B400 "lurch" in second gear

[zaptoman]

Took the bandit out for a spin earlier and the bike seems to lurch at several different points in second gear, but does this nowhere else. I'm guessing this isn't a false neutral b/c revs don't go up? The bike just seems to lose power than get it back in a snap. Whats going on?

[tacoman]

I would say its fuel related.  The particular vacuum level generated in second gear is probably not duplicated in another gear.  Try the usual diagnostics:  Check all vacuum lines for leaks or kinks, is the diaphragm damaged? plugs and filters ok?.  Carbs clean?  You may want to try some fuel additive if you have some minor varnich deposits in the carbs.

[Bob Holland]

If this is happened in 2nd gear only, under hard acceleration, then you have 2nd gear bad. The engageing dogs get rouned off and when you accelerate hard, they push the gear out, it skips, and then re-engages.
I have repaired a bunch of these on Suzukis and Kawas, and even one FJ 1200.

[zaptoman]

If the bike was actually coming out of gear, wouldn't the revs go up? The symptoms are like a sudden loss of power and then *snap* its back on. It takes all of about a half of a second.

[Bob Holland]

The last thing you want to do is split the case to fix 2nd gear, so try everthing else first. I went though this with a RF 900, I swore that it couldn't be the trans, I even bought a Dyna 2000 ignitition, went though the carbs a half doz. times, it was 2nd gear. When it pushes the dog out, it only skips to the next position, it goes out and back in so fast that it is just a slight hesitation. If it does it enought it will breaking the shift fork.