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Help! I Lost 3Rd Gear


luigi

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The aftermarket shift star, isn't better it has milder detents, that makes it seem better, that's all. If it doesn't hold the shift lever in its detent(WELL) then yes it can do damage. Hard to say what happened to yours, damage like that can happen in offroad bikes, although Ive never had a gear fail myself, other than in the only used motorcycle I ever owned. There have been periods of time where certain mc models, had weak gears and broke, and normally they changed to a gear with a better hardening process. I recall back in 79 (I think it was) one of the magazine test blew up a Cr125 tranny, I also recall in the 90's they blew a Yz125 first gear set. Course Honda over time built some of the strongest trannies made In the offroad world. Suzuki used to be a high wear tranny wear motor with lock ups ect.

Id say a defective marginal gear in your case, and may have been mostly broke when you bought it. But on the vfr as mentioned broken gear are rare. I still have original clutch at well over 100,000 ,miles and my bike is in hammer mode extremely often. But I don't pound my tranny , I treat it nicely.

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In my experience the shift star makes for more positive shifts; the detente spring is stiffer than stock so the shift drum is more positively turned to fully engage the dogs. There's less chance of the dogs being only partially engaged so I would have thought less chance of damaging the gearbox.

Its not obvious what caused the failure in Luigi's gearbox but one possibility is shift fork flex during missed shifts where the gear dogs back out and bend the forks. Do that enough times and the forks will snap, then could jam the gears and cause the breakage.

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Sometimes you eat the bear, and sometimes the bear eats you. :blink:

Or something like that.

Ciao.

I know.... :blush:

Ciao.

I appreciate that it's apparently rare, but MBrane had the very same misfortune, hence my concern.

Hi

I don't think existing a real reason for your concern; just two broken gears in all VFRD members don't represents an high percentage, No?

Ciao, Luigi.

...to sloppy shifting that's where it will likely fail first. The dog on the upper L looks like it's been floating around in there for a while. Once one of 'em breaks it's just a matter of time until the others fail.

HiMBrane.

Please, can you explain me what do you means with upper L? Can you show me in the pics?

Thank you.

Ciao, Luigi.

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HiMBrane.

Please, can you explain me what do you means with upper L? Can you show me in the pics?

Thank you.

Ciao, Luigi.

Upper left in the picture. It's the one with the most dents in it.

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  • 7 months later...
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Hi to all.

Finally i've opened the engine with broken gear causing 3rd gear malfunction.

As is possible to see from pictures Mbrane has definitively won his bet, this is what i've found inside the engine once crankcase opened:

gallery_8326_7434_102573.jpg

Additionally the Left fork driving the gear is broken:

med_gallery_8326_7434_189553.jpg

Maybe is not visible in pictures, but i've noticed that the gear have dark color, as annealing.

Now the engine is opened and i'm thinkin' about to make some work to increase performance, but is another story to tell.

Ciao, Luigi.

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