2nd gear bucking

[overboostin]

After getting my engine and wiring all done, I took the 650G out for a test ride. This is a replacement motor with 11k miles. First gear is fine but when switching into second the bike bucks and there's a metal rattle and clanking and doesn't really want to accelerate. When switching into third the problem goes away. Shifter fork issue? What should I be looking for tomorrow in the daylight?

 

[Guest]

Sounds like a blown out second gear.
Sorry bro
Look for teeth in your oil pan.

 

[overboostin]

Sounds like a blown out second gear.
Sorry bro
Look for teeth in your oil pan.

It's looking like pulling the motor and splitting the case?

 

[Guest]

You can peek at your tranny when pulling the oil pan. Plus you may find grusome bits in your pan.
I'd peek before splitting the cases.
It shifts into 4 and 5?

 

[overboostin]

When running on the center stand the bike can shift fine through all five gears with no noise, when under load when riding the second gear noise appears.

 

[Guest]

If it was the forks or drum you would have more problems than second gear.
Since this is a transplant do you still have the other motor?

 

[overboostin]

I do. One of the cylinders is shot but everything else on it is fine

 

[Guest]

A lot of work but you can do it.
You can turn the motor upside down and not take off the top end.
Practice on the junk motor first.

 

[overboostin]

So you think second gear is just shot?

 

[Guest]

Probably.......

 

[tom203]

Overboostin- still fighting those demons, what a pain! The 650 tranny is a little odd- second gear does double duty, it slides toward output shaft to make 5th gear by locking up the shaft to clutch input. Hard to explain. but look at attached pic. note the wide 2nd gear that has teeth that can engage the final output gear (this causes lock up) when it slides to right in pic. It's a compact arrangement, but seeing how 2nd gear is usually the most abused on a bike, it has its limitations.

 

[overboostin]

This bike has definitely been a problem child. Thanks for that picture Tom!

 

[tom203]

Here's a better view of the "lower" set of teeth on 2nd gear; understand that the output shaft (big bevel gear) is actually free to turn inside the main shaft in gears 1 thru 4- the two shafts are only locked by those "lower teeth" on 2nd gear

 

[overboostin]

Since the original motor has a good transmission I think I'm going to swap everything over to that motor, which would let me avoid splitting the cases. The dealership near me has the piston circlips so it looks like the teardown will happen tomorrow.

 

[tom203]

Since the original motor has a good transmission I think I'm going to swap everything over to that motor, which would let me avoid splitting the cases. The dealership near me has the piston circlips so it looks like the teardown will happen tomorrow.

I can almost remember when I was that ambitious. Hey did you see this beauty on RI Cl?
http://providence.craigslist.org/mcy/3659656033.html

Maybe Rhonda is good with demons- or something.

 

[overboostin]

I can almost remember when I was that ambitious. Hey did you see this beauty on RI Cl?
http://providence.craigslist.org/mcy/3659656033.html

Maybe Rhonda is good with demons- or something.

That's a pretty nice looking 650. If she would be willing to let it go cheap it may be a good pick up.