New guy, new bike, new engine kit

[WdSjw]

I went through the trouble to drill a small hole in the handle bar for the throttle grip, then the cheap plastic nub just broke off during installation. So I popped the bubble wrap and just used the plastic to keep the throttle handle in one place. These kits do have some really cheap parts, but they are fun once they are installed. You might as well just break that nub off and don't even bother drilling through the handlebars. Other cheap parts in my kit were the studs for the front motor mount, one was actually bent when I received it in the mail. And the big fat chain that comes with the kit is ridiculously large and rubs on the frame and the tire. I was missing the cdi, a critical part. I ruined my back wheel trying to take apart the coaster brake and putting it back together. I just couldn't get it back together because I couldn't remove the sprocket, which is kind of cheaply made anyway, in my opinion. The kits should come with a better alternative than drilling through the frame to mount the engine. For the price and fun of a completed motorized bike I can't really complain at all because I love my MB, but the parts are cheap.

 

[Zack01GC]

My nub for the throttle is metal. I tried pulling it out or twisting it off, but it wouldn't budge.

It seems as if my kit came with a large downtube adapter similar to the ones people are putting together. Piece of steel with a u-bolt (muffler clamp). One less step in the madness I guess.

 

[WdSjw]

I just used regular bike chain on the motor sprocket side. It's easier to shorten and work with. And I don't have to bother with that cheap tensioner anymore. I am curious if regular bike chain might break on me though. It would be cool if other members could chime in here a tell if regular bike chain is strong enough for the engine. It seems so for now. The cool thing about having a multi gear sprocket on the pedal side is that I can get both the engine chain and the pedal chain tight together easier. Plus I get to have freewheel, I can stop if I am standing up on the pedals.

 

[Zack01GC]

This is turning into be the nightmare build from ****. What I thought was going to take an evening has turned into 4 days putting together... taking apart... putting together... taking apart... putting together... taking apart. The engine, cables, etc were a piece of cake to install, I'm having a lot of trouble with the rear wheel. The chain is rubbing the tire, the chain is too damn loose (at least my roommate has a chain breaker). I guess I'll just keep pissing with the rear wheel tonight.

I had to basically pull apart my whole rear hub assembly on the bike and rebuild it. Another reason I hate coaster brakes. I'm used to my Hayes Disc Brakes on my mountain bike. I like those wayyyy more.

 

[WdSjw]

I bought my kit with the decision to enjoy the build as much or more than the finish, and I got frustrated too. You should enjoy the build man, because when it's working, if you are like me, you will miss the days when you were still building it.

I actually destroyed my cranbrook hub by over tightening in an inexperienced attempt to make the coasterbrake into a fixed gear. Now I have a mountain bike hub with a few gears to choose from and a free wheel. I could add a derailer, but I don't think the cruiser frame was made to harness a derailer and it's not that important anyway.

Honestly, I think I have exceeded 40 mph on my old fixie, that's without an engine. Too bad it got stolen in front of Boarders in down town San Diego :-( I had pegs on my fixie, rather unique, I'd rather not peddle all the time. As a matter of fact, I think I will build another fixed gear bicycle, to ride in addition to my motorized cranbrook, I am getting kind of fat these days

 

[Zack01GC]

I should just be riding my mountain bike, but that trip back from campus is rough, 1.5 miles all up hill.

 

[Sgt. Howard]

The rear sprocket mounting on the Cranbrook was a nightmare for me- as it is, I'm knocking paint off the inside of the frame with the power chain and leaving black scuffs on my pretty whitewalls with the same. Over the Winter, I will modify the frame and see what I can do to protect the tire. BTW- MY front fender has TWO straps of metal holding it to the underside of the fork

 

[Zack01GC]

Now I'm stuck. If I have the rear sprocket dish facing the spokes, the chain rubs the tire. If I turn the sprocket dish outwards, it rubs the frame (and sometimes the tire, too.) Also have to bend rear brake arm.

What should I do? Try to pry the rear portion of the frame apart for more clearance? Add washers to act as spacers (might not have enough axle for that)... Ugh. Regretting decision to build this thing. How can working on cars be easier than working on this damn bike? LOL

 

[tire]

I will let you all know how it goes. I'm still reasearching the Cranbrook coaster brake fixes/modifications... as well as the engine mounting problems. Want to get them figured out before the bike and motor get here so I know what to do when I get started. It all should be here any day!

zack,

i'm not sure how far along you are, but i will be asking questions because i have the same exact bicycle, a cranbrook huffy. i'm not sure your knowledge base but i can probably help you as well.

i have a grubee gt5 66cc kit coming my way soon. i'm repainting everything and modified the front of the frame so that it accepts a fork suspension. the stock cranbrook has NO suspension, which will be very noticeable on anything other than a smooth surface past 15mph. if you want to see pics of my build, go to the NEW MEMBERS section towards the top and look for my post. i have pictures. i'm sure you could ebay or somehow acquire a front suspension for cheap, and to pay for the welding (if you can't yourself) will only cost 10-20 dollars maximum. i'd recommend this.

austin

 

[Al.Fisherman]

Now I'm stuck. If I have the rear sprocket dish facing the spokes, the chain rubs the tire. If I turn the sprocket dish outwards, it rubs the frame (and sometimes the tire, too.) Also have to bend rear brake arm.

What should I do? Try to pry the rear portion of the frame apart for more clearance? Add washers to act as spacers (might not have enough axle for that)... Ugh. Regretting decision to build this thing. How can working on cars be easier than working on this damn bike? LOL

These people have long axles 10X1X187 I'm sure there are others.
WHEELS MANUFACTURING AXLE at JensonUSA.com

 

[Zack01GC]

Thanks Ron

 

[Eric2.0]

Cranbrook here too and I could see the chain/sprocket wil be a challenge.

Well....these bikes weren't made fo rthis, so I guess it's our duty to figure it out and get clever lol...

If I run into something that works, I will share

 

[Sgt. Howard]

I have the standard 49cc kit with the rubber gussets mounting the sprocket to the rear hub- I mounted the sprocket up against the hub with the teeth out and BOTH rubber gussets inside the spokes. It is not a perfect solution, but it seems to work- BTW, there is a slight dishing of the wheel on the sprocket side due to the tension the gussets add to the spokes that pulls the tire towards the chain- I suspect having a bikeman RE-TRUE the wheels to the right might cure this issue- then a slight tweek of the frame where it grinds there (I would do it with axle in place- I am working on a pusher based on a small turnbuckle with spar cups on either end instead of eyeloops- you insert it at the area concerned and UNSCEW)
Hope that helps
The Old Sgt.

 

[Al.Fisherman]

When I built my first build, I thought the instructions were written wrong. After reading them you can understand why I thought that way. So upon rag joint instillation I didn't think they really meant for the sprocket to be clamped directly to the spokes, besides I just cringe when I think of metal to metal rubbing together, especially something thin as spokes are. So on my instillation I sandwiched my spokes with the rubber pads (by the way the instructions said cut 1 rag joint). Works great, no play, and moved the sprocket away from the center and I have more tire clearance for the chain on my cruiser. Another thing I did after ALL the bolts were tight on the sprocket was to remove one at a time, and replace them with much shorter bolts followed by nylock nuts. Now I have only about three threads sticking out beyond the nut. I realize the long bolts are needed to put this all together, but not needed after instillation is complete.

 

[Zack01GC]

Well, I got it all together and took it for it's first ride!!!

Then disaster struck. I posted about it here: http://motorbicycling.com/f4/made-1-4-mi-maiden-voyage-24075.html#post223804

Can someone help me with the questions? I got hooked on my short ride, and want to get this straightened out as soon as possible!

Thanks

 

[Zack01GC]

Fixed the clutch (chain was just bound up in the housing from too much slack)

Now the thing won't stay running. It kicks on, but dies within 5 seconds. If I give it throttle, it bogs and dies anyway. Also, when I pull the clutch in, it dies. Funny thing is, it ran great yesterday on it's first start up!

This bike has been nothing but a giant pain from the start. I hope I can get it running and enjoy it before it starts snowing.

 

[Tacomancini]

I feel your pain, went through a lot of this myself. Is the idle too low? Perhaps, that is why it is dying out. Other weirdness can be caused by an air leak. You should use grey gasket sealer to make sure that carb is nicely sealed on the manifold. I had problems till I got the carb properly sealed. My carb is the Speed carb(it says speed on the side), with the red cover.

Are you giving it enough time with the choke on? Is your carb set with the c-clip in the second notch from the top of the slide?

 

[Zack01GC]

I'm not sure what you mean about the notch on the carb.

Yeah, the choke and everything was set as it was supposed to be, it ran great yesterday following the same steps. I have the gas mixed about 22:1.

 

[Tacomancini]

I guess the fact that it ran fine yesterday, but stopped doing so well may be the thing to focus on. It could be that the carb loosened up due to riding vibrations, causing an air leak. Teflon tape can help also wrap it around the intake and slip the carb on over it. Some sort of sealant is a very good idea though. Some use silicon, I used the grey gasket sealant from spookytoothcycles.com

If you unscrew the carb top, you'll see the pin with the notches that effectively changes your air/fuel ratio but, yeah if it worked yesterday thats probably not the problem. I'd leave that alone for the moment and check other things.

Could be that you aren't getting enough spark. Make sure that your electrical connections didn't come loose. The clips connecting the engine to the cdi can come loose. Most recommend that you solder the connections. Also its a good idea to get rid of the stock kill switch as it often causes problems with the ignition. I kill the engine by putting on the choke. I had a cdi box that died on me, similar symptoms, just couldn't get the engine to really fire up. It just died out of no where while riding.

I saw on another thread you had screws stripping on you. I second that you should expect to replace the hardware. sickbikeparts.com has a nice package with all the screws with allan heads. Definitely replace the hardware that holds on the chain tensioner. Get some good stuff at home depot. You have to make sure that tensioner is rock solid. The hardware they supply you with will strip and loosen over time.

 

[Zack01GC]

Well I got it running again today. Had to do some adjustments to the idle screw (still need to), and need to adjust the clutch. But were on the road!