bike in third gear when I get down on it it buks and skips only in third gear what could be my problem

 

What year/model is your bike?

 

The typical issue is worn gear dogs and bent shift forks.. Tranny rebuild time..

 

Add a signature similar to mind on your year,make and letter model. Also add a little clarification of what it is doing. You are asking for a $100 diagnosis with a 50 cent description of your problem.

 

2010 Street glide 83000 miles

 

The dog teeth and or the female pockets on the side of the gears may be getting worn and rounded so it will not stay locked in.

 

Lets get this perfectly clear??�� On a transmission in a car, across the synchoro hub is a U shaped clip that has a small hair spring forcing it out. On the U at bottom is a v shaped bend that drops in a groove in the outer sleeve. All it takes to hold gear in. If that v gets rounded from a whole lot of shifts, car will pop out of gear.



What exactly holds a modern Harley in gear. I would guess it is the heavy spring on the detent arm that notches in the shift cam on the end with the 5 or 6 star shape v detents. The actual shift lever notches in on the other end with the pins indexed around that the internal shift paw pulls on indexs it and the slots slide shift fork that drags dog ring over engages gear range. All the actual gear teeth are always engaged. If you ever hear a rake, its the dogs, not actual gear teeth.

 

First off HD gear boxes don't have synchros. They are simple dogs or pins that fit into slots. (That is why HDs clunk when shifting.) What holds the ring in place against the digs is really a small back cut on the dog and inside the pocket on the dog ring. IIRC the angle is something like 2-4 degrees. What happens is the dog and dog ring lose that angle and the slots become worn to the point where the ring pushes away from the gear dogs and the shift fork bends. The common mistake for backyard mechanics is to see the bent/burned fork and assume it was the issue. The guy replaces the fork. The shift fork bends again and problem returns.

 

That reference on synchoro hub as noted in my post was for a car. And I have always though that that toe angle was what held the dog drive into the gears in on the older straight cut tooth gears since there is little side thrust like in the modern 6 speed with Helical gears that requires thrust bearings. When you go from throttle to coming off throttle using the engine as a brake, the drive dogs are going to bump back to the other face. So there has to be more then just the toe angle. And you did I think answer my question on that much force on the shift forks which are held in position by the star V on the shift cam

 

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