my sons 04 zr120 seems to really be binding up, you can hear it the worst at slower speeds and on take off, really loud
knocking noise that is proportionate to revolutions of the track. I have installed a rec tensioner, clutch and rear sprocket
in hopes of eliminating this but it seems the same. any input??? I'm about ready to pull the skid and see whats up maybe
with the driveshaft? It seems tight and none of the side bearings on the mainshaft have play but I'm stumped on this one.
The sled does not have a ton of miles either.

Try checking these things first:
Track to tight?
Chain bound up?
Check to see if the brake band is dragging on the clutch.
Remove the chain and spin the track see if it is still binding.

Hope this helps.

I find that the clutch makes a banging noise. its because the motor doesn't have quite enough torque to engage the clutch fast and hard enough so at the beginning of engagement it chatters. this can be verified by guys running a stock style clutch on bigger or more horsepower engines. my sons is the same way as yours till he gets the 6.5 honda upgrade.
i guess that assumes you are talking about the same clunking or banging noise i am...

Good info guys, the clutch is now a rec motors clutch and I do agree they are very noisey.

Shawno, I'm starting to wonder about the track tension, how loose can you run these tracks?
they seem alot harder to get a read on without a front shock in the skid, Is there a rule of thumb
you use or a good starting point?

The track does tighten up in the same spot on every revolution, I believe that is where it is binding
up.

A tough question to answer:
Loose = Fast
Loose = Ratchet
Tight = Slow

It's a tough balance and its trial and error. My oldest son's sled was ratcheting all day at the races but I'll be damned if it wasn't running fast, once it got moving. I will tighten it a little.



There is a tight spot on the chain while turning the track at that spot is where you want 1/4" of play in the chain.

nope, i know what is making the sound he is talking about, look under the track at the top there are two white wheels i am betting one is seized and it is klinkin on the track clips, it looks like a roller skate wheel
i had same problem with my sons sled and it sounds like ratcheting but its not.
check it out
dan

I am having the same problem with my '03 ZR120. It just wont get going and seem as though the track is all bound up and is making terrible noise when trying to go. I have gone both directions with track tension and chain tension. The white wheels are fine in the skid, jackshaft bearings seem fine and when you pick the back of the sled up the track runs fine. Could the driver cog on the jackshaft have moved?? and are binding on the track?? I am desperate for help here !!!!!!! Its really starting to PISS me OFF. The only thing I haven't done is install the extra track clips , but the thing worked fine previously

thanx for any HELP

Yamiblue, I feel your pain,

1st off what clutch are you running, the factory or a gripster clutch?

Here was my delema, my rear sprocket went bad, so I called rec motors, they suggested to switch
to #35 chain and go with a 15 tooth gripster clutch and a 54 tooth rear sprocket and a new tensioner so I
spent the money and then developed a worse noise. Thinking it couldnt be the drive chain since everything
was new I tried several different track tensions and still made the noise, I removed the rear skid and even
replaced the drivers with the 6 tooth from rec motors also. After the 6 tooth drivers were installed, the noise
got even worse!!!!

So I removed the hood from the sled and had my son drive it while I walked beside it, the noise is coming
from the clutch slipping. So I come to find out the engine doesnt have enough power for the gearing I have
installed in the sled. So Ive got $225.00 invested in crap that wont work in the sled. So my choices are up the horsepower
or go back to factory gears and chain. I'm installing the factory front clutch a new rear sprocket and a new #40 chain that the
sled came with. I'm tired of working on it!!!!!! All I wanted was a more dependable setup and got nothing but headaches.

I'm new to mini sleds obviously, but I wouldnt have guessed the clutch could make that much noise. When you observe
the sled running around the yard and clunking like a steamengine it appears the track is really binding up, but in reality its the
clutch slipping in my case.

After the gearing change the sled wouldnt take off if there was any inclines at all, and yes it does have the performance
kit from rec motors installed also. I wouldnt stray from stock gearing if your not going to race it. I'm not thrilled with the information
I got from rec motors as Ive got alot invested in parts, but they were very nice to deal with.

I hope this helps you as I've spent alot of time chasing my tail with this little sled.

I don't know if this will help.
Our gearing set up is simple, stock clutch, 420 chain, Rec motors chain tensioner, Sport tech hub, and a 39 tooth rear sprocket for all around use 42 tooth for tight tracks and 36 tooth for flat tracks.

I am running the recmotors BluePrinted race clutch 15t and went all the way up to a 56 rear sprocket to try and get it to go.
BUT ALAS i think i found my problem !!!!!!!! HURRAY ............. While sitting at my desk and stairing at the clutch and spinning the clutch drum I have discovered that the clutch drum is EGG SHAPED it must have gotten DROPPED at the factory, or damaged durring shipping , i dropped it durring installation OR the kid got stuck in the snow and smoked the thing and it warped the drum. In any case i ordered a new clutch drum and will find out and repost as soon as i get the new drum If this turns out to be the cure i will be one happy SOB !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!