I added an EBS clutch to my '02 - 400 Sportsman, because of all the steep hills in southeast KY. The clutch was ok when I first started using it, but after about 1200 miles, it now seems to be upshifting at a slower speed than it used to. That makes it seem to have lost power, and believe me, the 400 can't stand to lose any power.

Air and gas filters, air intake, plug, valve clearance, brakes, etc. are all ok. The interior of the clutch housing still looks new, and when I took the driven clutch apart, there is no apparent wear on anything. The dealer mechanic verified this. The belt measures 1/1/8" wide, which is right at the bottom of the specs. The length (circumference) is actually just slightly shorter than specs. When I lay it on a table next to a new one, you can just barely see some slight difference in width.

The primary spring is blue/green (green stripe), and the secondary spring is white/red (red stripe). There is no white secondary spring even listed in my service manual chart for the secondary clutch, but then it's actually for the 500 HO EBS clutch.

When I accelerate hard on blacktop, I can hear the clutchs upshifting really fast just past 25 mph, and by the time I reach 30, it just seems like all the power is gone. Eventually, it will reach the upper 40's, but it takes a long time. When it was new, it did a lot better than this. Could a small amount of wear on the belt do this? Could a spring be too weak, or the wrong color? Any ideas?

 

First, the Sportsman 400 weighs 697 lbs. That's heavy. REAL heavy for a 400. Remove the racks, winch, floorboards and the muffler, then take off that sway bar. While you're at it, drain the slime out of your tires, and leave the tool-kit behind. Try to run with 1 gallon of gas instead of 4 that'll save you about 25 lbs. So you'll have to buy an external gas tank to drag behind you on a rope if you want any type of range with your quad. Install a large manual crank handle on the side of the engine so you can manually assist the motor with turning your transmission. Make sure the crank extends out far enough so it won't hit your leg or it'll get pretty awkward in steep/off-camber situations. Set up the crank so that it'll free-spool like a ten speed bike transmission when you're not cranking it, otherwise it'll spin constantly and will certainly be a nuisance. You'll probably would want to put the crank on the left side so your right hand is free for giving it gas and steering. Might want to relocate the master cylinder to the right side as well, that way you can gas, brake, and steer while operating the large crank with your left hand. ...And try not to drag race any other 400 utility quad out there, but if a guy with a 250 or a 300 utiltiy quad wants to race go for it! With the big crank and a 400 cc engine you're bound to win! It just occured to me that since your floorboards are removed you can also get a Fred Finstone type motion going with your feet. That coupled with the manual crank and powerful 425 cc engine, you'll have all the power you'll ever need!

You can look on the bright side though! You're not going to be pulling any sick wh0r3s out of the bed, so your chances of getting V.D. or worse are extremely slim! ;-)

Anyone else have suggestions for restoring the power to TechGuy's quad? I'm out of ideas. :-D He's a good fellow, give us a hand if you can!

 

You need to increase the preload on the secondary. If you don't have a manual, do a search on here for secondary preload or secondary spring and you should find the info you need.