66/80CC Sprocket problem

[fatdaddy]

I've had the same promlem with chains not fitting that SHOULD fit. Changing the drive gear usually works for me. Luck has it that I have a few fubar'd bottom ends with good drive sprockets. Just chalk up another one to fine Chinese quality control.LOL
fatdaddy.

 

[mapbike]

I've had the same promlem with chains not fitting that SHOULD fit. Changing the drive gear usually works for me. Luck has it that I have a few fubar'd bottom ends with good drive sprockets. Just chalk up another one to fine Chinese quality control.LOL
fatdaddy.

amen to that....

 

[YesImLDS]

Something that I think is overlooked with these cranbrooks is sometimes the sprocket doesn't fit over the coaster brake hub and needs grinded out so you don't have other problems with the chain as well. With my 36T and 32T I have had to do this to make sure I don't have a tight and slack chain problem. It could be that in one position it's overly tight causing these problems while where you set the chain tensioner it was just right.

Quality control is another subject! Ha! If you wanted to try another 44T sprocket I have two and would be willing to give one up for just shipping if you wanted to try and see if it's the sprockets fault.

 

[The-Dullahan]

I've gathered a number of parts for this build, including a better tensioner than the ones that seem to come in the kits, specifically for that reason. Even the U-Bolts for the mounts I've seen online for mounting to a wider frame (the Chinese ones) look flimsy and unusually thin, so I've avoided that.

As for the brake coaster, I removed that and the bike presently has friction brakes. I intend to convert it to disc brakes, but first I want the engine sorted out. As for the rear sprocket not aligning, I didn't like the way that most people seem to mount their rear sprockets (with a system that clamps the rear sprocket to the rear wheel spokes, as per what apparently comes with the "kits" online) because it seemed to be a very flawed design. It is not only unsafe (especially with the Cranbrook's 14 gauge spokes) but it puts unnecessary stress on the spokes and allows for the rear sprocket to vibrate as well as move, causing wobble and lastly, it offers little to no means of adjusting the alignment of the rear sprocket. Instead, I contacted B&S Machine Tool (At http://www.bsmachinetool.com/ ) and placed an order for an adapter that clamps around to the rear hub and holds a machined rear 36 tooth sprocket in place, similar to this one:

YesImLDS, I appreciate your offer, but even before my first post, I confirmed that the rear sprocket hasn't a thing to do with it. Even threading the chain through the engine's sprocket by hand, without attaching to the rear sprocket, it has the problem. It's definitely the sprocket on the engine. Just waiting for the tool to show up now, as to remove it... :/

 

[YesImLDS]

You got a good idea going for ya! Hopefully it works out easily!

 

[The-Dullahan]

Okay, so the tool arrived today. Switched the sprockets and all is well. As I said, I couldn't get the greatest photo of the sprocket while it was on the engine, but here's the sprocket that the chain did not fit:

But after removing it and comparing it side-by-side with the sprocket that was on my parts engine (which fit the chain perfectly) we can see the obvious differences in size. (Parts Engine Sprocket on left, current engine sprocket on right)

But everything bolts up now and it's on to putting the fuel line and throttle on. (then comes wiring my electronics and getting it registered)

 

[KCvale]

Pretty cool, looks like you have it geared for Enduro racing ;-}

 

[mapbike]

Nice bike, looks like the original sproket is very thick like it would work great with #41 chian.

I 'll bet you can go a very long ways between gas stations with that tank... I like it.

 

[The-Dullahan]

Yeah, we'll see. Fuel Economy has never meant much to me, given my 5-7 MPG on high octane in my daily driver. The way I see it, anything I ever buy will always feel like an economy car by comparison.

I've been working from nonstop (literally) these last few days, but I think I'll find the time to get back to work on the bike tomorrow. Needs to be wired up, tested and then the electrical parts have to be finished and reinstalled before registration, but I'm feeling like most of the work is done at this point.

Thanks guys, for the compliments and the help.