engine torqued to left on motorized bicycle

ive been riding this motorized walmart bike for nearly 4 mos, and its done ok, but this direct wheel on tire drive isnt that efficeint, and now it appears that after changing the rear tire (again) and mounting my basket that its torqued or leaning way to the left, as can be seen in the photo. it is much more apparent in reality, as its hard for me to get htis thing oriented straight for the photo.

It requires constant adjustment of course, becuase of wear etc, but has been pretty reliable albeit very weak power and traction wise (shoulda got a direct chain drive type).

But now, after a friend and i changed teh tire it and readjusted clearance, it appears to be leaning excessively. I cant see anything loose in the mounting bolts or anything obvious. Maybe it jsut does this over time and i jsut didnt notice it till now.

Anyone out there familiar wiht such bikes think this is a bit odd, or jsut part of the territory. I thought i may have to remount the engine on the mount, but it appears to me that the mount itself is torqued a bit, and i may need to get a new mounting plate. Just wondered what any of you guys may think. thanxx....

this is my ride until i get a Tomos ST in a couple of weeks (hopefully). And it will still get alot of use in town, as theres some places i still will need to use it.


Re: engine torqued to left on motorized bicycle

oh, i forgot to mention that until now,it has been alot more perpindicular to the tire, almost a 45% angle. It still runs ok, but im concerned about uneven tire wear, which is a factor in this kind of mount.

another view of the engine arrangement can be seen in the extra attachment.


Re: engine torqued to left on motorized bicycle

There is something wrong with your mounting brackets. I have the same engine, but my mounting brackets are totally different. Either something is bent, or out of adjustment. Also, my roller is metal, and goes all the way across. and is supported by bearings on both ends. My roller is straight across the top of the tire. Peace. Jerry.

Re: engine torqued to left on motorized bicycle

Steve Williams /

those brackets are the biggest bodge i have ever seen.they are the root of your problem.

Re: engine torqued to left on motorized bicycle

yeah, the brackets are a bit.......of a rig. But this is what the company sent me when i ordered it, and it appears to be built the same way as the photos on their web site as well as the instructions. A friend of mine who used to race dirtbikes and mod them, as well as built the bikes at walmart, helped me put it together (and changes the tires-im like a monkey making love wiht a football when i try that). Weve been all over this thng without finding much that is loose of outta alignment that would cause it to change that much in such an amount of time.

Does yours have the drive shaft supported on the ohter side of the engine mount? It seemed to be a bit weak to me when i got this thing, but the engine does kinda put some wieght on one side.

it originally came wiht wood drive wheels, if you can believe that; they wear out in about 2 days. they sell the composite ones seperately which dont wear any, but the all weahter "stone" wheel is like a grinder....my last tire was worn smooth and paper thin when i replaced it after 2 mos. I test rode it today all over this mountain, and it didnt slip too much, but man i wore myself out trying to get up a couple of hills. totally useless on hills of any incline over 2%, and crawls up that.

Ill just be glad when i get the ST.....but i still have to use the bike for some places around where i work partime in town.

thanx .....

Re: engine torqued to left on motorized bicycle

I can't tell exactly what it is from the picture, but something is definitely bent. Notice how the whole motor is crooked. Mine is mostly homemade, the roller is made out of a transmission shaft, and is solidly supported by caged roller bearings on both ends. I have 1 piece heavyweight steel supports on both sides of the motor mount. The mount itself is made out of approx 3/16" thick steel channel from part of a commercial mower deck. I also had problems with tire wear, because I was using tires like yours. After going through several tires, I finally switched to a tire with a smooth ribbed tread design, with no knobs on it. Tire wear has decreased substantially. But back to your problem. It looks like the mounting brackets are simply not strong enough to hold everything straight when you put tension on the drive roller. I just don't see any way it will work without the roller shaft being supported at both ends. The one good thing about it is the engine. The Tecumseh TCII is a damn good engine, better than some moped engines, and 50 times better than a weed eater engine. It is a little noisy though, but would probably take you across the country and back if you can find a solid way to mount it, and use the right tire. A Solex (I have one) uses a friction drive on the front wheel, and the tires are supposed to last 5000 miles.

Re: engine torqued to left on motorized bicycle

see the above photo for a view of hte whole thing. I didnt know about the tire design concept, as i looked for somehting a bit smoother at walmart (all i could afford rt now) and they all had knobby tires.

I wish i could figure a way to support it on both sides...but this is a dimension edge product from montana and was designed this way. i think its site is www.bikemotor.com but i could be wrong. they have several mounts like this for several engines including some 4 cycles.

I cant figure how it just started looking this way, but im pretty sure the mount is jsut bent from stress. It worked pretty good today as i drove it all over the place, but tire wear is gonna get pretty iffy. thanks for the observation. Your homeade one sounds pretty interesting. I thought from the beginning that the shaft should be supported on both sides.


Re: engine torqued to left on motorized bicycle

In the picture from behind, it sure looked like the mount was bent. The engine is tilted way to the left. (from behind).If you look it over good, it should be obvious what the problem is. Peace. Jerry.

Re: engine torqued to left on motorized bicycle

I went to that site and checked it out. You have a good motor, but the mounting bracket and drive roller setup are junk. It will never stay in place that way. You need to find some way to reinforce the mounting bracket. Peace. Jerry.

Re: engine torqued to left on motorized bicycle

Should be simple enough, ask around for anyone who can weld. (automechanics, fix it places, even your local hardware store probably has a list of privately owned repair business) That person should also be able to grind/cut. Buy them some rolled flat steel or square tubing (flat steel should probably be 1/4) and whatever else they ask for. Hand it over to them with $30 (give or take depending on time spent on it).

as far as the roller wheel and wear...iunno, ask someone else.

Re: engine torqued to left on motorized bicycle

yes, advice taken and i appreciate it. I kinda considered it was a design flaw. my engine works pretty good, but it wants to idle wide open sometimes after ive had it engaged. that thing screams when i disengage it, which attracts a bit too much attention. Ive adjusted the little screws that controls that, but it must jar back open. However, after a few loud seconds where the kill switch doesnt even work, it will go back to normal. Really odd.

I gotta find some materials and try and get this modified to be supported on both ends. thanx.....

Re: engine torqued to left on motorized bicycle

i also need to figure out how to attach it to a hole in the other side of the improvised mount. I think the steel in the supplied one is too thin. I also need to be able to change out the drive wheel to the all weather stone one...ive needed that several times when caught out in the rain....like a few weeks ago when i wound up changing it in freezing rain that had been light snow moments before. I discovered that my collapsable basket wasnt as easy to move outta the way as i thought, and the main bolt got out of allignment.......

took 45 min for what normally takes 5.....in the freezing cold and partially in the rain. I liked that.

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