Kx250f transmission flaws

kwilson1611
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kwilson1611
Edited Date/Time 11/7/2015 3:53pm
I have a 2013 kx250f and Ik kx250fs have had a transmission problems were the bike doesn't shift well under a load and yes mine does this ! Is there anything any one has done to help it out? Mines especially bad when I'm high on the Rpms in 2 and try to shift into 3
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colintrax
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colintrax 11/5/2015 8:30pm
11/5/2015 8:30pm
Pull in the clutch
dazzlindino 11/5/2015 9:05pm
11/5/2015 9:05pm Edited Date/Time 11/5/2015 9:06pm
colintrax wrote:
Pull in the clutch
...then...shift....
colintrax
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colintrax 11/5/2015 9:31pm
11/5/2015 9:31pm
colintrax wrote:
Pull in the clutch
dazzlindino wrote:
...then...shift....
Then release clutch

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colintrax
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colintrax 11/5/2015 9:56pm
11/5/2015 9:56pm
dazzlindino wrote:
...then...shift....
colintrax wrote:
Then release clutch
mattyhamz2 wrote:
Then pin it until you need to shift again
When's the corner coming? Or was that jump actually a berm? Ah fuck it. Pin it to win it.
mattyhamz2 11/5/2015 9:59pm
11/5/2015 9:59pm
colintrax wrote:
Then release clutch
mattyhamz2 wrote:
Then pin it until you need to shift again
colintrax wrote:
When's the corner coming? Or was that jump actually a berm? Ah fuck it. Pin it to win it.
I don't know about you but I flip the bird to the corners as I jump them. Cut my lap times by about a full minute. You guys should try it. No one will ever beat you again.
kwilson1611
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kwilson1611 11/6/2015 4:14am
11/6/2015 4:14am
Of course I'm trying to shift and pull in clutch but it's hard to get it to go up in third especially under a Load
hillbilly
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hillbilly 11/6/2015 6:20am
11/6/2015 6:20am
There is nothing you can do without splitting the cases and looking at the shift drum.

Mite get lucky and pull the clutch cover off and inspect the detent wheel that follows the gear select drum,that is on the outside of the main cases. It is a spring loaded wheel on a arm and it could be hanging on the case or the star gear it follows has a little flaw on it.
Reefer Sutherland 11/6/2015 6:40am
11/6/2015 6:40am
kwilson1611 wrote:
Of course I'm trying to shift and pull in clutch but it's hard to get it to go up in third especially under a Load
sorry to hear that bro, but if you switched to two-strokes you'd have an erection in every gear.
ktm212
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ktm212 11/6/2015 6:56am
11/6/2015 6:56am
I haven't ridden a 250f that shifts good under power but my kawis I was shifting twice in the air to plan for straightaways and off kickers just to get it to shift. A good winter project, have the gear box done. I see you're in North Carolina, KB5 in Pennsylvania does great work at a reasonable cost, makes the bike shift like butter and unlocks some hidden ponies, up to 2 horses according to a few motor guys I spoke to. I've done it on my race bike and practice bike. It cuts way down on engine breaking too.

http://www.kb5ind.com/engine.asp
kwilson1611
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kwilson1611 11/6/2015 7:57am
11/6/2015 7:57am
ktm212 wrote:
I haven't ridden a 250f that shifts good under power but my kawis I was shifting twice in the air to plan for straightaways and off...
I haven't ridden a 250f that shifts good under power but my kawis I was shifting twice in the air to plan for straightaways and off kickers just to get it to shift. A good winter project, have the gear box done. I see you're in North Carolina, KB5 in Pennsylvania does great work at a reasonable cost, makes the bike shift like butter and unlocks some hidden ponies, up to 2 horses according to a few motor guys I spoke to. I've done it on my race bike and practice bike. It cuts way down on engine breaking too.

http://www.kb5ind.com/engine.asp
Is there something I can do myself to help the problem that you have found ?
Brent
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Brent 11/6/2015 10:38am
11/6/2015 10:38am
ktm212 wrote:
I haven't ridden a 250f that shifts good under power but my kawis I was shifting twice in the air to plan for straightaways and off...
I haven't ridden a 250f that shifts good under power but my kawis I was shifting twice in the air to plan for straightaways and off kickers just to get it to shift. A good winter project, have the gear box done. I see you're in North Carolina, KB5 in Pennsylvania does great work at a reasonable cost, makes the bike shift like butter and unlocks some hidden ponies, up to 2 horses according to a few motor guys I spoke to. I've done it on my race bike and practice bike. It cuts way down on engine breaking too.

http://www.kb5ind.com/engine.asp
kwilson1611 wrote:
Is there something I can do myself to help the problem that you have found ?
I have a few KX 250f's from 2010 to 2014, they all have shifting issues. Its a known problem with the KXF gearbox since about 2007 or so.

I had PC re work my gearbox on my 2012, it made a world of difference, but my wallet took a hit...
jhansen510
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jhansen510 11/6/2015 1:34pm
11/6/2015 1:34pm
Take the lower end apart yourself and have isf micropoloshing done on all the internal moving parts and gears for tranny. It will make a huge difference!
nm143
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nm143 11/7/2015 3:53pm
11/7/2015 3:53pm
I recently went through the transmission on my '13 kx250f, and there may be something else to check.

There can be a problem with 3rd gear on the tranny output shaft. The gear has a brass bushing pressed in it. The problem is that the bushing can sometimes slide partway out of the gear. This causes the gear and bushing to be too wide for the space where it sits on the shaft. As a result the gear doesn't freewheel properly. In my case the drag would prevent the rear wheel from spinning freely even when in neutral. (Rear wheel would stop before making one revolution when spun by hand.). Occasionally the bike would lurch ahead when idling in neutral. The drag would make shifting poorer because its almost like having a gear partially engaged.

I replaced the gear and the output shaft and its working well. Free'd up some power that was being lost too!

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