Author Topic: jumping out of 1st gear (Read 2874 times)

eddievtwin · « **on:** June 25, 2007, 01:54:35 PM »

Hi guys , got a problem on my suzuki gsxr 400 gk76a, when hot it jumps out of first gear then engages, all the other gears work fine any one had this happen before , something simple ( i should be so lucky ) any one had any gearbox problems ??

Thanks Eddie

Bartjan · « **Reply #1 on:** June 25, 2007, 04:13:02 PM »

do you mean it jumps in neutral and you have to put it in gear again? or do you mean it jumps to neutral and jumps back to the 1st gear?

if it is the 1st problem, then most likely the holes in the sprocket of the 1st gear are rounded.
remove the gearbox and sharpen the corners up again so its not round anymore and it will probably fix the problem

if it is the 2nd problem, then i wouldnt have a clue

pmackie · « **Reply #2 on:** June 25, 2007, 06:26:30 PM »

There are really only two reasons a transmission jumps out of gear:

1. As Bartjan suggested, the "Dogs" on the gear are rounded off, stopping the driving and driven gears to mesh completely, or

2. The shift fork is bent slightly, not letting the gears engage completely.

Either problem tends to cause the 2nd problem to occur, over time.

Usually means a tear down and repair.

The only other thing you can do is to shift carfully/completely and ensure that 1st gear is completely engaged prior to putting on the power, but this problem will likely only get worse as time goes on.

eddievtwin · « **Reply #3 on:** June 26, 2007, 10:46:56 AM »

oh well looks like another tear down jobbie

cheers guys

gsxr400 racer · « **Reply #4 on:** June 26, 2007, 12:56:46 PM »

you can replace the shift forks on these motors without tearing the whole motor apart just drop the oil pan and take the clutch cover off and clutch assembly and basket out

eddievtwin · « **Reply #5 on:** June 29, 2007, 01:36:56 PM »

well she's fixed and working again , there is a dowel in the lower crankcase which holds the end bearing cap on the end of the gear shaft which i hadnt got spot on . So it had forced it into the casing when i tightened up the crankcase halves , so allowing the shaft to have to much end float, allowing the gear to fall out of mesh . So i pushed the dowel through with a hammer and punch ( it had allready knocked a hole through ) then replaced it and loctited it into place . Then made sure it was in place properly this time when tightening the cases together this time. Problem gone , Phew !!!

Eddie