New gears on final drive but they sound and feel terrible

[humanshield]

Ok,

so today I installed a new set of final drive gears.   I removed the stock 3.71 set and installed a 2.88 set.

I haven't ridden it yet, just hand spinning the rear wheel on the center stand.

everything went fine (or so it seemed) and I felt the job was done right.  No issues.

UNTIL,,,,I put the rear wheel back on and spun the tire.   Lots of grumbling, vibrations, noises and it just sounds terrible.

That said, it feels fine when turning it slowly or gently moving the tire back and forth.  Everything feels normal.   It's only when I spin it fast that it seems to have a problem.

Ok, now that said, it could just be the new gears don't mesh perfectly well together and it'll smooth out with miles.   That's what I'm fairly certain of.   But I was wondering if others who have changed the final drive gears recall this kind of really roughness in spinning the wheel at first and if it went away after a while of riding it or.....

Was yours smooth from the beginning?

I'm inclined to take it all back apart and inspect everything....but I don't think I'll find anything.

[PirateLabs]

Jul 26, 2018 19:10:17 GMT -5 humanshield said:

Ok,

so today I installed a new set of final drive gears.   I removed the stock 3.71 set and installed a 2.88 set.

I haven't ridden it yet, just hand spinning the rear wheel on the center stand.

everything went fine (or so it seemed) and I felt the job was done right.  No issues.

UNTIL,,,,I put the rear wheel back on and spun the tire.   Lots of grumbling, vibrations, noises and it just sounds terrible.

That said, it feels fine when turning it slowly or gently moving the tire back and forth.  Everything feels normal.   It's only when I spin it fast that it seems to have a problem.

Ok, now that said, it could just be the new gears don't mesh perfectly well together and it'll smooth out with miles.   That's what I'm fairly certain of.   But I was wondering if others who have changed the final drive gears recall this kind of really roughness in spinning the wheel at first and if it went away after a while of riding it or.....

Was yours smooth from the beginning?

I'm inclined to take it all back apart and inspect everything....but I don't think I'll find anything.

Were you just spinning the empty axle?  Or, was it all back together with the clutch installed.  The reason I ask this is because, this is how I found my clutch bearings were going bad...spinning the rear wheel on the stand by hand.  This is also how I found that the next 3 replacement clutches were bad right out of the box.  At first, I thought it might be my gears but, spinning it with the clutch off it was near silent.  Just a thought but it may not apply here.

Others with new gears can say for sure but maybe there is a slight "break-in" period with new gears?  They might have to mate up with each other a bit and after riding gently for a while, I would dump the gear oil and ride a bit more.  These are new, machined surfaces that have never been mated with the other gears.  Again, maybe this is not the case either.  Brent should know as he rebuilt his gears and bearings when he smoked them with no oil that time.  See what he says.

Good luck,

Bill

[humanshield]

Thanks Bill,
Yeah, if others who did final drive gear changes chimed in it would really help. Maybe it's normal.

It's pretty simple to do. I'm considering taking it back apart and more carefully inspecting all the bearings. it could be a bearing.

Pretty sure everythings back together properly.