Engine drive sprocket stuck

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VTHokie

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Dec 18, 2012
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I searched the database and couldn't find exactly what I was looking for:

I'm building my first kit and I'm to the point of attaching the drive chain to the engine drive sprocket. Problem is, it was EXTREMELY resistant when I first started, so I removed the 3 screw-side plate, and managed to get the chain around the teeth - then I tried pulling the short end of the chain, now secured around the drive sprocket, and could barely get 3 more inches to pull through. Then the whole thing stopped completely. The drive sprocket is stopped completely, and no matter how hard I pull on that chain, the drive sprocket won't budge. I'm scared to try anything harder because I don't wanna break it. Please let me know if anybody's had similar issues / how to resolve this thing. The video showed it going through a lot easier :/

Thanks!
 
crassius

crassius

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Sep 30, 2012
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open the clutch side and remove the pressure plate while working on the chain - you can put it back & adjust the clutch later when your chain is running true (watch to be sure you don't lose any on the little clutch pads if they fall out)
 
2door

2door

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Sep 15, 2008
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crassius said:
open the clutch side and remove the pressure plate while working on the chain - you can put it back & adjust the clutch later when your chain is running true (watch to be sure you don't lose any on the little clutch pads if they fall out)
Click to expand...
No, no, no! Do not disassemble the clutch!!!!!!! Darn it. Why suggest to a newbie to start messing with the clutch?

To VTHokie, Remove the spark plug. The engine will turn easily with it removed.
With the sprocket cover/clutch mechanism removed the clutch is engaged. That's why the sprocket is hard to turn. You can wedge a screwdriver between the sprocket teeth and the engine case to help rotate it but take the spark plug out first. Once everything is assembled, chain on and clutch cable installed and properly adjusted the sprocket will turn with the rear wheel.

Be careful and don't loose any parts. In the center of the sprocket is a steel pin which protrudes and behind that pin is a ball bearing. These parts should be lubricated with a good grade bearing grease before final assembly.
Good luck and ask here if you have any problems.

Tom
 
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VTHokie

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Dec 18, 2012
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The spark plug came disassembled and I'd read that this caused some resistance, so I ended up removing the clutch plate and center screw, then I used a wrench to turn the smaller sprocket, which seemed to free up the engine drive socket. I'm sure I'll have a whole boat load of questions on the clutch when I get to that, but right now I'm stuck at a crucial part - the drive chain rubs my tire. Currently the rear drive sprocket is set up in this order:

Sprocket - Spokes - Rubber Pad - Rear metal backing

If I add a spacer in there to bring the sprocket out a bit would that help? Such as:

Sprocket - Rubber Pad - Spokes - Rubber Pad - Rear metal backing

Sorry to change the topic of the thread! Any help would be greatly appreciated
 
crassius

crassius

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Sep 30, 2012
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the reason to suggest the clutch was to be sure the engine wasn't locked up

Sprocket - Rubber Pad - Spokes - Rubber Pad - Rear metal backing is the best way, since a missing rubber pad can cause the spokes to wear & break when they rub against the metal sprocket.

NOTE: tightening the sprocket can sometimes pull so hard on the spokes that your wheel will end up with the tire dished a bit toward the chain - tightening the spokes on the other side will pull the tire back away from the chain

If you have big, balloon tires, you will want to try the sprocket with the teeth outside (assuming it isn't a flat sprocket).
 
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VTHokie

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Dec 18, 2012
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Thanks so much for the help. I have the sprocket with groove outward to allow the teeth better tire clearance, but still have a problem with rubbing on the drive chain. I'm assuming now that it's a tightening issue as you've suggested. I'm going to redo the rear sprocket assembly and tighten from the spokes-side per your instructions, and hopefully that will clear it up a bit.
Is it possible I could re-mount the engine to give it a better approach?

I also realized the dang kit is missing the pulley bearing wheel. The mount is there for it, just no pulley wheel. And the mount itself is nothing to brag about - it seems to torque inward which would dis-align the drive chain if it were working properly to begin with.

I'm so exhausted- I've tried just about everything I can think of and I just can't seem to get this bike together. I'd be embarrassed to admit how long I've actually spent messing with it, so I won't, but suffice it to say, you guys could have built 10 bikes by this point, and I still haven't figured this one out.
 
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GearNut

GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
Bummer on the missing tensioner wheel!
Don't beat yourself up on the time you have spent so far building the kit.
The advertisements might say a couple of hours, but that is a pipe dream. Especially for a first timer.
A well installed kit for a first timer could take a few days, depending on what all needs to be modified or custom crafted.

The engine locates it self in the frame cradle. You can fiddle with the mounts to mount them higher or lower, but moving them left or right is impossible unless you can fabricate your own mount blocks.

Here is a non inclusive but darned good primer on mounting an engine:
http://motorbicycling.com/showthread.php?t=20782
 
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crassius

crassius

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Sep 30, 2012
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VTHokie said:
I'm assuming now that it's a tightening issue as you've suggested. I'm going to redo the rear sprocket assembly and tighten from the spokes-side per your instructions, and hopefully that will clear it up a bit.
Is it possible I could re-mount the engine to give it a better approach?
Click to expand...
I meant that if after mounting the sprocket with both rubbers, if the chain still rubbed the tire, then tighten the spokes on the OTHER side of the wheel (where the pedal chain is) - this will pull the tire away from the motor chain.

The engine must be centered in the frame by the curve of the motor mounts, don't try to change that.
 
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VTHokie

New Member
Dec 18, 2012
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Virginia
Ah ok, I see what you're saying. I will certainly try this tomorrow morning when I get back to it, and hopefully have good news to report tomorrow afternoon. I'll post pictures if it continues to rub the drive chain.

One other question: can I load the side with the drive sprocket with more washers to bring it out or will this have adverse results?

On another note, I got a speeding ticket on the way home from working on the bike! (I'm building it at a friend's garage) An early x-mas present. Another reason why I need to be riding the motorized bicycle! .xx.
 
crassius

crassius

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Sep 30, 2012
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if you go out too far, you'll rub the chain on your frame - last resort would be skinnier tires
 
KCvale

KCvale

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Feb 28, 2010
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Phoenix,AZ
It really REALLY helps if you state what exact motor kit you are using, and the exact bike make and model. I have a pretty good idea from your experience so far but I'll just leave it at that.
 
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