killswitch & clutch

BikeGuyver · Jul 21, 2010

I'm waiting for the replacement clutch wheel that broke within 2 days of getting the bike running. In the meantime thought I'd post some pics (really bad quality) and ask some questions.

After I get the small clutch wheel, I'm going to find a good woodruff key that fits and I want to make sure it doesn't come out. Should I use locktite?

I think part of the reason my clutch wheel broke is I was stalling the motor because the killswitch wasn't working. Would that contribute to excessive torque on the clutch?

I had the green wire taped to the bike frame and the yellow wire going to the engine white wire. I don't want to splice the killswitch wires to the blue & black wires yet, I'm going to get my dad to help me with that. I believe that's the recommended way (splicing the wires, not the dad part

. So any ideas why it wasn't working?

And it flies! I went around the neighborhood park and it goes really fast, even on the grass.

The pics: I have the clutch cover off and the small bevel gear is missing (split in two).
It took me awhile to figure out how to do the handlebars. I had to get rid of the front derailer to install the engine, so I moved the right gripshift to the left side. At first I took off the front brake, but that was a bad idea, so now I have both brakes. Clutch is on the left also. Front tire is flat (have to repair a slow leak). And I have a part to secure the exhaust pipe to the frame that I haven't put on yet. .bf.

BikeGuyver · Jul 23, 2010

i got the new bevel wheel but it doesn't seem to want to fit on. i lubed up the shaft, and pounded the heck out of it with a wood block, but it's still sticking out about a 1/2 inch. i only saw one size on the bikeberry site. any suggestions? i figure if it's on so tight i don't even need the woodruff key, cuz it fell out as i was pounding the wheel in and i just left it out.

Goat Herder · Jul 23, 2010

Your gonna need that key! Take a slower approach get it all to line up gracefully. You can use the nut to seat it together at first. Then get the nut all the way tight by having the chain on and holding the rear wheel still. The hammer sounds scary! We are talking about the output sprocket on the motor?

I wold recommend getting your kill switch wired in its good for killing the motor in a panic. As for letting the clutch out at Idle to kill the motor I have done that hundreds of times with out a problem. Still more polite to the engine to use your kill switch.

Goat Herder · Jul 23, 2010

There could be two sizes of out put sprockets out there don't know.

corgi1 · Jul 23, 2010

Is the shaft tapered,,is it possible the small gear needs to be turned over?and you need the key in it

BikeGuyver · Jul 23, 2010

What nut to I use to seat it together? Not sure what you mean. corgi1: yeah, the shaft appears slightly tapered, however, I believe the threads on the small wheel need to be pointed outward, for the puller tool. So I'm pretty sure it's on correctly.

corgi1 · Jul 23, 2010

Ok ,that sounds right,might use the puller gently and see if there are any burs raised up from pounding it on and figure out why it is resisting and put the key in,,,,,check fit the key to the gear and the shaft,,,did the shaft get scared up when the old gear failed,,,,,and when you get it togeather remember the small thumb nail size blob of grease ,put it on the small gear teeth

Goat Herder · Jul 24, 2010

BikeGuyver said:
What nut to I use to seat it together?

The nut that holds the sprocket on originally. If everything is aligned perfectly you should be able to take a socket or wrench to that nut and do light taps with the palm off your hand.

BikeGuyver · Jul 25, 2010

corgi1 said:
Ok ,that sounds right,might use the puller gently and see if there are any burs raised up from pounding it on and figure out why it is resisting and put the key in,,,,,check fit the key to the gear and the shaft,,,did the shaft get scared up when the old gear failed,,,,,and when you get it togeather remember the small thumb nail size blob of grease ,put it on the small gear teeth

Pulled the gear off with the puller. Doesn't appear I mucked up the shaft or gear by all that pounding, thank goodness. Here are some pics of the assembly - The key fits perfectly in the new gear wheel (which looks like the same size as the old one, in fact I had trouble refitting the old gear on the shaft on too) but seems slightly too small for the shaft. I don't have any way to machine a larger key down.

I can only put the gear on a few mms before it gets tight. Still not sure how to fit on the gear

Since the key is smaller than the cavity, perhaps locktite and/or some sort of filler to ensure a tight fit of the key is in order . . . once I figure out how to get the wheel on. Thanks for the help guys

corgi1 · Jul 25, 2010

I don't have one of the pullers,ANYBODY know if it can be operated it reverse too press the gear back on,,,,Is the key too tall for the gear to slide on?,,,,,,You can use a (new)bastard file too machine the key if it is too tall

BikeGuyver · Jul 25, 2010

corgi1 said:
I don't have one of the pullers,ANYBODY know if it can be operated it reverse too press the gear back on,,,,Is the key too tall for the gear to slide on?,,,,,,You can use a (new)bastard file too machine the key if it is too tall

no, the puller works like this: bad ascii diagram following:

|\\\\\\\\\|
---|----> [=====
|\\\\\\\\\|

where arrow is the force pushing on the crankshaft, it pulls by pushing(!), so you can't reverse it. key is secondary problem (gear won't fit on even if key is out of place) i believe the key is correct size, though. after examining the original broken gear, the key slot is badly maimed. I think this is because key didn't seat properly on shaft and slipped out damaging gear. But you're right, I need to find some way to slip the gear on without pounding it. Don't see any defects on the shaft (besides the enlarged keyhole) so I believe the tapering is the problem with the fit. I do have files, which I lightly went around the shaft, but didn't feel or remove anything.

Bikeguy Joe · Jul 25, 2010

Maybe the original gear split because the shaft is not the right size and THEY pounded it on when assembling the engine?

corgi1 · Jul 25, 2010

do you have a BRASS hammer ,or a block of brass that fits over the outside edges if the gear(Harbor Freight,$8-$10 I think),use the brass hammer as a punch and tap it w/a reg.hammer,possibly the wood block has too much give (spring)

corgi1 · Jul 25, 2010

that is a grave and real possibility

corgi1 · Jul 25, 2010

Norm ,how tight are these susposed to be,I would think a press fit and the key is only a safty beacause the bolt that holds it to the shaft ,I thought has a large flat screwdriver slot?

BikeGuyver · Jul 28, 2010

no luck . haven't tried a brass punch yet. I'm taking it over to my dad's place tomorrow hopefully he can help. My guess now is, freeze the key in with some goop, wait 24 hrs, hopefully key ends up straight so I can slide the bevel wheel over it, and pound it on... last time I had it on it was sticking out and I think the key slid out. Too bad my dad lives 5 miles away and I have to pedal

-- leaving town on the 6th so that's what I bought this bike for... planning a 55 mile trip... i wish i can get it running by then.. that's the plan

GearNut · Jul 28, 2010

How well will the gear fit onto the shaft without the key?
Don't get me wrong, you HAVE to use the key for it to work right.
I am just wondering how well the gear is matched to the shaft.
I fit fits well enough without the key you may have to custom fit the key to the gear and shaft. A nice snug fit is best, not sloppy loose or gear splitting tight.
Considering how these engines are assembled it would not surprise me if they have a bin full of gears and they just keep trying different gears on each engine until one fits well.
The way I see it, each engine is essentially a custom build and I bet they would have to be considering the poor quality control on each and every part that they are made up from.

BikeGuyver · Jul 31, 2010

Took it down to the shop & the guy said to try torching the piece to heat it up and slide it on. Whupped out the old man's blowtorch and blasted the gear. Didn't quite slip on but I got it further than before. Key is held in place with some locking goop. It still needs to go another 1/2 inch I'd say, to get a better hold on the key.

Allen_Wrench · Jul 31, 2010

BikeGuyver said:
Took it down to the shop & the guy said to try torching the piece to heat it up and slide it on. Whupped out the old man's blowtorch and blasted the gear. Didn't quite slip on but I got it further than before. Key is held in place with some locking goop. It still needs to go another 1/2 inch I'd say, to get a better hold on the key.

(I know I run the risk of somebody saying "Well, DUH!", but here goes) There is something not right here, and until you discover EXACTLY what it is, well, I would feel obligated to pray for you if you decided to run it as is. I thought, when I started typing, that after looking at the picture I would soon have something more constructive to say. But I don't. You've tried, but it doesn't fit. It would seem to just be the wrong size. I know that's lame, I wish I could have been more help. Sorry. scratg

corgi1 · Jul 31, 2010

Try again w/the heat,and maybe dry ice on the shaft for awhile befor heating the ring and droping it on,ir measure w/inside and outside mic's and see if it is even reasonable too try with out machining the gear

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