07 pops out of 2nd


4 replies to this topic
  • MTshirt

Posted March 06, 2008 - 11:35 AM

#1

I have not torn it down yet. It only comes out with a good load on it. A good size jump out of a turn . I am expecting to find worn cogs on the side of a gear or a bent shift fork. The bike does have a lot of time on it. I was getting the parts together to do a top end. I was not planning on splitting the case.
Is there a way to diagnose a tranny before I take it apart? I would hate to miss something and have to go back in.
I had to replace some of the trans gears in our 06 last year. The screws that hold the large weight for the balancer broke and messed it up pretty good.
I guess my son is just hard on the trans.

  • grayracer513

Posted March 06, 2008 - 12:54 PM

#2

You'll find both the worn dogs and the bent fork. The fork gets bent by the gears forcing themselves apart because of the worn dogs. You can know ahead of time that the second and fourth wheel gears (output shaft) and the #1 shift fork will need to be replaced, but there may be more that needs doing once you get in there and inspect everything.

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  • MTshirt

Posted March 06, 2008 - 01:53 PM

#3

Thanks

  • MTshirt

Posted March 07, 2008 - 03:43 PM

#4

Grayracer you are the man. You are spot on. I tore it down today. I think it will also need the 3rd & 5th wheel gears. Not worn as bad but showing wear.

I do have a couple of questions
The cylinder has some light colored spots in the bore. From specs to about a 16th of an inch. All at the top of the stroke. all on the frt side. You can just feel them with your finger nail. I have never seen this before. Any ideas?

The TT store does not show the 07 trans but does show the 06. Same gears?

Thanks again

  • grayracer513

Posted March 07, 2008 - 04:16 PM

#5

Check the part numbers here:

http://www.yamaha-mo.../starthere.aspx

The "spots" at the top of the bore are probably the result of the rings changing direction under pressure. The pressure on the rings is very high as the combustion cycle begins, and for just a fraction of a second at the top of the stroke, they stop moving and then reverse direction. What you see is the beginning of a pretty normal wear pattern.

There have been a very small number of '07's develop problems with the plating. Since I can't see it, you might want to run that by a really good Yamaha tech and have him look at it.

If it's OK, run a ball hone through the cylinder as described HERE and replace the rings.





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