OK, I am in the process of trying to figure out why a friends scrambler 400 4x4 feels slow.
Checked the basics, had good compression, fluids are good, changed spark plug....

Now, I also have a 94 Sport 400 that I have been using to compare some things.
I pulled off the clutch cover on both machines. The belts appear the same, but on the scrambler, there is a lot more play on the belt... even when I take the belt from the other machine and try it on this machine.
Also, I can push very hard on the 94 sport belt and the driven clutch does not seem to seperate.
On the scrambler, it takes almost no effort whatsoever to get the 2 halves to pull apart from each other. Once they are seperated, the halves will not come back together until I spin the driven clutch by hand a full turn or so. Is this normal??

I am going to get a new fuel filter and clean the carb out tomorrow I hope, get everything else in good shape to make sure I'm not missing something simple.
It just seems wierd to me that there is this much play (probably 2-3 inches of deflection), and that I can push on the belt enough to make the driven clutch completely open and make the top of the belt touch the bottom of the belt with not too much effort.

Any tips would be appreciated, just want to get this thing running how it should be again... in its current state, my 300 Xplorer would outrun it! [img]i/expressions/face-icon-small-smile.gif[/img]

Thanks,
-Chris

 

Broken driven spring or helix buttons, or broken helix, or shieves.
Take driven clutch apart and check it out!

 

you probably have too much shims in the secondary,
belt deflection is 1" 1/8 to 1/4 but,some very modded engine will need
only 1",remember the primary sheaves clearences is .020.
so you must be sure center to center distance is 10" and the belt fit
on the straight edge/faces of the sheaves.
remove some shims to pull the belt out on top of secondary...

 

It sounds like someone wound the rear clutch incorrectly when they re-installed it. That will cause the bellt to not have any tension on it and it will run like crap.

 

Sound like the secondary buttons are shot, how many miles are on this quad? If the buttons are bad that could be the problem with the belt deflection as well the sheaves could not be closing all of the way due to the buttons being shot. If you inspect it and see that the buttons are good double check c/c, adn secondary shims. Does this quad have a cluthc kit or anything else in it? 90% sure on the buttons though seen it 1000 times over to prevent it go with a team secondary, note riding in rough terrain has been shown to make these problems occur more often.

 

OK, I will pull the driven clutch off tonight.
Any special tips on taking it off? Special tools?

I am not sure on how many miles on the ATV (no gauges)... it is currently used very little as more of a hunting ATV by an older person. I do not however know who the previous owners were and how they rode it.
The machine is in good physical condition, however the rims have seen some hell, so I would assume it has gone through some tough terrain, heh.

I will let you know what I find when I pull off the driven.

Thanks,
-Chris

 

Driven should come off but you might need apuller if its stuck, which tends to happen if they havn't been of in years.

 

Well I pulled the driven off today.
Well... it's not pretty.

I first noticed when I tipped it, I heard a clank
got the snap ring off, one of the buttons looks to have been put in with a regular wood screw and it ripped right out of the helix.
The helix was gouged and one piece was slightly damaged.
I put in a driven clutch from a friends 400 sport and it works great.
The ATV still seems to bog down low, but once it's moving it has tons of power... thinking it might be jetted wrong or something... will pull carb this weekend.
Well, I will probably order up an HPD unit, as its way cheaper than a new polaris part [img]i/expressions/face-icon-small-smile.gif[/img]

Thanks,
-Chris

 

One more thing to check if the jetting doesn't take care of the bog is belt deflection we see this get over looked over and over again and 50% of the tie they aren't right from the factory.

 

OK, I ordered a used secondary off of ebay and just got it today. Friend just wanted a stock replacement for now.
Opened it up because I figured the buttons would need replacing and they do. The helix is in good shape, minor wear, nothing bad.

The thing is, it has a white spring in it. The original had a red spring in it.
When I look up what it should have, I see it should have a red spring... I am guessing this came from a machine with a shift kit.
Should I use the original red spring or the white spring?
Also, what spring setting should I use? The original was 2 on helix, middle on clutch. This was 2 on helix, far right on clutch.

Thanks,
-Chris