rm125 gearbox problems

[simon1]

my bike has started jumping out of gear and seems to be more difficult to select.it seems to be mainly second that it slips .any ideas as the gearbox was rebuilt 6 months ago with a new selector.also i seem to keep losing the clutch when riding in bogs etc.. are the two problems connected?it mostly slips out of gear at maximum revs.also seems to worse after i have been riding for a while.

 

[simon1]

well i stripped the gearbox and inspected everything,put it back together with a new clutch and the thing still slips out of 2 nd gear. surely somone can help?

 

[marcusgunby]

Sounds like the dogs are worn on 2nd gear-Suzukis have had gearbox problems as long as i can remember-sorry its just the way they are.

 

[HGaither]

dogs

I would agree with Marcusgunby, if the edges of the engaging dogs are slightly rounded it's over. But what does Suzuki do differently that would make them more prone to wear? Seems like everybody would have basically the same heat treating process and use the same metals.

 

[darringer]

Simon1, when you had the tranny apart did you check the thickness of the shift forks? I've had problems in the past with the forks wearing and the gears don't engage completely. Good luck!

 

[simon1]

thanks for the replies guys.

every thing in the box looked good but i will have another look. the 2nd and 6th gears + a fork were changed at the rebuild before.after phoning a suzuki dealer yesterday he thinks the drum that 2nd and 6th gears run is worn and thats what caused those gears to go again?

apart from this problem the bike has been great!

 

[jmics19067]

I think the inheritted problem with suzuki gears is that the dogs on the gears are either cut flat or very little back taper. Makes for extremely smooth shifting when new but there is very little to help hold it in gear when worn. A very general loose idea of figuring out your problem is if it pops out of gear while accelerating it is probably not all the way in gear or if you have trouble finding the next gear I owuld say it is somewheres in the shifting mechanism. If it is popping out of gear while you shut off the throttle the gears are worn. Extremely vague and probably only about 75% correct.

 

[Hucker]

I don't know if this will help but my 90 RM250 used to do the exact same thing. Slip out of 2nd into a "false" neutral. Well after getting it stuck inbetween 3rd and 4th and a $300 repair job I finally found the problem. I was using 75W gear oil. Big mistake, as said before our bike's transmissions aren't the greatest design out there. I have been using Silkolene Medium 85W Gear oil and have NEVER had this problem again. Now the clutch pull is a little harder with the heavier oil, but I have never had tranny problems since.