4g t belt clutch trouble

hmiwb

hmiwb

New Member
I'm struggling with my first build and am having a time with the clutch on my 5/8 shaft HS. After the first couple of miles I found that the clutch would no longer release at idle. Today I finally took it apart and found that two of the three clutch bolts that hold the shoes had ripped out of the center hub and were rubbing against the clutch drum so of course it wouldn't release. Now does anyone have any idea what could have caused this? The threads were actually pulled off of the shoulder bolts. I've been reading everything I can about these transmissions and have never heard of anything like this happening. Any ideas?
Thanks!
 
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To me, that sounds totally like a factory thing. I can't think of anything in normal operation that would put that kind of stress on those bolts. I think I'd be sending some pictures of it to the vender and asking for a new clutch.

Speaking of that, do you have any pictures of the damage you could post.

Fred
 
This seems to be an almost common fault with the latest 4G's and that poorly designed clutch. I've read of several complaints regarding this clutch and it seems they are not being put together properly at the factory and the springs they are using are really to weak for the application. A tiny dab of lube on the alignment pins is in order too.

I'd ask for a new clutch as it's a new kit.....shouldn't be a problem.

dnut
 
Thank you for your responses as you've confirmed my suspicions that the bolts were likely stripped out at the factory. I guess friction held them together until the vibrations and centrifugal force helped things fly apart. Here are a few pictures (my first attempt at photo posting so here goes). The bolt heads did a number on the clutch bell too.

http://motorbicycling.com/attachmen...ent.php?attachmentid=45390&stc=1&d=1330142609
 

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Did you by any chance fire up the motor with the clutch keyed on the shaft but without the bell installed? That would probably do it! Either that or what Scotto said, or they just didn't torque them correctly at the factory and they loosened while riding... Sorry to hear about your problems. Were the threads pulled off all the way on the bolts or just near the ends. If it is just near the ends they probably just came loose. If the whole bolt had the threads ripped off...??
 
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There, I finally got the photos uploaded right. No, the bell was in place, in fact the whole bike was assembled before I first fired the engine. As I hope you can see from the pictures, the threads are stripped along almost the whole length of the bolt and they are also stripped out of the hub. I think it's just a case of over torquing them at the factory now that we've looked at the other possibilities. As a side note, that little HS motor started on the second pull and ran and idled great from the very beginning. It's an impressive little motor. Thanks guys for the help and comments. Now to see if bicycle-engines will warranty it for me.
 
I'm betting they will warranty it, no problem. The pics you have show clearly what happened so I'm thinking discussion about that should be minimum.

I have a 4G kit too from BE. No problems so far. It's been great.

Good luck with this, but I'm sure it will turn out fine.
 
Mine just blew out the clutch drum for the second time. It had been welded before, now it's pretty much shot lol
 
Thanks for all the information and support guys. I'll let you know how this turns out. During the short time my bicycle was running I managed a scorching 26 mph. It felt plenty fast to me so I'll remain a member of the 20 mph club for the foreseeable future. 49cc is max displacement for a motor bicycle in Missouri and 30 mph is the max speed. Since I'm the only motor bicycle I've seen in town I'll remain very legal until I see how the local constables in town react to it. :-)
 
Update: bicycle-engines.com is going to replace the clutch under warranty. Thank you bicycle-engines.com and to all of you on the forum for your input and responses.

Hello Bill,

Sorry to hear about the problem. That is really weird, I have never seen a clutch bolt have its threads pulled off like that. I would have to agree with you- that they were probably over-tightened at the factory. I have created a warranty invoice for you and the clutch and clutch bell should be shipped out to you today. You should receive an e-mail before 6PM mountain time regarding the tracking number of your package. Thank you for providing pictures in your e-mail, as it really helps us fix your problem in a timely manner.

Robert
Technician
bicycle-engines.com
1-800-514-8435
 
I figured that would happen. Robert and his cohorts at BE have been great to work with and very helpful with questions I have had, Kudos to Bicycle Engines.com!dance1
 
I second that fredgold52. They handled it quickly and well. I've been spinning wrenches most of my life, but I'm new to these motor-bicycles. I've learned a lot from this experience and I'm sure I still have a lot more to learn about these critters. The members of this forum have been very helpful and I really appreciate the advice and feedback. Thanks!
 
Yes! New clutch installed and is working like it is supposed to. Big Thank You to Bicycle-Engines.com for excellent warranty service!
 
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