2000 426 4th and 5th gear

[LEMMON1]

idk i didnt put this on here earlier..suppose i keep forgettint o. anyway back to point.

ffirst throguh 3rd work as advertised. but all of a sudden one dayi took it out to the track my 4th and 5th gears acted weird...almost eithe rlike a engagin disengagin thing or like its missin teeth cause it kinda chatters u could say..

well when i cahnge the oil i didnt see any metal or anything in it so i assum its not nessarlily the gears?? what else could it put sicne i ssume im gna hafta split the case anyway to fix it

[Zn3b]

yep, you're gunna have to split it. I would take a look at your shift forks and see if any are bent. I would also look at the dogs on the slider/freewheeler gears for 4th and 5th and check for wear. If the edges of the dogs are worn, they tend to want to not to lock. Hope that helped.

[greengoose999]

i have just replaced my box ts week as i had very similar problem. mine was slipping 4th. no metal shavings when the oil was drained but when i split the cases there was metal everywhere and teeth aswell. 2 gears had nearly all teeth removed.

as the above said i would check the dogs on all gears as the slightest round on the dogs will cause it to slip later on.

i had to replace 7 gears but that was just me being overcautious. luckily everything else survived and got it all running last night and its as good as new.

good luck..

[LEMMON1]

did u guys rebuild everything since it was already split or no? like the cranks bearins pistion...pretty much a full rebuild or just what ya needed to for hte most part?

[greengoose999]

just double check your shift forks for wear. and also your selector drum. most common wear place on the drum is from 4th to 5th at the peak. i didnt replace any bearing as there wasnt anything wrong with them. maybe you might want to do a cam chain as they are only cheap. and while its apart you can freshen it up with a new set of rings if they havnt been done for a while.

and you will need nearly a full gasket kit for the rebuild aswell.

if you find metal shavings in the case no doubt there will be heaps inside your flywheel and hope it hasnt destroyed your stator. might need to pull that stator out of the cover to remove all metal filings.

[grayracer513]

The fork will be damaged, but they aren't the cause of the problem. The lugs on the gears are:

https://www.thumpertalk.com/forum/showthread.php?p=5351185#post5351185

[LEMMON1]

that sounds almost exactly what im experiencin

[Zn3b]

you're gunna need to get new tranny shafts and forks. the forks are bent as a result of the dogs (lugs) having wear. i looked on ebay and i couldnt find a tranny for your model, but for a yzf450, shafts were going for $150 usd. so look around i guess, wont bee too expensive (if you know how to install ?)

[LEMMON1]

wont bee too expensive (if you know how to install ?)

ya that is the key though lol guess i will hafta find out lol

[grayracer513]

you're gunna need to get new tranny shafts and forks. the forks are bent as a result of the dogs (lugs) having wear. i looked on ebay and i couldnt find a tranny for your model, but for a yzf450, shafts were going for $150 usd. so look around i guess, wont bee too expensive (if you know how to install ?)

There is no direct relationship between this condition and either of the shafts in the transmission, or any reason to suspect they would need to be replaced.