Hello world, i have an old Montesa, still in very good nick, just got it going after several years rest.

When I am changing gears it hits a neutral. I believe their could be something loose inside the box. any ideas.

Loughie

More info needed

Neutrals between which gears?

Upshifting or downshifting?

Does it happen when you shift with the motor stopped?

Is the shifter moving back freely after you shift?

Is the shifter moving all the way back to the mid position each time?

Did it have the problem before the several years rest?

Why do you think something is loose in the cases?

I suggest you post questions about your 172 in the twinshock or mechanical help forums

Edited July 27, 200620 yr by feetupfun

It will hit a neutral between any gear going up the gears or down the gears. The reason I think maybe something is loose is because it does hit a neutral when when ever it wants to, even with the engine turned off.

I have taken the side cover of the Right side and the spring that returns the lever into the centre is all ok.

everthing I can see on the outside looks to be moving corectly.

BR

Loughie

skype address loughie0001

I'll assume that you either don't know or that it shifted fine before the big rest.

It is possible that the indexing plunger is not holding the shift drum exactly in the right spot.

Common causes for this are old gummy gearbox oil on the shift drum and in the plunger cylinder and a drum indexing plunger spring that has relaxed.

I have started to take things apart.

I have taken the indexing plunger out and by moving the gear leaver by hand and looking into the plunger hole it works perfectly. When doing everything nice and slow.

When doing it fast like when riding that is when there was a problem. So I took the rake and pinion off the right hand side. There were 3 small bolts, and behind the plate there is a brass washer that has worn through and split in two. my guess is a piece of the brass washer was interfering with the changing mechanism

Your thoughts are appreciated

Sounds pretty likely you have found the problem. While you have it apart, see if you can work out why the washer was like that. Is it possible an impact on the shifter caused the problem?

i think I may have found the problem.

Is their a way I can post a photo of the plate that I think has failed.

I think it should have a piece of metal to stop the gear selector going to far, so what I think may have been the problem all along was, as I am changing gears I am pushing it through the gate, because the stoper was not their, I mean it broke, if I could post the photo, and some one can confirm my thoughts I would very much appreated..

I can always email the photos, if I can't post them.

Loughie

Inside that plate with the three screws there's a spring with two free floating teeth that engage the ratchet. I'll bet those teeth are worn and don't catch the ratchet every time. Take them out and sharpen them carefully on a grinder and reinstall with a longer/stronger or for no money, a stretched spring. Or, I know where you can get new ones.

Thanks for your reply,

The spring with two free floating teeth that engage the ratchet all look in very good condition.

are those free floting teeth supose to hit up against a stop, to stop the gear going to far and going to a neutral spot.

Is their a way I can post a photo of the piece I think is broken.