250 sx shift issues


8 replies to this topic
  • mototack

Posted June 10, 2013 - 07:38 PM

#1


I did a search on this issue didn't see it discussed. We have
encountered a pattern with four different 250 sx bike 2012-2013
bikes,all four of the riders complained about difficulty shifting from 2nd
to 3rd while under heavy acceleration. (could not be duplicated under
lesser acceleration attempts) (shift problem usually occurred while
pulling hard out of a corner) Eventually the riders couldn't shifting
from 2nd to 3rd until repairs were made, with a little research I
found some information on this issue but little on the cause or
suggested fix.

Our local Colorado speed shop LSE (Leavitt Speed Equipment
http://lseracing.com/) developed a repair that has successfully fixed
this issue on all four bike. It included polishing the SHIFT DRUM and
replacing the wheel on the LOCATING LEVER with an actual bearing.

I guess my question is has anyone else encountered this problem is
this a prevalent problem or an isolated issue?



  • rjg

Posted June 10, 2013 - 07:45 PM

#2

Next time you have one apart can snap a picture of the modifications and post a picture. I have experienced the same problem. When under hard acceleration second to third won't shift. Even pulled clutch in and tried shifting but can't feel the click of third gear and when releasing the clutch it is still in second of course. During the shift and clutch pulling I am not letting off the gas, just holding it on.

  • harryhandshake

Posted June 10, 2013 - 08:37 PM

#3

some guys were complaining of a shift problem but i think it was the spring on the claw sliding plate. maybe the spring isnt strong enough to always push the claw sliding plate back out or there was some burs on the sliding plate that was causing to much resistance for the spring to overcome. but if that spring cant push the claw back out, then the gear shift lever will still move up and down normal but it wont grab the dowel pins on the shift star. and thus wont shift to the next gear. sounds like what happened to rjg. ive got the '13 and havent encountered any issues but some folks have just stretched the spring out alittle and that probly does the trick. or look at the sliding plates for burrs, maybe chamfer all the edges alittle with a dremel so it doesnt have a chance to bind up

Edited by harryhandshake, June 10, 2013 - 08:40 PM.


  • mototack

Posted June 11, 2013 - 01:42 PM

#4

Here's a photo of mod. note the locating lever wheel has been changed to a bearing. The bearing moves over the drum smoother and progresses into the drum indexes with less residence. I have heard that the slide plate spring is weak and folks have modified it with some success. We choose to remove KTM's wheel and replace it with a bearing and polish the drum surface. Now after a month of riding none of four riders have had any issues with 2nd to 3rd hanging up.

Posted Image
file://localhost/Users/mike/Pictures/iPhoto%20Library/Modified/2013/May%208,%202013/DSC_0029.JPG

  • harryhandshake

Posted June 11, 2013 - 07:56 PM

#5

i thought the stock lever arm did use some sort of bearing ? if you look it appears to be a ball bearing http://www.ebay.com/...1485c2b&vxp=mtr

Edited by harryhandshake, June 11, 2013 - 07:58 PM.


  • mototack

Posted June 12, 2013 - 01:22 PM

#6

[color=#222222][font=Helvetica Neue', Arial, Verdana, sans-serif][size=4][background=rgb(255, 255, 255)]KTM uses a wheel that rides on an axle. I replaced it with a true roller bearing. [/background][/size][/font][/color]

  • harryhandshake

Posted June 12, 2013 - 04:28 PM

#7

maybe they changed on the new bikes. they were using a ball bearing style like the link i posted

  • josko

Posted June 12, 2013 - 09:20 PM

#8

I had similar problem with my -11 250sx and this mod fixed it perfectly:

  • eins4eins

Posted June 13, 2013 - 01:00 AM

#9

i own a '12 SX 250 and have problems with the shifting also...no matter which gear, when trying to shift under full load i end up being in the same gear as before. i have to pull clutch and let the revs go down a bit before the gear will jump in.
i rode the bike 38h till now and those problems occured at last weekend.

in a german forum many people replaced following parts and the problem was fixed. I ordered those parts and will install them hopefully on friday.

[color=#333333][font=Verdana][size=3][background=rgb(250, 250, 250)]54834015000 SHIFT LOCATING DRUM 2003 [/background][/size][/font][/color]
[color=#333333][font=Verdana][size=3][background=rgb(250, 250, 250)]54834005044 SHIFTING SHAFT CPL. 03[/background][/size][/font][/color]


here are some pics of the parts i am going to replace. you can see some wear on the locating drum, hopefully this causes the problems, as i had no problems the first 35h i rode the bike

Posted Image
Posted Image




 
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