[Mailman]

When I launch hard on the banshee, I hear and feel a chain chatter or grinding coming from the rear of the bike. Any of you run into this problem? I have seen a similar issue on other banshees when the chain is too loose. The bikes only do it under full load from a dead stop.
I have a 100+ hp banshee with a +8 swinger. The chain is in adjustment. It does it from a second gear launch and when the bike shifts to third. It sounds like the bearings are toast in the carrier or the chain is skipping teeth on the rear sprocket.
Could the bearings just be binding on the carrier? (No play in bearings)
The bike doesn't do it in 4th and up. It also won't do it in 1st through 3rd if the load is reduced.
If it is chain related, then could a chain tensioner help?

Mailman

[Koolguyson]

Mailman, on 25 October 2009 - 08:38 PM, said:

When I launch hard on the banshee, I hear and feel a chain chatter or grinding coming from the rear of the bike. Any of you run into this problem? I have seen a similar issue on other banshees when the chain is too loose. The bikes only do it under full load from a dead stop.
I have a 100+ hp banshee with a +8 swinger. The chain is in adjustment. It does it from a second gear launch and when the bike shifts to third. It sounds like the bearings are toast in the carrier or the chain is skipping teeth on the rear sprocket.
Could the bearings just be binding on the carrier? (No play in bearings)
The bike doesn't do it in 4th and up. It also won't do it in 1st through 3rd if the load is reduced.
If it is chain related, then could a chain tensioner help?

Mailman

Sounds like the chain is ratcheting. It won't do it in first because it is too much wheel speed and blows the tires away.

Suspended bike or rigid? Fix...tighten chain.

If it is a carrier bearing, you'll hear/feel it when you spin the axle.

[Fouledout421]

Possible motor twisting in the chassis?

[dajogejr]

Fouledout421, on 26 October 2009 - 03:17 AM, said:

Possible motor twisting in the chassis?

That's what I was thinking...
If the motor is twisting in the frame, if a bushing is bad/worn, this could happen.
Many of us run an engine stay or engine "strut" to keep this from happening.

The bike could have the chain tightened perfectly, but if you torque the motor from a hard launch, this can and will happen.

We use a small threaded rod with heims on either end mounted to the frame and motor to prevent this.

[BBIII]

Are you running all the little round bushing's on your motor mounts?

[bubba297]

Anything over a mild build should have 4 of the spacers in the engine mounts. If the engine isnt twisting, then the swing arm is going over centerline and loosening the chain.

[kubitza123]

Are you running a lockup? If so i have had mine when i didn't have enough weight on it, feel like the chain was jumping teeth but in fact was the clutch.

[Performance ATV]

Exactly Mark,mine did the same thing from not enough lockup weight.The clutch is slipping and popping the chain.

[1700camaro]

kubitza123, on 26 October 2009 - 05:10 AM, said:

Are you running a lockup? If so i have had mine when i didn't have enough weight on it, feel like the chain was jumping teeth but in fact was the clutch.

Clutch chatter will make that sound also. Not saying that's the problem, but it could be.

[HartleRacing]

if it is indeed the motor twisting in the frame.. do what i did and ditch the little mounts that go beneath the motor that bolt to the bottom of the motor.. i put in a solid bar that runs the width of the chassis directly below those bolt holes and the motor bolts to that bar.. keeps the motor virtually solid in the frame and strengthens the frame at the same time

[2001Stroker]

Make sure your sprocket hub isn't skipping splines too. I just had that happen to me.

[badassbanshee479]

my 4 mill cub was doing this when it had a broken clutch fiber in the clutch basket.....

[Koolguyson]

Grab the chain, top and bottom with one hand. Squeeze them together and tell us how much the motor moves in the chassis.

[Mailman]

Wow! Some great responses. They all seem like they could be the problem. Here are some facts on the bike. See if any of this catches your eye. I really appreciate all the help.

Lonestar chasis (banshee geometry) suspended
4 rubber spacers on motor
Slingshot lockout clutch with 1 row of balls
Chain is tight enough (maybe a little on the too tight side which usually cures this issue)
I just put the build together so I know the clutch fibers are good (bike did this before the teardown)
When I grab and squeeze the chain, the motor moves about 1 mm.
I still dune the bike so I would like to stay away from a solid mount if possible. I am afraid the frame would start cracking eventually.
Would a chain tensioner help this problem?

Dave, can you post a pic of the strut? Where on the frame do you mount the strut?

Mailman

[Mailman]

Here are the results of the problem: I hate it when people don't post the results.


I fixed the problem.
Basically I tried to cover all the bases and I solved the problem in the process. My spocket had some wear on it to the point that the teeth were starting to bend so I put a new sprocket on. I also installed a chain tensioner. Third, I moved the chain guide real close to the rear sprocket like you would see on a dirt bike.
The combo of those 3 things solved the problem. I honestly don't know which one did it or if it was more than one issue. At this point, I am just glad it is fixed. I have no more chain issues at all!



Mailman

[camatv]

DO not go to solid motor mounts. unless your just track racing and NOTHING else you try fizes the issue. sounds to me like the WORN OUT rear sproket was the problem..

what kind of "tensioner" did you use. if it has one wheel on it and is the goofy spring loaded one TAKE IT OFF and at least put 2 wheels on it all the way across the area. OR send it back and leave it off. if you catch a rut and the rear of the bike whips sideways the tensioner will catch the chain on the side of the wheel and YANK it off and throw the chain..

i really like the engine strut or tensioner. you can preload the engine just a lil bit and as it tq's in the frame it will just pull everything into line.. ( free HP)..

[Sheefreak]

dajogejr, on 26 October 2009 - 03:20 AM, said:

That's what I was thinking...
If the motor is twisting in the frame, if a bushing is bad/worn, this could happen.
Many of us run an engine stay or engine "strut" to keep this from happening.

The bike could have the chain tightened perfectly, but if you torque the motor from a hard launch, this can and will happen.

We use a small threaded rod with heims on either end mounted to the frame and motor to prevent this.

I would bet this is your problem and the chain tensioner helped it. I have seen this same problem w/multiple frames and the "stay" or strut always fixes the
problem. I have a hard time believing your motor only moves a mm when you squeeze the chain. Did you give it a good squeeze, or just put a little tension on it?

[WINDYCITYJOHN400]

Sheefreak, on 04 February 2010 - 05:15 PM, said:

I would bet this is your problem and the chain tensioner helped it. I have seen this same problem w/multiple frames and the "stay" or strut always fixes the
problem. I have a hard time believing your motor only moves a mm when you squeeze the chain. Did you give it a good squeeze, or just put a little tension on it?

Somebody post a pic of your strut/stay device. If I had one I wouldn't eat up aluminum sprockets so fast. LOL.

[Sheefreak]

WINDYCITYJOHN400, on 04 February 2010 - 05:27 PM, said:

Somebody post a pic of your strut/stay device. If I had one I wouldn't eat up aluminum sprockets so fast. LOL.

I will take a few pics in just a little bit after the kids go to bed. I know Tyson builds all his frames w/a bracket for the stay, I am sue many others do. I am not sure if it is much of an issue on rigids w/all the extra bracing etc.

[Mailman]

camatv, on 04 February 2010 - 04:43 PM, said:

DO not go to solid motor mounts. unless your just track racing and NOTHING else you try fizes the issue. sounds to me like the WORN OUT rear sproket was the problem..

what kind of "tensioner" did you use. if it has one wheel on it and is the goofy spring loaded one TAKE IT OFF and at least put 2 wheels on it all the way across the area. OR send it back and leave it off. if you catch a rut and the rear of the bike whips sideways the tensioner will catch the chain on the side of the wheel and YANK it off and throw the chain..

i really like the engine strut or tensioner. you can preload the engine just a lil bit and as it tq's in the frame it will just pull everything into line.. ( free HP)..

I got the tensioner from John at Sandtoyz. I asked his opinion and because I am running a Lonestar frame, he said the tensioner was a must! His tensioners have 2 wheels.
I am sort of forced to run it due to a poor design of the lower roller bracket on the LS frame. It is simply a flat piece of metal welded on at a 90 degree angle with no lateral support. I broke off the tab once and it tore part of the chromoly frame with it so I decided to weld it back on to plug the hole but not to run the roller there. Now I am sort of forced to run the chain tensioner to replace the lower roller. I already have a few hours on the bike and no issues.

On the chain squeeze: I grabbed it really hard and the motor didn't move much at all. I am running the 4 rubber washers instead of the 2 that come stock on the motor.

I guess nobody is giving me credit for moving the chain guide closer to the rear sprocket so it can't lift the chain off when there is slack in it. When you get a chance, look at the location of the rear chain guide on a CRF450 or any newer dirt bike and you will see what I mean.

I may get a bug in my boots and try to figure out what was the magic solution some day but for now it is fun seeing people try to guess. LOL



Mailman