I took my new SC400 out for its first real ride tonite and everything was going great until I got into some deep mud about 3/4 of the way over the rear tires,When I gunned it to push through the stuff the chain started "slapping"? and and raiseing all kinds of hell when I went over half throtle,It made a vibrating pulse on the right floorboard!! With the bike setting in the mud the chain maybe had a 1/16 deflection maybe, But with the bike out of the mud & in the back of my truck it had about a 1/2 inch what gives has his happened to any one else??

 

A friend of mine's 325 TBoss did the same thing when it was new. I think it is because the new chain was tight and the mud gets between the rollers on the chain and the sprockets and takes up all the slack in return stretching it.

 

The exact same happened to a sport and scrambler in my group(both brand new).We were spinning our way through some sand piles and all hell broke loose.The scrambler managed to crack the case the front sprocket rides in.Oil was dripping,dealer didnt cover it(abuse), so we tore it apart,had it welded.The only thing we found to fix it ,is to run that chain super tight.I know that sounds crazy but both the chains have performed perfect with about 1/8 of slack.We thought that the frame must flex or something.When it slapped in the sand we got off ,and like you said their was 0/0 inch of play.Back on the road all was ok.Try running that chain tighter.even though it goes against everything I know about chains

 

There is an aftermarket company that makes a specific chain tensioner just for the scrambler.
My experience with the scrambler has been the same. If you run the chain too tight, you will snap it jumping, and run it loose and all hell breaks loose in the mud. I also have thrown the chain and craked the case on the scrambler. I will try to find out the name of the aftermarket company for you. I have around here somewhere.

 

The diagnosis from the previous posters is bang on. I drive a SP500 so have no direct experience with an ATV doing this.

However, my bulldozer does the same thing! The tracks are simply 2 large chains with pads bolted to them. When I get into mud or even just sand, there is a noticable difference in tension. You would think the sand would simply get forced out of the way but it doesn't.

Cowman, overtightening chains also goes against all of my experience with chains (on other equipment)! To me overtight = chain wear/breakage, gear housing problems, bearing problems, crunching sounds, extra load on the engine, etc.

Everyone has their reasons, but shaft drive was one of the selling features of the SP for me.

Surely there is a spring loaded chain tensioner (or equiv.) that will help with the situation? Maybe the unit 88blaster is talking about?

DJ

 

I talked to my dealer today and he said with concentric drive to run a MAX of 1/4 inch deflection with the bike setting on level ground and not to worry,In the day light my chain looks like it might be over a 1/2 inch im not sure but it will be changed tonite!!