hi everyone,

i finished my busa powered rush late last year, but have been having problems with the gearbox. when driving hard the change from 1st to 2nd can sometimes refuse to go in. at first i thought it might have been me not being positive enough with the gear selector, but still suffer with the problem even if i'm being careful. when poodling around i don't seem to struggle with it the same. as we've only got a couple of months to go i thought i'd better get it sorted ready for the sunshine. I have looked at obvious things like slack or problems with the linkage but all appears fine. i am going to have the motor out and split it on friday but was looking for advice on what the problem may be. i was thinking along the lines of selector forks - any ideas?

thanks

alex

how are you doing your upshift.

1.Is it pressure liht/moderate pressure on gearstick and backoff on the throttle and then straight back on.

2. backoff on the throttle and then change and back on.

3. cec style with the clutch.

Hi,

The selector forks do wear and they're not expensive so change them if in doubt.

The two selector shafts also bend and don't eventually go back to their original shape, TTS sell a far higher quality replacement pair for not a lot of money, speak to Richard at TTS, he can probably also supply the forks and gaskets you'll need.

Another thing you need to do is to shorten the arm that Dax sell that slides onto the gear selector, used to be a little piece of alloy. I cut mine in half or you can buy one from PowerTec which is shorter, without doing this there is too much movement in the rod system and not enough feel. Don't think this is expensive either.

[Edited on 31/1/07 by bike_power]

When did you last replace the oil in the engine/box.

Simplest things first

ATB

Simon

when it comes to gearchanges when pottering about generaly use the gearing same way as normal car. 1st to second generally the same, clutchless off moentarily off the power gear straight in no problems.

I am on the second lot of oil and i still havn't covered a thousand miles yet.

the bit that puzzles me is the fact that it is only when giving the motor a bit of a tough time that it happens. I really havn't had much use from the car so far as i lost last summer screwing around getting it tested.

i have actually been through the forums and about 4 pages in someone seems to have been suffering with the same problem but on an r1.

thanks for the tips, i have managed to get a copy of the suzuki service manual so will take my time pulling it apart and checking all the tolerances etc. i'll get a set of stronger bars etc to put in while i'm in there. I'm kind of crapping it as this will be the first time i've split the engine - should be interesting to set a feel for how the box works though.
I'll let you know how i get on

Alex

Hi the busa engine split is a easy one and straight forward but if you have any problems give me a ring ill talk you through it
cheers malc 07960011585

It could also be the dogs between first and second that are worn - if you're not sure, these are the lugs that key the gears together. This is a usual problem if the bike had spent most of its previous life on the back wheel....

Whilst you're in the box do have a check of these - the edges should be nice and square and not rounded off at all.

I've had exactly the same problems on a 'Busa.

It turned out to be the dogs on 5th and 6th and the selector fork that was associated with these gears.

The cause of the trouble was a shite quality gear change cable and the shaft that the selector forks ran on was not of the corrct surface finish and was causing them to bind, Scotchbrite sorted that. The tracks in the change barrels also benefitted from a little dressing with a diamond file.

It cost about £300 in bits as the one gear we replaced was an expensive double gear.

Thanks for the tips. oils out, coolant being dropped tonight - start pulling it all apart tomorrow am.

Alex

well i've managed to get it all stripped back without any problems!

i've had a good look at things and it appears that the single selector fork is quite badly worn around it's inner surface. It is also narrower than the others they are apx 4.9mm and that one is 4.8mm on the worn side. I am wondering if this has been caused by the bar it's on being bent as was suggested. certainly the guide it sits in is polished much more than the other two - as though there has been more friction on it.

The gearbox appears ok - the only thing that caught my eye was that sixth gear feels a little sloppy on the shaft - is this normal or should it be a firm fit with no loose feel to it?

the dogs appear to not be identical, some appear chamfered on the edges and others not - none look worn although this is difficult to say for sure. I think i will remove all, clean and check against the service manual.

could this worn finger be the problem?

i have posted picturs in my 'photos' section. If anyone can take a look and give me their opinion i would appreciate it.

cheers

alex

quote:

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Originally posted by busarush
could this worn finger be the problem?

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