Chain jumping?!

[Ricks426]

Last season on my 00 YZ426f my chain started jumping around, so I changed the chain (did X ring) its what i always run. That wasnt it. So i changed my front sproket, still jumping.(only when you re lugging the engine, not under load.) The back sproket looks good still. Also changed the chain block to BRP full plastic type. When I had my chain off and in gear, you could move the front sproket about a 1/4 turn before it lashed with the gear. Hoping the tranny isnt gone. Anyone else experience this?

[rickyz1984]

i had the same thing on mine and it was the tranny i'm just in the middle of putting it back together now it was my first time working on a 4t but with the manual it was not to hard

[grayracer513]

Does this "jumping" only happen in one gear, as in 1, 2, and 3 are fine, but it acts up in 4th, then if you go to 5th, it acts normal again?

[Ricks426]

Does this "jumping" only happen in one gear, as in 1, 2, and 3 are fine, but it acts up in 4th, then if you go to 5th, it acts normal again?

It does it when ever im lugging the engine or crusing down a trail or road, but not when im torquing on it.

[426 NOOB]

It does it when ever im lugging the engine or crusing down a trail or road, but not when im torquing on it.

its gotta be chain slap. All yzfs do it. If theres no jumping out of gear, and it does it in every gear, it has to be slap. Under a load it would make the jumping worse if it were the tranny, from what i have seen. Check your chain tension. Should be 1.8-2 inches of slack with rear wheel off the ground and measured above the farthest back slider bolt.

[Ricks426]

its gotta be chain slap. All yzfs do it. If theres no jumping out of gear, and it does it in every gear, it has to be slap. Under a load it would make the jumping worse if it were the tranny, from what i have seen. Check your chain tension. Should be 1.8-2 inches of slack with rear wheel off the ground and measured above the farthest back slider bolt.

I don't think its chain slap because it does it after i tighen it up. I use 2 fingers right at the back of the chain slider, its a little tight, but thats how I like it. Im going to change the rear sproket and see if that cures my problem. Keep the suggestions comming, I want to look into everything before I tare this beast apart.

[grayracer513]

I don't think its chain slap because it does it after i tighen it up. I use 2 fingers right at the back of the chain slider, its a little tight, but thats how I like it.

How do you like broken hubs?

That's one of the things that happens when you run the chain tighter than the minimum listed in the manual. (1 5/8" at the rear of the chain slider with the bike off the ground)

[426 NOOB]

How do you like broken hubs?

That's one of the things that happens when you run the chain tighter than the minimum listed in the manual. (1 5/8" at the rear of the chain slider with the bike off the ground)

i agree people think that the chain makes too much noise and try to correct it by over tightening the chain. Then they have worse problems than noise.

[grayracer513]

...Then they have worse problems than noise.

Although, there is usually a very loud noise associated with any such problem.

[426 NOOB]

true. it is scary when you hear it and have no idea what it could be. Especially with a tm slider. haha:busted:

[Ricks426]

How do you like broken hubs?

That's one of the things that happens when you run the chain tighter than the minimum listed in the manual. (1 5/8" at the rear of the chain slider with the bike off the ground)

I guess I have fat fingers then cause they're 1 3/4" together:smirk: right in spec. I'm hoping it's just the sprocket is worn.

[Polar_Bus]

true. it is scary when you hear it and have no idea what it could be. Especially with a tm slider. haha:busted:

You should'a heard the chain slap of my ol' '82 RM125....

that RM chain slappin' sounded like a bamboo pole whacking a stop sign !!!

Edited March 12, 2010 by Polar_Bus

[426 NOOB]

that girl chain slappin' sounded like a bamboo pole whacking a stop sign !!!

haha. never heard that one. Good stuff:thumbsup: