Bimota Forum

[375NE]

If I accelerate hard in second gear it feels like the chain slips a bit, only for a second, but very disconcerting. It's not the chain slipping so I'm guessing a gear problem. Does anyone know if this is common behaviour, and how do I fix it?

[Jonny B Bad]

I remember pineapple chunks from when I was a kid, but I guess your problem is probably something different You don't mention which model you're on. How many miles has it done and is it still on the original chain? If it's a 6 or 6r on the original chain, change it before it breaks on you. If you're sure that's not the problem and again assuming you're on a 6 or 6r, gearboxes are pretty robust. Are you aware of the bike's history and whether it has been subject to the attentions of a ham-fisted oaf?
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What, Jonny's gone!

[Evilchicken0]

Check the front sprocket has the retaining bolt in the middle.
Check the small sidestand return spring hasn't broken - the stand drops triggering the cut out switch for a second
Otherwise suspect the gear box - it might be better to see if there's a dyno near you to replicate this.
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Don't read everything you believe

[SB8R Tuner]

That's a common characteristic of a bent shift fork and the engagement dogs rounded off and possibly the shift drum if you don't catch it soon enough. I could do the water cooled 1100 engines in my sleep, as many trans jobs I've done!!

If the gears aren't too bad, I would recommend having them race undercut. They come with very little undercut from the factory but a race cut has more of an angle to prevent disengagement under hard acceleration.
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Bimota SB8R
Bimota V-Due
Bimota SB8R
Suzuki 1988 GSXR-750
Suzuki 1989 GSXR-750R

[Hursty]

That's not sounding so flash Hamish

Hope you can get it sorted before our summer kicks in
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Hursty from kiwi land

[375NE]

Yeah, it's all sounding a bit expensive and complicated. maybe I'll tootle around like a granny for the summer..yes its a SB6 mk1. I am, however, grafting some 996 forks onto my laverda to compliment new race carbs and new ignition/alternator....so that, if finished, might be my toy this summer as it's too expensive to register 2 bikes!

Pineapple chunks are awesome...tho when I managed to get some in England they were not well liked. Neither were Jafas...strange folk those northeners....

[375NE]

SB8R Tuner, are there any specs to define a wornout 2nd gear or is it just a visual guess? Can the existing gear be undercut and reused or is a new one advisable regardless of wear on existing gear. And is undercutting a known amount or are there varying degrees of undercutting?
I'm about to embark on opening gearbox for first time. A bike mechanic has advised to TIG 2nd gear into place once fixed but no GSXR forum has EVER mentioned that so it may be a bit of overkill? or for drag racing? Does that need to be done as I'm not keen to ruin a shaft like that.
cheers
H

[SB8R Tuner]

It is just visual. When you look at the engagement dogs, you will notice that the edges are rounded off when they should have a sharp edge. I have always reused the gears when I have them undercut. The only time I have replaced a gear is when one of the teeth have broken off or was bent. As far as the angle of the undercut, yes their are different degrees you can use. I'm not sure of the angles but I have always stated what I using the transmission for when I send them to be undercut, ie..road race or drag race. I have NEVER welded a gear to the shaft, and would suggest you not listening to that mechanic!!
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Bimota SB8R
Bimota V-Due
Bimota SB8R
Suzuki 1988 GSXR-750
Suzuki 1989 GSXR-750R

[375NE]

Awesome, thanks for that info. I'll let you know how I get on.