow put some wear on that bearing.

 

[deacon]

Like I always say I love friction drive because it's simple and it works. Anyone can do it with a minimum of tools and parts. So today I would like to give my opinion of the HF 2.5 hp as a friction drive engine.

Let's begin with the most obvious.. it is legally too big most places. But then it is on any of the bikes we ride in most places.

It is way heavy.. I put mine on a twenty inch rear wheel to keep it low and easier to control. I might go up to a 24" one day, if I run into a good coaster brake bike cheap. But there doesn't seem to be any real advantage except I wouldn't look so much like a circus bear.

The muffler is in the wrong place for a friction drive bike. As it come from the factory it blows hot air on the rider... pretty much like I'm doing now. But the muffler is held on with three bolts and can be rotated on the pipe. I was able to turn mine away from me and now it is okay.

The gas tank feeds from the center, so the engine has to sit more or less level to feed properly. The gas tank also has a three point connection arrangement, so it is possible to raise it with extensions to make it more or less level. MIne leaked and I didn't like that it was touching the muffler after the two were modified so I switched it for a tank I had laying around. That seems to have done the trick.

The drive shaft appears to be strong and its a pretty good length. I picked up a heavy sprocket with keyway. I welded a 1" ID smooth pipe nipple onto the sprocket. I installed the sprocket then got a longer M6 bolt from the hardware store so that I could put a fender washer and bolt through the outer end to support and keep it from moving off the shaft. I probably didn't need to do that, but it seemed like cheap insurance.

The greyhound has mounting bolts both on the side and the bottom. I chose to use the bottom bolt holes to build my frame. then I attached it to the bike with a henge and hanger system. A spring for tension and a cable and lever to lift it and it was finished. Believe it or not the lever is very easy to raise and lower so the weight is less an issue than you would think.

I have put about twenty miles on it so far and I do love the beast. I added a second kick stand under the motor and I am pretty sure I will use it almost exclusively with the trailer I built. The trailer adds a lot of stability because of the weight issue with the motor..

That's my first take on using the 2.5 greyhound.

A couple of general observations. It's my first 4 stroke and I like the noise reduction. The gas and oil prospect it nice. If I get out a can buy a half dollars worth of gas to get home. It starts easy right now and the throttle wasn't all that much trouble, but I expect I haven't seen the end of that issue yet.

Well those are my thoughts on the greyhound 2.5 motor. I could live with it at about two hp with more rpms I think, but I love the beast. It has mule power I think, not so much horse power. Since I am running it with a smooth drive wheel, I can get some better performance by roughing up the wheel, but that adds tire wear and the bike does well enough as it is.

 

[moonshiner]

good read on friction drive deacon , i know what you mean about the killer hills i have a bunch where i live too , i am going with a friction drive on my first motorized bike ...

 

[deacon]

if you go with a kit I honestly don't know much about them, but right now that four stroke 79cc from harbor freight is a really easy engine to build a friction drive with. There were some changes necessary, but so far it seems strong and willing to run almost all the time. Today it died, but I had let it run out of gas. It started right back up and ran just fine.

I am also in the phase of now that I know it works, I have to go back and do all the half A$$ jobs the right way. It is a challenge but it's got me a couple of more days building before I have to struggle to find something to work on again.

 

[deacon]

This is a little about the 2.5 hp HF bike I built but a little about friction drive in general. I took the new 2.5hp to the lake. It's about a three mile ride there and I noticed when I left home it felt like it had more vibration than last night, but I decided that it was my imagination. WRONG.

When I got to the lake the chain fell off and continued to do so every few yards. Now my primary brake is the coaster brake but I do have a front clamp down brake. That being the case I put the chain on and gave it a push with my leg. I dropped the engine and managed to get it going. I rode the bike all the way home like that.

Friction drive is just so simple. IF the motor turns odds are the bike will go. Just so you know the rear wheel was loose, which shook the bolt out of the coaster brake lever, all of it together loosened the chain ring. It was a mess but I got it home without pushing it this time. Seems to me that odds are one or the other will work.

 

[deacon]

I had a chance to run the friction drive 2.5 hp with the one inch roller and found it to have all the power I could personally ever want. I know lots of guys have the more power, more power, grunt, grunt thing going. I don't blame them at all.

I think the 2.5 might be a little more than necessary to do just the minimum I want. When the 2.5 is really on it's game it will not only take the biggest hill in town without breathing hard, it will actually accelerate going up it. I don't even have the best roller and tension settings right yet. So I'm thinking it might really work just as well with 2hp or even 1.5 maybe.

It's something to think about. I bet a 1.5 hp with a scooter wheel would work just as well for what I want. Something to climb the hills at almost the same speed as I feel safe on the flat, while not straining the motor to it's limits. The bumble bee would almost do it.

I would almost bet money that one of those small generator or auger motors hooked to a scooter rear wheel assembly would run quite as well as this bigger motor. Just my thinking.

 

[cannonball2]

That all depends on the gearing in the scooter trans. That is a huge drive roller. The 2" roller on my Lifan bike is in the area of 14:1 which is good for 2.5hp. It will do ok with a 12:1 but wont climb hills as well. With the 14:1 it will climb just about anything out there, and still easily cruise around 23-24mph. I am thinking 2.5hp is the best all around hp for direct friction drive, at least with a 4stroke industrial type engine. After riding the very quiet, smooth and powerful Lifan bike, Im not anxious to deal with a screeming, vibrating 2stroke, excepting my Solex which is smooth and queit.

 

[deacon]

And I love the noise smoke and stink of a two stroke, but I willingly admit that I love the 2.5 HF engine as well. It is just so effortless went it runs that it always feels that it is holding back. I open it up now and then and yes it does do pretty well with the one inch roller as well. I would rather run at something over half throttle so it is probably fifteen miles per hour usually. It loses very little speed going up hills unless they are monsters. It never gets so slow that I can pedal it unless I kill the throttle completely and let it coast. I swear it will climb hills unaided that my china kit almost hit stall on.

I know the owner of the bike shop here who sells mopeds as well as bikes. He said the older 4stroke at fifty cc were awful at hills. I find my friction drive to be just fine at 2.5 hp which is half again the cc of his scooter. I would think that 50cc 4stroke in this quality engine, should do just fine as a friction drive on a bike.

I would love to find a 50cc four stroke engine to try. The kit on ebay and around is just too expensive considering we can build a very, very strong friction drive now for about what they are charging for their little kits. I know riding theirs would be easier, but frankly it just looks like more to go wrong.

 

[cannonball2]

I have a 50cc Hauseng 4stroke engine and it has been good. It is geared around 17:1.(belt/chain drive) has a 30+ top speed and climbs hills well. What it has over the industrial type engines is rpm, 7K+. A friction drive with one of these would be good, should climb well with a smaller roller, and still have good top end due to the rpms. But, you could buy 2 HF engines for the cost of 1. I dont think there is much reason to use a smaller engine, except maybe legality. I have a 31cc 4stroke friction kit and it works well. Not a great climber though. Its all I would need if I lived in Fla. Thinking of a 24" Cranbrook from wallyworld for the Hf engine, toying with the idea of a front mount.

 

[deacon]

Front mount yikes the weight would scare the heck out of me with that. One thing about the HF is that it drag starts really really easily. When I had the lift cable break. I stopped and started it all the way home. pedal motor down and start from a dead stop an it started every time on a single pedal.

 

[cannonball2]

You dont notice it on the front anymore than on the back.

 

[bighat]

Had my Bee for a couple weeks now. Ride everyday. Maintains cruise at 40km+ easily. Pedal assist going up steeper hills without breaking any sweat. Lightweight, RELIABLE, versatile and made in U.S.A. Virtually maintenance free and solid engine. It helps that I'm only 150 pounds.