In need of help

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Aug 27, 2000
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#1
Ive got a problem with my bike that has me very confused. The bike is a 92' CR125, and this problem has just recently appeared after I let my clueless brother ride around on my bike. The problem is, when I have the bike in neutral, and pull the clutch in, the bike lurches forward and the engine bogs. How can this be? The bike idles fine with the clutch still engaged, but when I go to disengage it to shift to first, it seems to have the reverse effect, the bike starts to move. The clutch cable is new and properly adjusted, and the clutch appears to be fine. Any ideas what is causing this?
 
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#2
Unless someone can think of something else yeah that is pretty weird. Had to read the description several times to try & understand the symptoms.

Ok here’s my theory but it’s a bit shaky:

One of the shifting forks is bent & the pressure on the clutch to disengage it moves the input shaft (which the clutch is mounted on) enough to hook a gear which is closer than normal due to the bent fork.

It’s the only thing I can think of that may happen without anyone laying a spanner on it.

Love to know the definite reason. Keep us posted.
 
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#3
my Rm 125 was similar. Except when I m in gear and i hold the clutch in, I rev the bike a lil to keep the engine on, the bike wants to move forward a bit. but then I rode a 2001 Rm 250 and it was the same way to me. But adjust the clutch cable over on my bike too many times and it still wanna move forward but not like it used to. now i can just feel it wanting to pull forward but it would not move after the adjustments.
 
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#4
Motomadness, that’s just normal clutch drag. The steels are pushed away from the fibres but there will still be some drag against each other. This is translated to the input gear shaft that is meshed with a gear on the output.

What is weird in this case is the problem is when the bike is in neutral so the gears shouldn’t be meshed but obviously are in some naughty non factory approved way.
 

smb_racing

Master of None
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#5
what type of gear oil are you running?
too heavy of oil could result in pressure (sticking) between the clutch plates. Just a thought.
 

Jaybird

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#6
I don't know about the neutral situation, but my bike has done the same thing when in gear....but it was like 10 deg F outside. I was using motor oil at that time, I only use ATF now.
 
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#7
i have never heard of anything this crazy, but i am thinking that somehow your pressure plate might be contacting the clutch cover, and that may be stopping it, from slipping like it normally would when disengaged. does it make any noises when it does this???
 
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#8
Yeah guys you are missing the point. In the neutral position the gears on both shafts are not meshed to any fixed gears so they spin freely no matter what the clutch is doing.

Except in this case pulling the clutch is putting enough pressure on the input shaft to catch one of these gears against a fixed gear.

I mean how else can a connection to the rear wheel be made?
 
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#9
I have to agree with David. Something is causing one of the gear sets to engage when you pull the clutch in, so there must be pressure against one of the gears from something. A bent shift fork is the only thing I can think of that could be the culprit. I suppose there could be some problem with the shift drum, something causing it to be out of alignment instead of a bent fork.
 
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#10
Thanks for all the input. The problem still persits. Im having a buddy who knows what hes doing take a look at it. Ill let you all know what happens.