another question, it is posible to remove just left side of the crackcase engine to reach the transmission parts?, oviouslly I would need to quit the engine from the frame

Are you sure that the shifting mechanism is working properly?

If it works sometimes I don't think the transmission is broken.

ohiomoto wrote on 07/04/19 at 04:19:17:
exactly the noise is a gear grinding noise

Yeah, that doesn't sound like a speed issue.  I mean wtf is a speed issue anyways???  I can put my bike into second from a dead stop.  

First, make sure the shift linkage is in good order.  Sometimes the rod that connects the shift lever gets bent and causes issues.  It's easy to check and easy to fix.  Not sure why it would only cause issues in second, but maybe you'll get lucky and it will be an easy fix.

Beyond that, I think you may be correct in thinking that this thing may need to come apart.  

Hi I will check the shifter mechanism and I let you know, thanks


ohiomoto wrote on 07/05/19 at 05:21:57:

I would  also be sure the clutch is adjusted , and you may need to change the length of the clutch throughout rod ( there are three different lengths you can order from the factory) as the clutch wears ,the clutch pack becomes narrower and the rod sticks out farther and may not at some point allow complete engagement , the rod shouldn't stick out more than about 12to 12.5 mm .

If someone was trying to hammer through the gears they could have bent the shift fork or chipped/rounded off the gear (or the gear dogs as norm92de said).

Either of those will make it not want to slip into gear all the time.  Or rattle and bounce out.

Usually this happens on 3rd or 4th gear though.  But I would exhaust other options first, including just living with it.

Splitting the cases and changing the gear and shift fork out is a bit of work, if its messed up.  And probably around $500 bucks in gaskets and parts while you are in there.

Regarding the gear shift linkage, make sure the shift lever moves up and down without hitting anything.  The shift from first to second gear may take a bit more lever movement since you must pass through neutral.  If the lever is bent or the linkage is out of adjustment, the travel might be limited.  The stop in the external gearshift mechanism should limit travel, not stuff like footpegs or the frame.  

After you make sure the gear shift linkage is in good working order and properly adjusted, I suggest you go through the "external gearshift mechanism" as outlined on pages 166 through 172 of the all inclusive Clymer manual.  Pay particular attention to the cam stopper (2) and it's associated spring (4).  If the spring is weak or broken, or the roller is heavily worn, the shift drum can rotate past the intended position and cause the gears to end up in between the desired position (like in between 2nd & 3rd rather than in 2nd).   Generally, a good indicator of stopper problems is difficulty finding neutral.  You having any trouble finding neutral?  Is your 2nd gear "grinding" issue only related to upshifts (i.e 1st to 2nd) or will it also occur on downshifts (i.e 3rd to 2nd)?