Another Friction Drive, Last One I Swear!!
- Thread starter cannonball2
- Start date
Hey, thanks C2 
Maybe I can play around with the location of the pivot point on my clutch to make it work. I can probably trim a half inch somehow. Either that, or I'm fabricating something, I guess. But a pre-made lever will look so much better.
Off to research!
Maybe I can play around with the location of the pivot point on my clutch to make it work. I can probably trim a half inch somehow. Either that, or I'm fabricating something, I guess. But a pre-made lever will look so much better.
Off to research!
I'm new and a complete novice and plan to build my first bike this Winter. I really want to use the DF Scissor Lift design and was wanting to know if there are any kits available. If not, I will try to have it fabricated. I have looked at kits and had seen one years ago and from what I recall they were constantly having to readjust the roller to keep enough pressure on the tire. I will be primarily using this bike off-road so I want to be able to adjust pressure on the go, since I am guessing this will be an issue.
If there aren't any kits available any additional design information would be greatly appreciated. Can't wait to get this going but I would really like to do it right.
If there aren't any kits available any additional design information would be greatly appreciated. Can't wait to get this going but I would really like to do it right.
The scissor lift is very simple, just two pieces of flat iron with a cable pull point in the center joint and a pivot point on the engine frame and the bike frame. Cable pulls the center point up goes the engine.
Its here in post #1 if you missed it.http://motorbicycling.com/f36/another-friction-drive-last-one-i-31318.html#post301006
I marvel at your project, the design for its simplicity. I admire a lot and I think gives stability to the engine only with the left arm fixed interpete not hardly believe in its function, which is a great wonder, without a doubt congratulations
cb2;
Can you bump start the motor by dropping it on the wheel?
Does the spring have enough tension to turn over the motor?
About how fast would you have to pedal to, before dropping the clutch?
Can you bump start the motor by dropping it on the wheel?
Does the spring have enough tension to turn over the motor?
About how fast would you have to pedal to, before dropping the clutch?
I have never tried to drop start one of the Lifans, I just use the recoil. I believe maybe Deacon drop started his. I will give it a try next time out. The Lifans have a great deal of initial compression, a good bit more than an HF engine. I have enough down force to kill the engine with the brakes even at a higher idle, so it follows it should start. Will let you know.
No dice yet on a drop start. I say yet because the bike has a new tire, the tires tend to be a little slick until you get a few miles on them, still might work.
great build, do you get a lot of vibrations. is the motor really secured... and could u possibly give me a detailed description on how you secured your wooden drive roller to the shaft?
Thanks DBM. The roller is retained with a bolt and large washer in the crank end. The washer is sized so it slips over the crank shaft. There is a piece of rubber about 1/4" thick on the engine side of the roller against a similar washer. When the bolt is tightened the roller is compressed into the rubber disc providing positive drive to the roller. This bike runs a 2.6" roller for speed. Tops around 40. Not as good of hill climber as some but reasonable on most hills.
Didnt answer all the question. The motor is basically vibless as are all my Lifan FDs. The engines are smooth, but I believe the tire absorbs any vibes there are while being driven. I get a small bit of vibes in the pedals at max RPM. The engine is very secure. Wouldnt be on there long if it werent. This one rides/pivots on a 1/2" bolt which is securely clamped/bolted to the frame. My Mongoose MTB with a similar drive is well over 2kmi with no issues with the installation.
Love the simplicity. Do you prefer the lifan over the predator for this style? I'd love to build one of these but the way Idaho defines a moped it can't have a manual clutch. already pushing it on the engine size.
Both are excellent engines and have their advantages. I have more Lifans and time on them than Predators. I think the Lifan may be overall a little more compact(minus the tank). I believe the Predy revs a bit higher and the Lifan makes a bit more torque due to a longer stroke. The only large engine I have used for direct FD has been the Lifan, but I dont know why a Predy wouldnt work as well. I have wondered if a lifting mechanism is a really a clutch, or simply a way to disengage the engine for pedaling? When in the drive mode the engine is a clutchless direct drive. Guess it depends on who you are trying to explain it to.
hmm good point. I re-read the statue and it says
To me, lowering the engine would be just engaging the the drive system. So thinking about this again, it would be OK.
Yeah, the lift seems to be acceptable under the law. While a hand lever is the preferable method of actuation it probably looks too much like a true clutch system. Maybe the lever method would be better from the legal stand point. BTW I have gotten the Lifan to drop start as was asked earlier in this thread. Much to my suprise! That would be a good argument for the lift as part of the starting system. Especially if the recoil was removed.
Now that's what I want to see my idea is similar to yours, excluding the hinge, my idea will require a hinge to mount the motor a angle bracket etc. But I will be taking your idea for the lift so that's 3 ideas to make one good one.
Mine is clean cut your is diamond cut and the guy who started the door hinge idea was an ok idea. I was thinking cable lift. As for the gas tank how did you mount it on the engine? Isn't that dangerous?
*Bing* I'll take roller for 200 alex, I need that I don't want some peg eating my tire away, I prefer rubber on rubber.
