How Much Backlash Should the Clutch Hub Have

[Guest]

The above question says it all. I have pulled the clutch apart to replace the broken clutch hub that fits on the front transmission shaft. I have just received the new (used) one from the states. I installed it and torqued to 40 ft/lb.

I noticed when the transmission is in 1st gear that this inner clutch hub can be rotated about 1/3 of a revolution before the output sprocket achieves any movement. Is this normal?



Above: See index marks on inner hub and clutch basket at 12 oclock position.




Above: Index mark now is at the 8 oclock position.

I noticed when the transmission is in different gears that this backlash or play (call it what you want) is different. 2nd gear is about 1/8 of a revolution. The other gears are all between 1/8 and 1/6th of a revolution.

The reason I ask is that on the last ride (about 120 miles) when moving away from rest the clutch would take up as normal and then I could feel a definite give in the driveline. So to explain further when the clutch plates had engaged there was still a lag before the bike moved off, like a certain amount of play had to be taken up before the bike would move away. Once going along the transmission and clutch were fine.

Is this amount of play normal in 1st gear and if not what is the problem?

Thanks.

[Nessism]

I think what you are describing Don is freeplay in the transmission engagement dogs. Perfectly normal although your visual reference does make one think. If the back wheel is off the ground you may be combining the transmission free play with that of a slack chain too. Not sure, I've never measured the play as you have.

[GregT]

There is usually more backlash built into the 1st gear dogs as this gear is selected while stopped. 2nd and up usually have less as less is required.
Even if you had a broken dog the backlash would be as original.
The only way it is larger than original is if someone has done an excessive backcutting job on the dogs...

[Suzuki_Don]

Thanks guys, I knew someone out there would know about this. Glad to know it is normal. It might just be that because it is a six speed transmission the backlash is greater allowing for a lower ratio gear. I was thinking the backlash I was feeling was where the two gears mesh with each other (but I knew there could not be that much backlash there) I forgot about the dogs that had to engage when the gears slide along the respective shafts.

That's great news, now I can put it back together and do some more riding.