Huck Fonda
Well-known member
- Joined
- Sep 28, 2007
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The subject of clunkiness in the trans of the AE ( and std) models is well discussed, but appears poorly addressed. I have been driven to the point of frustration both by my own experiences and by the silliness of some of the posts here and elsewhere. So here's what I did...
I, like many of you, assumed to some extent that the stack up of clearances in the final drive, middle drive, etc. was too much and that I was going to have to go in and shim the living daylights out of the whole mess. Then I started thinking about that spring loaded damper on the middle drive shaft, and how that should be able to quell the little bit of "slop" that exists, and yet it wasn't. Needed to check it out.
The FSM says to check the middle drive gear, first step is to drop the motor. Uh, no. I figured if I took off that little round cover on the right side, I ought to have a pretty good look at things. I was right, as usual.
Took the water pump loose first. Three bolts, no leaks, just enough hose slack to pull it out of the way and get at the third bolt holding the aforementioned cover in place. Three bolts out of the cover, and boom, there it all is. You can see the spring dealio and the middle driven gear plain as day. I had the bike in gear, and rolled the tire back and forth and observed the results. The "slop" between the middle drive shaft and the rear wheel is minimal. Just hold the end of the shaft and wiggle the tire, and you'll see that the stack up of clearances is pretty small. So where does all that play come from?
The middle driven gear is splined to its shaft (duh), and constantly meshed with the middle drive gear (another duh). Well the middle drive gear is also splined to its shaft. So what? well think about it. If the (lets call it the countershaft) countershaft is being rotated indirectly by the rear wheel, what's stopping it? At any given time, in any gear, the only thing that really makes connections between the main and drive shafts is the engagement of the "slider" gears.
In a constant mesh transmission, there are basically two types of gear, fixed and free-wheeling. The fixed type are splined to the shaft, and always rotate with the shaft. They are also always meshed to a free-wheeling gear on the opposite shaft. This allows for different rotaional speeds between the shafts. Sliders are always fixed gears, and move back and forth to engage (usually) free-wheelers. What does all this mean?
In short, it means that the clunk is actually the play that exists between the engagement dogs of whatever gears happen to be locked together. Since the dogs have relatively large gaps in them to facilitate engagement and disengagement, the resulting play can be pretty large.
So there really isn't a way to "fix" it. Throttle control, cable adjustment, correct idle RPM, and proper shift timing will result in silky snicks. Ham fisted or hypothetical efforts will yield little but growing frustrations.
Hope this helps, sorry for using what will probably be too many words for some of you.
I, like many of you, assumed to some extent that the stack up of clearances in the final drive, middle drive, etc. was too much and that I was going to have to go in and shim the living daylights out of the whole mess. Then I started thinking about that spring loaded damper on the middle drive shaft, and how that should be able to quell the little bit of "slop" that exists, and yet it wasn't. Needed to check it out.
The FSM says to check the middle drive gear, first step is to drop the motor. Uh, no. I figured if I took off that little round cover on the right side, I ought to have a pretty good look at things. I was right, as usual.
Took the water pump loose first. Three bolts, no leaks, just enough hose slack to pull it out of the way and get at the third bolt holding the aforementioned cover in place. Three bolts out of the cover, and boom, there it all is. You can see the spring dealio and the middle driven gear plain as day. I had the bike in gear, and rolled the tire back and forth and observed the results. The "slop" between the middle drive shaft and the rear wheel is minimal. Just hold the end of the shaft and wiggle the tire, and you'll see that the stack up of clearances is pretty small. So where does all that play come from?
The middle driven gear is splined to its shaft (duh), and constantly meshed with the middle drive gear (another duh). Well the middle drive gear is also splined to its shaft. So what? well think about it. If the (lets call it the countershaft) countershaft is being rotated indirectly by the rear wheel, what's stopping it? At any given time, in any gear, the only thing that really makes connections between the main and drive shafts is the engagement of the "slider" gears.
In a constant mesh transmission, there are basically two types of gear, fixed and free-wheeling. The fixed type are splined to the shaft, and always rotate with the shaft. They are also always meshed to a free-wheeling gear on the opposite shaft. This allows for different rotaional speeds between the shafts. Sliders are always fixed gears, and move back and forth to engage (usually) free-wheelers. What does all this mean?
In short, it means that the clunk is actually the play that exists between the engagement dogs of whatever gears happen to be locked together. Since the dogs have relatively large gaps in them to facilitate engagement and disengagement, the resulting play can be pretty large.
So there really isn't a way to "fix" it. Throttle control, cable adjustment, correct idle RPM, and proper shift timing will result in silky snicks. Ham fisted or hypothetical efforts will yield little but growing frustrations.
Hope this helps, sorry for using what will probably be too many words for some of you.
