Ripped up clutch shaft bar

GoldenMotor.com

f412707

New Member
Aug 27, 2011
10
0
0
Seattle
I have been riding on this engine for a few months non stop now. this last tank fill up i ran out of gas in the middle of town and had to eyeball the mixture. well two days later i came to a red light. i pulled up to a hyabussa and decided to show him up. I carefully watched the opposing lite to turn yellow, so i could get a jump on him. the light went yellow. 3... 2... Wham go... I went no where. my engine went full rpm, my clutch was out and i was a sitting duck. needless to say the hyabussa burnt me. so i peddled all the way home. i get home remove my clutch case and find that the sprocket just fell right off. Some how i ate all the threads on the clutch shaft right up and there are like four very thing washers that were loose and the clutch case itself was eaten up. i think my chain was to tight for starters. but before i go and buy a new shaft, i need to know how to fix this right, and what made this all happen. In the beginning this bike was to save money on commuting. but now my girlfriend is calling it a money pit, cause i keep buying replacement parts. I don't want my journey with my motorbike to end. please help so i can continue racing and getting to work on time. thanks - Cory up in Mukilteo seattle area. oh and if anyone knows of a motorbike mechanic in the seattle area let me know. xct2
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
There's an old saying among racers; "If you're gonna race it, you're gonna break it".

It sounds like you might be a bit rough on that little Chinese engine. Soft pedal starts and allowing things to get up to speed gradually would help keep you from breaking things. They were just never designed for hard clutch drops off the line or even long range WOT conditions.
Replace what you broke then give that little 2 stroker a break and treat it a tad more gently. With proper care the little HTs can provide many many miles of malfunction free riding.
Tom
 

f412707

New Member
Aug 27, 2011
10
0
0
Seattle
yea i totally agree with you on that reply. Not going wot all the time is a bit hard for me, as im always in a hurry. do you have any idea with uhhhhh. the sequence of what might have happened or if it was truly just me dropping the hammer to hard?
 

wheelbender6

Well-Known Member
Sep 4, 2008
4,059
221
63
TX
How could you disgrace all of us by being out accelerated by a 'busa? A 'busa engine is only 20 times the size of a bicycle assist motor.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
It's always hard to accurately diagnose a failure without actually seeing and examining the failed parts. The force applied to the drive components when a clutch is engaged from a dead stop can be a lot; probably much more than they were ever designed to take.
Then there's always the possibility that you had a defective or substandard part, sprocket, shaft key or keyway, that might or might not have failed eventually even with normal riding. Nevertheless you can't argue that hard starts probably contributed to the failure.
Keep in mind that proper chain tension and alignment are two of the most important aspects of a motorized bicycle and if not maintained can cause a lot of problems. We suggest 1/2 to 3/4" slack in the chain and the chain path alignment be as close to perfect as possible.
Good luck and let us know how the repairs work out for you.
Tom
 

f412707

New Member
Aug 27, 2011
10
0
0
Seattle
so yeah, im gonna try and get some pics up for you guys to look at and see if you can diagnose my problem. other then that one more lesson learned. as far as aligning the rear sprocket to the front do you have any tips. and when i sent a pic of these parts maybe you can tell me what they are as well. thanks how do i post photos? well i have the pics on my profile.
 
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f412707

New Member
Aug 27, 2011
10
0
0
Seattle
k go to the profile of f412707 and i have an album of what happened . there iphone pics so they kinda suck. i cant figure out how to post them on here though.
 

rustycase

Gutter Rider
May 26, 2011
2,746
5
0
Left coast
Well I suppose next time yah race a haybuser you both start w 2 ltrs and go for distance???

...Maybe stick that sprocket on there where it should be and have a welder strike an arc on it so you can run around town until the new parts arrive?

Good luck
rc
 

DuctTapedGoat

Active Member
Dec 20, 2010
1,179
10
38
38
Nampa Idaho
Unless you have a replacement, don't.

Just get an oversized woodruff key, dremel out a groove for it and drop your sprocket gear back on.
 

retromike3

New Member
Jan 9, 2009
148
0
0
Beaverton OR
I had a similar problem on my bike a few months ago. I went down to the hardware store and got a chunk of key stock and then cut and filed a new key. its worked (nock wood) well since then.


mike
 

f412707

New Member
Aug 27, 2011
10
0
0
Seattle
i have no clue what you guys mean by filled up a new key. what the **** does a key have to do with my prob. any photos of your guys fix ideas
 

retromike3

New Member
Jan 9, 2009
148
0
0
Beaverton OR
Sorry it took so long to get back to you. A keyway Is a piece of steel that sits in a groove in the drive shaft and a corresponding groove in the cog that is on the shaft. Most of the force of the engine is driven through that keyway. if its just the tapered fit the cog will just spin in place.

What happened to mine was that not only did it spin in place but it loosened up the nut that held the whole thing together.

mike
 

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