Kawi2strokes.com Forum

Hi.
I have lately reassemblied my gear, and all gears are undercutted. Before I took it apart, the bike jumped out of 2. and 3. gear quite often.
After the assembly, this issue is solved completely.

BUT:
A new problem has come. First gear are jumping under load. Not completely out as the 2. and 3. gear did previously, but more like of a chain jumping over 1 teeth if you know what I mean. Experienced this a couple of times, and then I have not used 1.gear anymore. Rest of the gears are OK.

What may have gone wrong?

Is this a shim problem?

The 1. gear was OK a vouple of days, and I easily did some powerwheelies without this happening.


Hope for help....

A couple of pictures of the tranny after shimming, ready to be locked together in the cases. Not that they show much, but maybe they show something else which is bad?


Jorgen

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72 H2, 72 H1B, 74 H2, 74 H2 Cafê Racer, 71 F8 Bison

I have had the same thing with undercut gears..although only rarely. It is exactly as you describe and the first time it happened I thought my front sprocket was coming off. I came to notice it only happens when there is a less than positive engagement of 1st gear. I think the gear has not completely engaged so it spins a little and then locks in. I am conscious when grabbing first gear, to make sure it is a crisp "lock" in -- if not, find neutral and do it again.

The gear with the chunks out of the teeth appears to have a large radius on the dog.
Even with the undercut, this could be your issue if not engaged properly.
Are your shift forks in good shape?

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http://kawatriple.com/wtf/

Thank's guys. I'm gonna try have 3-4000 rpm and then "throw" it into first gear and see if it holds. There are some visible marks on the shifters, and partly some blueish. But they are the same shifters as prior to the overhauling, and they worked well back then.

I will have a closer look on the dogs you mention Walms, if I must take the damn motor apart.

Also have other issues with my porting (now have 79 rwhp with higgsy pipes at a little less than 3/4 throttle at 7000, and she starts coffing a lot) Aim for 100 with blow down about 32 degrees, (now it's 39 due to heavy ex. porting) Jolly Moto pipes and perhaps other carbs than the chinese junk staying on right now.

So have to take apart whole top end anyway, that makes it easier to take the cases out of the frame and split for inspection.

Here's a picture of the shifters, taken when I disassemblied the motor. Bad quality.........

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72 H2, 72 H1B, 74 H2, 74 H2 Cafê Racer, 71 F8 Bison

I see a lot of rounded dogs on the gears, if the gearbox kicks out of gear, you can very easily bend a shift fork, just from the pictures, it looks like you could use some new gears.

Gearboxes are not magic, put everything in the top case half, shift from gear to gear and look to see how well the dogs are engaging. Push each gear to the limit of its movement and see if there is any noise or interference.

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Using a poorly conceived idea along with bad mechanical practice is not an upgrade but rather a recipe for disaster.

To check the shift forks, just measure the side clearance between fork and gear... From memory I believe it should be .004"- .010" if more than that, you should have them repaired or replaced. Double check the proper clearance though.

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http://kawatriple.com/wtf/

I will.
Thank's for the specs

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72 H2, 72 H1B, 74 H2, 74 H2 Cafê Racer, 71 F8 Bison

Those rounded dogs, look to be about 20-30% of the dog, and they usually don't deep engage anyway. So with any play or bad shimming, I can see the gears slipping out.......

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Would you run gears with chunks missing like that - some bad history there...?? (Am I missing something?)

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"One day, your life will flash before your eyes. Make sure it's worth watching." : anon.

From the looks in the pic, I would say a new gear/gears is/are needed. The condition of the dogs and the teeth are far from decent.

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