Hi all.. new member here. I have inherited 4 busted up atv through my fiance's late husband and kids. They thoroughly beat the crap out of two brand new Kawi KFX90 which I finally got running well, a 99 Scrambler 400L 4x4 which I've not seen run in 4 years, and today's reason for posting... A 98 Sport 400L 4x2. The pair of 400s came here third hand from someone who fancied himself as a mechanic. Aka, he rigged the hell out of them for more "speed", and royally screwed them up. The sport has sat for the last 4 years, but showed the most promise so I began fixing and replacing from the battery and so on. I work at a lawn and power equipment shop, but we don't specialize in quads, so this has us stumped. To date, we have replaced the battery, starter and solenoid, key switch, carburetor, drained and flushed the oil and fuel tanks, all filters, new fuel line, new piston and rings because of severe blow by and scoring. Cylinder walls were solid. All new gasket set. Connecting rod, crank and seals were in great shape. Bled the coolant to get air out of the system. Put all back together, and she fires right away. Idles incredibly well. Problem is now it won't move forward or back. So off comes the clutch cover. Replaced the belt, that helped a little.. as in it at least lurched a bit when hitting throttle. But for whatever reason, giving it any throttle makes it fall flat on it's face. Usually backfires, and my little kawis rev up higher and better than this thing. We've tried tuning this carb 90 ways from Sunday and just not luck. With basically rebuilding this entire machine, I'm hitting a wall and can't figure it out. Any suggestions? Thanks, and sorry for the long story, but I felt all the detail was necessary.
