"CLUNK" sound in drivetrain

[OVR4D]

I didn't read that. I thought he said that he feels the clunk after getting back on the gas.

 

[Redbeard]

I went back and re-read the first post again. I miss-read what 4strokeluvr111 said:

SYMPTOMS:
From a dead stop and I apply the throttle the sled moves forward with a noticeable CLUNK sound in the drivetrain.
If I am freely rolling down a slight incline and hit the throttle...same CLUNK
If I slowly feather the throttle and engage everything slowly there is no clunk...just a nice quiet engagement.

OVR4D, I apologize. He did say clunk when he coasts and then hits the throttle; not clunking while coasting.

Hey 4strokeluvr111, I misunderstood what you were saying. I interpreted your post as you were hearing clunk..clunk..clunk..continuously. If it's just a clunk at engagement or hard throttle, OVR4D might be onto your problem...sorry!

 

[4strokeluvr111]

I went back and re-read the first post again. I miss-read what 4strokeluvr111 said:

SYMPTOMS:
From a dead stop and I apply the throttle the sled moves forward with a noticeable CLUNK sound in the drivetrain.
If I am freely rolling down a slight incline and hit the throttle...same CLUNK
If I slowly feather the throttle and engage everything slowly there is no clunk...just a nice quiet engagement.

OVR4D, I apologize. He did say clunk when he coasts and then hits the throttle; not clunking while coasting.

Hey 4strokeluvr111, I misunderstood what you were saying. I interpreted your post as you were hearing clunk..clunk..clunk..continuously. If it's just a clunk at engagement or hard throttle, OVR4D might be onto your problem...sorry!

No worries .jk! Have a for me OK??!!!

I've had the secondary apart in recent weeks putting in new buttons and polishing up the helix. Also trying different settings (60-70-80) to gage effect on WOT RPM's. That was one of the things I checked early on was to make sure the secondary was binding up and not fully closing. But I will look again.

 

[Yamadog]

Can't remember but think the 05 is the mono shock if it is I broke the interior of the receiver for the control rod on 2 rx's and 1 apex and as the sled goes from on power to off or otherway that rod clunks.

Also there is plastic washers on the rod to prevent metal on metal contact and if they are gone it will do the same thing

 

[OVR4D]

OVR4D, I apologize. He did say clunk when he coasts and then hits the throttle; not clunking while coasting.

No apology necessary jk.

111: A binding secondary, or one that is engaging more abruptly could produce the symptoms you describe. You might also experience more aggressive backshifting with engine breaking, which would be more noticeable at slower speeds.

When your secondary is working as it should, the sheaves should close (backshift) less abruptly as the centrifugal force holding the secondary open is more slowly overcome by the spring at higher speeds. but a binding secondary might remain open longer at slower speeds and then suddenly slam back together when whatever is causing it to bind frees up and the spring is then able to aggressively close the sheaves. 4 stroke engine breaking at slower speeds will exaggerate or amplify backshift if the secondary is binding.

As for the clunk on engagement, it's really just the same principal in reverse. If something is holding (binding) the secondary from opening until enough force is applied to overcome this binding, the initial engagement will be abrupt, creating the clunk you describe.

Not saying this is your problem. Just a possibility.

Are you able to run the sled under some small load and still observe the clutch engagement? Can you get someone to sit on the sled and slowly increase throttle while you watch the engagement?

 

[4strokeluvr111]

Well, it appears that the CLUNK is related to the fact that I have a M10 suspension in the sled and I prefer to run the track loose. Talked to my local Yamaha dealer and he said that the steep approach angle of the M10 doesn't allow for the track to wrap around the drivers like a stock Yamaha skid would. Combine this with soft, sticky snow and you have a recipe for the CLUNK. Don't know if this makes sense but.....

So I came home and tightened the track not quite one full turn on each adjuster and it did help. The CLUNK isn't gone but it's much better. I get underneath the sled and listen to the drivers/track mesh up and it's a pretty loud sound.

Tomorrow I think I'm going to go a bit tighter on the track and try it again. I also want to look at what brand new drivers look like and compare them to what's on there now.

I feel pretty stoopid about this whole thing......I guess I'm trying to fix something that maybe can't be fixed. Thanks for all the suggestions and help!!!!

 

[thor452]

I have a slight concern on the chain tightness you said you went tighter and looser with it and maybe i am reading into this to much but the proper wat to adjust that is to bring all the slack in the chain to the tensioner side of the gears can be done bu truning the brake rotor or the secondary in the proper direction cw on brake ccw on secondary till it starts to move track. next loose the jam nut on the adjuster .next turn in the adjuster till it is as tight as you can get it by hand then back off 1/4 turn. next lock down the jam nut without changing the setting. if the chain is not to speck it will cause the exact symptoms you are discribing. fwiw maybe you already did this.

 

[4strokeluvr111]

I have a slight concern on the chain tightness you said you went tighter and looser with it and maybe i am reading into this to much but the proper wat to adjust that is to bring all the slack in the chain to the tensioner side of the gears can be done bu truning the brake rotor or the secondary in the proper direction cw on brake ccw on secondary till it starts to move track. next loose the jam nut on the adjuster .next turn in the adjuster till it is as tight as you can get it by hand then back off 1/4 turn. next lock down the jam nut without changing the setting. if the chain is not to speck it will cause the exact symptoms you are discribing. fwiw maybe you already did this.

When I was trying adjusting to see if the condition would get better or worse, I went "loose" on the chain then tight (not backing off the 1/4 turn) and the condition didn't change. If memory serves I did get the slack out as you described. I might just double check the adjustment to be safe.

On another note I might just bite the bullet and buy and install extrovert drivers. BUT I have a potential clearance issue with the front arm on my M10. I only have about 3/4" of clearance between the existing driver and the limiter straps that wrap around the arm.

I'm going to call Wahl Bros. to get their suggestions. Possible Team FAST as well.

 

[Redbeard]

On another note I might just bite the bullet and buy and install extrovert drivers. BUT I have a potential clearance issue with the front arm on my M10. Where an extro driver would poke thru the track openings I only have about 3/4" of clearance between the existing driver and the limiter straps that wrap around the arm.

You may simply be able to move your front arm back about an inch on the tunnel and rails to clear the driver teeth. The lower front shock mount moves back an inch as well. Fast offers a kit to do this, but talk to Brian at Fast to be sure. He is real good to talk to about these kinds of issues.

Here is a post of Motorheads that addresses this issue. It has pics of what Fast sent him to correct his front arm and driver clearance issue. His is an M20, so check with Fast to be sure if it would work for an M10:
http://www.ty4stroke.com/viewtopic.php? ... highlight=

 

[4strokeluvr111]

On another note I might just bite the bullet and buy and install extrovert drivers. BUT I have a potential clearance issue with the front arm on my M10. Where an extro driver would poke thru the track openings I only have about 3/4" of clearance between the existing driver and the limiter straps that wrap around the arm.

You may simply be able to move your front arm back about an inch on the tunnel and rails to clear the driver teeth. The lower front shock mount moves back an inch as well. Fast offers a kit to do this, but talk to Brian at Fast to be sure. He is real good to talk to about these kinds of issues.

Here is a post of Motorheads that addresses this issue. It has pics of what Fast sent him to correct his front arm and driver clearance issue. His is an M20, so check with Fast to be sure if it would work for an M10:
http://www.ty4stroke.com/viewtopic.php? ... highlight=

WOW! Thanks for the info .jk!!! Awesome!

 

[Redbeard]

You're welcome!
The front arm on my M20 is 1" further back for the same reason, but Fast shipped it that way when I bought it.

 

[Jeffz]

Well, it appears that the CLUNK is related to the fact that I have a M10 suspension in the sled and I prefer to run the track loose. Talked to my local Yamaha dealer and he said that the steep approach angle of the M10 doesn't allow for the track to wrap around the drivers like a stock Yamaha skid would. Combine this with soft, sticky snow and you have a recipe for the CLUNK. Don't know if this makes sense but.....

So I came home and tightened the track not quite one full turn on each adjuster and it did help. The CLUNK isn't gone but it's much better. I get underneath the sled and listen to the drivers/track mesh up and it's a pretty loud sound.

Tomorrow I think I'm going to go a bit tighter on the track and try it again. I also want to look at what brand new drivers look like and compare them to what's on there now.

I feel pretty stoopid about this whole thing......I guess I'm trying to fix something that maybe can't be fixed. Thanks for all the suggestions and help!!!!

My M10 in my Phazer has developed a noticeable clunk like you describe. I haven't had any luck figuring out what it is, but this post makes sense. I run my track on the loose side.