Huffy Cranbrook Project

[wtwrestling07]

I just built my first motorized bicycle, so i thought i would join this forum. I bought a Huffy Cranbrook on sale for $88.00 at walmart and bought a 80cc (66cc) Bicycle engine kit off of ebay for $145.00 with free shipping. I got my kit in the mail friday and had it all put together in a few hours except for sizeing the chain and drilling the handle bars. I had to go out the next day and buy a used drill and a punch for $5.00 to finish the project. I got it all put together by saturday morning and took it outside to test it out. At first I was having some trouble with the clutch arm then I got it working. Fired it up and it was running good. Rode it around the parking lot a few time then shut it off to let it cool down. Fired it up again and rode it around a few more time and it was still running good. After I tried to fire it up a third time the chain poped off and got stuck in the sprocket, so I had to go and get a screw driver and dig it out and put it back together. Well after about 3 or 4 more time of digging the chain out of the sprocket, I noticed I stripped the top bolt of the chain tensioner, so I went to lowes the next day to go buy some new heavy duty ones for it. After I got those put on, the chain is still poping off. I also noticed after the chain poped off so many times it messed up my back tire allignment so I had to straighten it back out. Still the chain is poping off. The only other thing I can think of is the front motor mount is not completely straight and kind of leans to the left a little b/c the large diamiter down tube bracket that was in the kit dosnt fit right. One side of the U bolt is hiting the engine so i cant tighten it down the way it should be without grinding half the threads off and i dont have a grinder. Its only off by a hair or so. Even with the engine mount the way it is i dont think it should be jerking the chain off the way it is. So with all this said, I am wondering has any one else ran into a problem like this or is there somthing I am missing or not seeing? I have read alot about using the kit as a daily driver and them being somewhat reliable so I know somthing isnt right. I am going to try to upload some pictures of the bike and the front mount and chain tensioner so you can see what im talking about. I am also thinking about buying a Large Universal Front Engine Mount from SickBikeParts.com to fix the mount problem, I just dont know if that is gona fix the chain problem.

 

[Dave31]

Welcome to the forum wtwrestling07

Chain that pops and falls off is a sign of a alignment problem. Three things need to be aligned for perfect chain true. Motor, sprocket and wheel. Four I guess if you are using a tensioner.

 

[greaser_monkey_87]

You should install a front brake. A cantilever brake can be mounted to the fender mount hole on the fork, and the fender can stay, but you should reinforce your fender mounts also.

 

[mapbike]

nice looking bike.

 

[mapbike]

I just built my first motorized bicycle, so i thought i would join this forum. I bought a Huffy Cranbrook on sale for $88.00 at walmart and bought a 80cc (66cc) Bicycle engine kit off of ebay for $145.00 with free shipping. I got my kit in the mail friday and had it all put together in a few hours except for sizeing the chain and drilling the handle bars. I had to go out the next day and buy a used drill and a punch for $5.00 to finish the project. I got it all put together by saturday morning and took it outside to test it out. At first I was having some trouble with the clutch arm then I got it working. Fired it up and it was running good. Rode it around the parking lot a few time then shut it off to let it cool down. Fired it up again and rode it around a few more time and it was still running good. After I tried to fire it up a third time the chain poped off and got stuck in the sprocket, so I had to go and get a screw driver and dig it out and put it back together. Well after about 3 or 4 more time of digging the chain out of the sprocket, I noticed I stripped the top bolt of the chain tensioner, so I went to lowes the next day to go buy some new heavy duty ones for it. After I got those put on, the chain is still poping off. I also noticed after the chain poped off so many times it messed up my back tire allignment so I had to straighten it back out. Still the chain is poping off. The only other thing I can think of is the front motor mount is not completely straight and kind of leans to the left a little b/c the large diamiter down tube bracket that was in the kit dosnt fit right. One side of the U bolt is hiting the engine so i cant tighten it down the way it should be without grinding half the threads off and i dont have a grinder. Its only off by a hair or so. Even with the engine mount the way it is i dont think it should be jerking the chain off the way it is. So with all this said, I am wondering has any one else ran into a problem like this or is there somthing I am missing or not seeing? I have read alot about using the kit as a daily driver and them being somewhat reliable so I know somthing isnt right. I am going to try to upload some pictures of the bike and the front mount and chain tensioner so you can see what im talking about. I am also thinking about buying a Large Universal Front Engine Mount from SickBikeParts.com to fix the mount problem, I just dont know if that is gona fix the chain problem.

problem I see is the way you have the rear on that engine mounted, the front mount sitting like it is is gonna be a problem also, the engine needs to be securely mou ted to the frame and your is t done like it is, I have a Huffy build I did back in 2010, one of my best riding bikes, in order to get the engine mou ted like it needed to be I removed the chain guard and put a slightly smaller sprocket on the cranks, a 36T works great, lets the engine settle in lower in the frame and will likely cure the misalignment issue you are having if you will saddle the rear of the engine on the frame like it should be and then order you a large frame front mount from www.sickbikeparts.com, if I wasnt at work on my phone Id post links to the stuff here but it aint hard to find.

getting the engine mountex correctly and securely is the most important part of a build.

map

 

[2door]

Actually I believe the photos are all of the front mount, not the rear. I'm not a fan of 'U' bolt style mounts like that one but if done right they will suffice. The extra length needs to be trimmed off so it can be tightened better.

What I see is a very loose chain. The droop is obvious in the second photo. I'd start by tightening the chain. You want 1/2" to 3/4" of slack. More than that, and just a little misalignment with the sprockets and you'll have the problem you're having.

The tensioner can also cause you problems if it isn't aligned with the chain path. Almost without exception the tensioner brackets need to be bent/twisted to get the tensioner wheel to align with the chain. As they come in the kits the wheel will tend to pull the chain off to one side or the other and cause derailment, especially with a loose chain. Have you given any thought to removing the tensioner completely? Some bike frames will allow that and eliminates one potential source of trouble.

From the photo your sprocket alignment looks pretty good. You'll also want to make sure the rear sprocket is perfectly centered on the hub. It must be concentric or it will cause the chain to tighten then loosen as the rear whel rotates. That too can cause a chain to derail from the sprockets.
Good luck.

Tom

 

[mapbike]

after looking at the pix again I can see that they are all of the front mount, what threw me was not seeing where the wires come out from magneto, I see now that the pic is reversed and that is what tricked me.

map

 

[jonnyp929]

Do NOT cut the mount. It will mess up the threads. Just take the metal plate and flip it so the u bolt is on the top of engine. About the chain popping off, it is beause of poor sprocket alightment. This will take acouple of hours to make it straight. Take the gas out of the bike and put it upside down so rear rim is facing up. Then loosen the sprocket bolts so the sprocket can move. Pedal the bike so the sprocket aligns by itself and slowley tighten it. Tighten the bolts oppisite from . Another. Dont worry about putting a front brake right now. If you decide to put parts on it to make it safer, buy a spring loaded chain tensioner. The regular one has the tendancy to go into the spokes if properly not looked after and bearings inside are very cheap

 

[wtwrestling07]

Update on the bike: I got it running great. Runs perfect now. I had to grind off the bottem waterbottle bolt so the engine can sit at more of an angle, and I turned the U bolt the other way b/c I noticed I had it on upside down. I also noticed I had the sprocket on backwards so I put it on the right way and centered it better. I have been reading alot on this forum about chains poping off and chain tensioners and started reading on a post that said to get rid of the chain tensioner alltogether and put some shims between the engine mount and it worked perfect. I have been riding it around for the last couple hours and its awsum. It's still riding kinda rough because its a brand new engine, its definatly getting better the more I ride it. I think im still gona get the front motor mount from sickbikeparts.com and the set of machined shims from venicemotorbikes.com, that way for sure the engine will stay put. I got alot of plans for the bike just gona be awhile before I get it all put together. For now I just wana focus on keepin the bike running. Only problem right now is I dont have any brakes. Coaster brake arm wouldn't clear the bolts and I dont have any way to bend it. I dont even have a garage to work in right now because im renting a room. Im gona go to the junk yard in the next couple days and see if I can find an old bike with caliper brakes I can take off or just order some off of ebay or amazon. I think there only about $15.00 or so for just the rear or about $20.00 for both with a dual brake lever. One thing for sure is im gona put some 25" ape hangers on it.

 

[ckangaroo70]

Nice looking bike! Have one myself and getting the chain components fine tuned can take some time, but once you get it tracking smooth....you will really enjoy the bike.

One thing I do is once I have the chain tensioner where I am happy with it is to put some JB weld one the frame where the tensioner mounts so as to prevent it from ever moving in towards the spokes. I have done this on three different builds and the JB weld has always maintained its bond to the frame.

Another thing I have found is when you mount the back tire, the chain seems to track much better if you just slightly cocked the tire to left side. Should only have about a 1/4" of clearance between the chain and the tire sidewall. I also put a slight twist in the tensioner mount as well if it appears to be out of line with the chain tracking....which it probably will due to the angle of the frame tubing where the tensioner mounts.

I usually try to maintain chain tightness of about 1/2" to 3/4" movement if you squeeze the upper and lower chain together. As you have found...you need to mount the rear sprocket so the teeth are furthest out, and you will also want to clamp some sort of guide on the frame that goes up within 1/8" from the sprocket surface so you can spin the tire and check for sprocket wobble. You can usually fine tune this by putting a bit more torque on the spots that are running out away from your guide.

Really take your time to get your chain where it will track smooth not only running thhe bike forward, but also backwards. Once you accomplish this I think you will be quite happy. Enjoy your new cranny and I hope you have many miles of happy motoring!

 

[mapbike]

Here is how I did the Idler/tensioner on my Huffy, been holding up perfectly since 2010, just a piece of flat Aluminum an idler wheel I made up from a skateboard wheel, a couple bolts, some Nyloc nuts and if you'll notice I drill a small hole through bracket and into the frame tume and install a small sheet metal screw with some thread locker on it, a guaranteed solution for stopping the bracket from rolling over into wheel spokes and it does not compromise strength of the frame at all having the single 1/8" hole in that frame tube.

Map