I think it's my shift star...

Does it stay in "neutral" until you shift again or does it just hang for a second or two?

Have you checked the clutch springs?

 

sounds to me like you need to make sure you have some slack in your clutch cable.

if that's adjusted properly, it sounds like you'll need a new clutch.



can you slam the gas and have it slip like that?

 

Well if the problem you're describing isn't the clutch, I can't see how it would hurt to try the fix. I think I'd opt for trying to replace that tension arm spring first though. Sounds like it's probably lack of tension on the gear, and not the gear itself at fault.

 

Hey man, i had a problem on my kx500. the damn thing would NOT shift into 3rd gear. turned out that the shift arm was bent and cracked. the bent part was hitting other stuff, preventing an upshift. that doesn't sound like YOUR problem, but another thing i found in mine was that the spring that automatically returns the shifter back to the between gears position was bent to shit. Anyways, that could be a problem.......

 

Your shift star needs to have positive detents in it or the gears will walk on the shafts. Do not modify the shape of them. If you are looking for smoother shifting, Highly polishing the detent arm and the star helps. Most of the time the real issues are with the actual ratchet not the star.

The engineers are smarter than the internet. If the bike does not shift properly, it is probably because of another issue not your shift detent.

FYI they all look like that for the most part. Most false neutrals are caused by user error or bent shift forks or the engagement dogs of the gears not meshing right. Keep in mind that motorcycle transmissions are not synchronized. In fact they are mini slam boxes. If you shift gears at the time that two meshing gears have their engagement dogs perfectly lined up with each other, they may bounce off each other instead of meshing. Instant false neutral.

I can see where reshaping them can help, but the most important thing would be to make sure there is positive stopping of the detent arm in its pocket with no rotational walking. Making them too shallow like seen in the picture is a recipe for troubles later.

Yes I have done this. No not to a KLX and no it surely did not look like that when I was done. Round off sharp edges only, polish the shit out of it and do not modify the shape of the detent pocket. No need to bother whit preloading the detent arm spring if done right. Preloading the spring for more pressure is a band aid for poorly reshaped stars.

 

Shift mechanisms are very sensitive to friction as it relates to the shift drum rotation.

Add it all up:
detent arm roller on the surface of the peaks and valleys of the "star"
detent arm roller bushing rotational friction on the detent arm rivet
friction from the drum rotating in the cases.
friction from the shift forks sliding on the shift drum
friction from the shift forks sliding the gears on the transmission shafts
Any friction you have - is not such a good thing. Less is better.

Shift mechanisms are sensitive to the amount of pressure the detent arm pushes on the particular shape of the "star" peaks and valleys.

But - the more pressure on the detent arm, the more friction in the rolling components. And the more foot pressure required to shift.

So - to eliminate some friction by polishing is a cost effective move in the right direction.

I usually do a polish and an arm from Factory Pro with a bearing on it.

So - I think that Factory Pro has a klx250 / 300 micrbearing'ed arm.

Marc99

 

He was taken back by your soliloquy and felt the need to be part of this wonderfully dead thread! Newbs...they never look at the date...

 

What did I do wrong?

Marc99

 

You revived a thread where the OP had already fixed his problem and STATED that he did... You also decided to make that your first post...

 

Did you learn anything from my post?

Marc99

 

don't worry. it's not his brain that's heavy...if you know what I mean.

 

Whether or not I learned anything or not is not the point, you don't bump an old that was solved a long time ago :angry7: