I think my 400 is losing power. Tranny wise, not engine wise. In the mud the other day, it just wasn't what it used to be. It used to be able to spin my mudlites in the thickest mud (not like a 700, but it certainly could get by). Now, it only spins them a little.

While riding, I came across someone who knew a lot more than me and does the pulling at the the fairs with his sp800. He told me that for the 500's and 800's, an EPI HD Black spring on the secondary is the way to go. He said probably same deal for the 400. he said maybe lose 1-2mph on the top end, but gain back a lot of the low end. ( I top out about 41-43 as I am right now).

I know very little about belt tranny's. I looked at mine the other day. With a caliper, my belt is above the service manual's cutoff for replacement width. However, my belt has plenty of slack in it (it displaces a bit more than 2 inches from a straight line between the two clutches.) The guy told me that his 800 is stretched tight, he said he's never seen one loose before. (He also machines his own wheels and clutch shims, so I know he's on a different level than me).

So my question: would an EPI HD Black secondary spring do me much good? How hard is it to install? Any special tools? How much money? I know that my 400 is not a high power engine, but I know that it isn't running at it's potential.

With a full throttle takeoff from a stop, in Hi, it does the following:

Engine revs up
starts to move
engine bogs for about .5 to 1 second
then accelerates (but slowly enough not to spin the tires in 2wd on dirt)

Any insight from those who know more than me?

Thank you
Tyler

 

might be your secondary chutch buttons wore out.. i would recomend a clutch kit , i have a heelclicker and a dalton big foot clutch and i like the dalton MUCH BETTER!!!.

 

change the clip position in the top of the carburetor, go down a notch, see what it does then about the bog. the buttons maybe worn out in the secondary clutch, check them as well