I've got a 98 300ex with a 380 big bore kit with all the goodies up top - oversize valves, port & polish etc... I have no problems with the engine - has a ton of torque, it loses a little bit on the top compared to the 330 kit I had before but it is a low end monster for a small quad. My problem is with the clutch. I've burnt up three sets of fibers and two sets of steels, tried a zillion spring combinations and now have a DP heavy duty kit in it and it slips worse than the burnt one I removed. I did use the springs that came with the DP kit and they were softer than what I had in there, but I thought I would use the kit as a whole. The best spring setup I tried was heavy duty 350X springs shimmed with a couple of washers behind.-----Here are my questions, there are quads making twice as much horsepower as me, why am I having trouble with slipping? The basket and pressure plate are stock and in great shape, do they need to be replaced? I know the Hinson basket has holes in the fins for better cooling, but my slips just as bad cold as it does hot. It hooks great on the holeshot, through second and sometimes even third. It slips mostly around forth and a bogged down third, on the TT track, coming out of a medium sweeper nailing it for the straightaway, it slips for a hundred feet or better.
Any help would be appreciated, I'm about ready to pull my hair out. I would buy a whole new aftermarket basket and plate if I thought that would help, but I don't understand how it could be anything other than the fiber, steel and spring components.

Thanks for any help you can give.

 

I had a set of springs made by Boker (company that just makes springs) for my 250x motor (alky 410cc). They worked great. I ran a barnett clutch kit when it was a 352 on alky and it held fine though.

 

What oil did you run? I'm beginning to think that might be my problem. I run Castrol 20W50, as suggested by my engine builder.

 

I ran a 352 kit for 5 years on the stock clutch and a 406 kit with the barnett clutch plates and springs after that and never had it slip or wear out ever. Hows your free play? Synthetic oil? If you want to try my old set up Ill sell it to ya cheap. You can have the whole assembly.

 

Castrol 20-50 here also. I ran the castrol V-twin streetbike oil though. I ran with Energy Release mixed in. I think I mixed 2 ounces per quart of oil.

Who's your engine builder?

 

ProFab ATV in Ohio. I think he is doing something else now, his website is down and I haven't heard from him in a while. I was very happy with his work.

What is energy release?

 

i have a 99 300ex and im wondering what size bore kit to get and how much would it cost.
thanks[img]i/expressions/face-icon-small-smile.gif[/img]

 

Hi My Name is John Madison I also Own a 300ex i was wondering where you would get a 330 big bore kit, and who would be the best to install it (dealer or?) thanks for your times
my email is jmadison322@homtmail.com