1st gear help

[robichjr]

For those of you who are intimately familiar with the 250x or 300ex transmission:

Can you help me to identify which shift fork and gears are associated with first gear? I have a 1987 250x that has issues with first gear slipping.

I've been told that the wrong oil could cause the clutch to skip, but it's only doing it in first. I could be wrong, but wouldn't it slip in all gears if it was the clutch?

I am going to fill, flush, and fill with Amsoil 4 stroke motorcycle oil to test that theory first. However, if that doesn't work the wrenches are coming out. Anyway, if I have to go into the case, I may want to have some parts staged (shift fork, thrust washers, etc....) I am putting this out there because I don't have my shop manual handy at the moment.

Thanks.
http://www.bikebandit.com/PartsBandit/Assets/schematics/Honda/HJ100019.gif
http://www.bikebandit.com/PartsBandit/Assets/schematics/Honda/HJ100021.gif

[GPracer2500]

What exactly to you mean by "...issues with first gear slipping". Is it slipping out of first back into neutral or ???

[robichjr]

It does not slip out of gear. When I am in first gear, with the clutch completely engaged, it seems to skip. It is sporadic though.

[GPracer2500]

Originally posted by robichjr
It does not slip out of gear. When I am in first gear, with the clutch completely engaged, it seems to skip. It is sporadic though.

I'm still not sure I understand what it's doing.

When it "skips" do the rpms shoot up real fast?
Or is does the whole quad shudder, or??
If you let off the throttle does the "skipping" stop?
Does it only happen when your really laying into the throttle--putting the engine under a lot of load?

[robichjr]

I don't try to accelerate hard in first gear because of this. When I am motoring slow in first, it will seem to slip momentarily with a small increase in rpms then it will catch. It does not happen in recognizable rythm, it is sporadic. The only noise is that of the chain going slack then tight again. Like I said before, this is only in first gear.

[honda460ex]

My conclusion, if it is really only doing it in first gear, then yeah, my guess would be you have lost a tooth or more on 1st gear inside. I shattered a gear completely in my 400ex. But I shattered the inner gear that drives the whole tranny off of the clutch basket, lol, if that makes sense. But anyway, It shuttered and jerked like that until I finally destroyed every tooth on that gear. If you are running a synthetic oil, then yeah, it can cause the clutch to slip a little sometimes, but not like that. It will primarily slip in the taller gears when you have a load on the bike or trying to accelerate quickly. As of which gear to point out in the diagram, I couldn't tell you off hand. I've rebuilt two 300ex's, but I couldn't tell you which gear still. My advice, from the info you gave, I would be splitting the cases and seeing exactly what all has been damaged before I start just buying parts. Metal shavings from that gear can cause a lot more issues if the motor has been ran to much to long.