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baja clutchbell screw??

Old 04-11-2008, 12:46 PM
  #26  
Argess
 
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Default RE: baja clutchbell screw??

I'm having a hard time picturing this as I didn't pay enough attention last time I changed that screw, but:

1) Before you install the screw, can the pinion slide back and forth along the keyway in relation to the CB? If so, there will be positions of the pinion where there may be some shear exerted on the bolt. So, if there is some side-loading on the screw, and if this changes twice per revolution, fatigue can be expected due to the alternating loading of the pinion in single shear. Next time mine breaks, or I have the clutch apart, I'm going for the 5mm bolt.

2) Loc-washers really don't do much. By the time a bolt is loose enough that the lock-washer can help, it's also loose enough to fatigue as the pinion to CB can't be a perfect fit, and some wobble must occur. Since I will use loc-tite, I think I'll just put a flat washer there instead.

3) Mine broke twice. First time was from when the factory put it in, so can't comment on that. Next time was me forgetting to use loc-tite when I was upgrading the clutch spring. In-between those two times, it was used a lot and the bolt didn't break.
Old 04-11-2008, 12:52 PM
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TurtleRacing
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Default RE: baja clutchbell screw??

No, there should be no movement, the combination of the key and the bearings locate the pinion and bell. The screw's single purpose is to hold it together, that's it. Unfortunately, it's not doing it. Honestly, I think the 5mm is the BEST way to solve the problem.
Old 04-11-2008, 01:32 PM
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Dave ESPI
 
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Default RE: baja clutchbell screw??

I was having issues with the screw backing out, so I got a HPI pinion w/ heat sink, and a slightly longer screw and retaining washer, and it works perfectly now with a bit of red loctite on it hand tightened, but not torqued down really hard.

Oh, and I'm running the Vertigo cover and bell and stock gear set from HPI. No issues.

EDIT: I speeeal real goud.
Old 04-11-2008, 01:38 PM
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Lunar Wolf
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Default RE: baja clutchbell screw??

^^ Yep and you've been bashing hard enough for your nuts to fall of too!!!
Old 04-11-2008, 01:42 PM
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Dave ESPI
 
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Default RE: baja clutchbell screw??

ORIGINAL: Lunar Wolf

^^ Yep and you've been bashing hard enough for your nuts to fall off too!!!

Dude, my baja has like around 6-10 full tanks of gas through it......... and its is so far from a "shelf queen" it is hilarious to even think about such a notion anymore... LOL.

EDIT: Ah speeal reel goud yo.
Old 04-11-2008, 02:26 PM
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Argess
 
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Default RE: baja clutchbell screw??

Well.....curiosity getting the better of me, I decided to have a look. After all, I knew my stock CB was cracked where the two parts were fastened together, and I have this Integy one just sitting there, so........

The scoop is that the key-way is a very tight fit, plus I hadn't realized the outer bearing holds it together. But the fact is, the gear can wobble under load....back and forth along the keyway. Looks like it might be because of normal play in the two bearings. This cyclical loading and un-loading is minimal in a tight screw, but still there. So I conclude that it is fatigue causing the failure. This of course is maximized if the screw loosens, as in my case because I forgot to loc-tite it.

So I didn't do what I said I'd do......I didn't put in a 5mm bolt (and from the backside of the CB) with a loc-nut over the pinion. I just loc-tited the 4mm one in place and made sure it was good and tight. I want to see how long it lasts. "Then" I'll do the 5mm thing as I do agree....it's the best "fix".

By the way, I can't see the pinion expanding enough from heat to stretch the bolt to failure. Don't forget, the bolt elongates as well when it gets hot, plus the plastic carrier would totally deform if the heat got that high.

Hey....Mr. TurtleRacing Guy....here's a chance for some feedback. I am not impressed with the Integy CB. Although the built up CB appears stronger (heavy swaging vs. what looks like a ground-off weld on the HPI unit), the CB rotates noticeably untrue when you turn it by hand......very noticeably. Plus, the key needed to be de-burred a bit before it would fit in the pinion. In another post there was some talk of Aluminum CBs made by Turtle. If you also sell steel units .... that run true and have a better fit, you're my next stop for a CB purchase.

Edit....to that guy who made a question about my first post in this thread, I just checked and my stock HPI CB is drilled through, so the repair can be done as suggested.
Old 04-11-2008, 02:51 PM
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TurtleRacing
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Default RE: baja clutchbell screw??

Argess, I can tell you that my Steel Bells are billet, one piece and turned true. I do make alum bells also, they are one piece too but I don't recommend them for the daily basher, and honestly we've had very mixed results as far as wear goes with them. I really feel it depends completely on the individual situation. I run mine for a long time before they're done, some people wear them out faster. I have guys racing in Europe that swear by them because of the excelleration and they are willing to buy a bell more often to get it. But for a good, true, long lasting bell, my steel bell is it. Hope that helps.

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