need 44t sprocket to fit coaster brake cruiser

Hey Folks,

I'm working on my first build, putting a grubee 66cc on a Retro cruiser. So far, nothing has fit. I managed to get the engine mounted securely though, using some creative jury rigging. Now I am on to the sprocket and chain assembly. As the assembly instructions predicted, the center hole for the 44 tooth rear sprocket is too small (36.9 mm diameter) for my coaster brake hub (which is about 40 mm diameter). The instructions recommend taking it to a machinist with a lathe and enlarging the hole. The posts I've seen here have indicated they just enlarged the hole themselves (e.g., using a Dremel). Jeez, but there's got to be an easier way.

Surely, I can buy a 44 tooth sprocket that will fit my coaster-brake cruiser, can't I? If not too expensive, I'd rather just buy a new sprocket rather than try to enlarge the hole on the one that came with the kit.

Any suggestions?

Thanks,

Steve

 

[fetor56]

I can't imagine anyone saying to use a dremel....if they did they sure like creating work for themselves.
I used this bit with a drill press & used it like a lathe...worked fine but if u don't have a drill press it's going to take considerably longer with just a drill.
http://cgi.ebay.com.au/Tungsten-Car...ash=item3ef7f64349&_trksid=p4634.c0.m14.l1262

Ideally a machine shop job but since i'm cheap i've found it's never an ideal world.

 

[Hawaii_Ed]

I used a Dremel on my first build, the metal is pretty soft, took me 20 mins or so...There are some custom sprocket vendors around, and some nice clam shell adapters too.

 

[Turtle Tedd]

Check out CREATIVE ENGINEERING...sprockets and adapters (among other goodies) machined to close tolarences to fit different individule hubs...they do not attach to the spokes ..they run perfectly true to the axis of the wheel hub.

 

[Porkchop]

I've seen that where they recommend to use a Dremel tool. Don't know if you've ever used one or not, but from my experience, I think they're a great tool, however, the grinding stones and other attachments don't last very long at all. To take off 3.1mm, you'ld probably pay more in grinding bits/stones that you would a machinist, which would be way more accurate.

 

[WhizBangAndy]

Go with a local machinist. Cost me $10 bucks and he did it while I waited. Nice round hole perfectly centered. Cant get that at home unless you have a metal lathe with a really big chuck on it. Or you can buy a 9 hole sprocket for like $20 from one of our fine vendors on here. Good Luck!

 

[jbrewer]

problem after problem

Thanks to all repliers

It looks a machinist or perhaps a sprocket from Creative Engineering is going to be the solution.

Just for kicks, I took off the dust cover and put on the sprocket, just to see how things would work. Unfortunately, and has been posted previously, the coaster brake arm doesn't clear the sprocket bolts, even after trimming the ends with a bolt cutter.

The solution offered by almost previous posters is "bend the arm".

Hmmm. So far, I'm batting a thousand. Not a single thing is going as planned. My guess is that I'll run into problems with the clutch, carb, and exhaust, given my luck. I like the bike and don't want to ruin it. I've decided to remove the engine and find another bike (cheap, preferably) that will receive this engine with as few modifications as possible.

Any suggestions?

Steve

 

[Hawaii_Ed]

Mounting the rear sprocket is really the biggest challenge. I also had to bend brake arm out a little, was not too bad at all. No need to give up on the bike if you like it, just take the whole thing into a machine ship and get some help. They can easily bend the brake arm with a vise for ya too!

 

[WhizBangAndy]

A rear coaster brake is a less than ideal braking system with these. They tend to lock up and put you on the road in a panic braking situation. I know this from personal experience. Not to confuse or complicate your build up anymore than it is.

 

[jbrewer]

Hey WhizBangAndy,

thanks for you comment. The more i think about this, the more i think it is bad idea to use a coaster brake to stop a 66cc gas engine. I really like the bike, and I don't want to convert it to v-brakes or disc brakes. I'm starting to think it's better to use a bike with suitable brakes to begin with. I've already ruined the rear wheel trying to do this and have to get a new one.

Steve