Yes, get a twist.

Actually if you searched you probably found that many yfz owners cut the spring, and others replace it with a thumb throttle from a honda 400ex or similar.

 

Just take the stupid spring out of the throttle cover assembly. There is a huge return spring on the carb so this is not needed and removing it makes throttle pull a lot easier.

 

Don't cut the spring. Do this mod, it sounds complicated but isn't bad. All you need to do, is pull the carb off the quad (easier to work with), pull off the TPS side cover, then pull off the top cover (says FCR on it). Once you have all that removed, you will find a nut on the TPS side of the carb, I think it is 14MM, remove that, and keep track of the nut and washer so you don't loose them. Then, you will need to go on top of the carb (where you took off the top cover) and you will see a screw that attaches the throttle linkage to the throttle slide (its a Phillips head), unscrew that. Once you've unscrewed that, then you'll need to go to the side of the carb where the throttle cable goes into, remove the cover, then, carefully pull out the throttle linkage, make sure the slide doesn’t fall out the top of the carb or you'll have fun chasing the tiny little wheel things that are on it, while pulling out, make sure to keep track of the two thin washers, as those like to fall out (they're on both sides of the throttle linkage inside the carb). Once you pull out the throttle linkage, you'll see the return spring, attached to the linkage. That spring attaches to a groove on the throttle body. Now once you have located the spring, and the tab that the spring connects too, you will see another tab on the throttle body. What you will need to do, is drill a hole, or cut a new groove on the tab (that had no groove that was unused before). Once you've cut the new tab, attach the spring to the new groove; double-check to make sure it's secure. Now, just reverse the steps you took in disassembling the quad, and reassemble it.

THere is a link with pictures somewhere, If I can find it I will post it.

 

Does that really work???..... Barelylegal?

 

I just put on a Cascade lever, But you basically have three choices, modify the return springs, put a whole new assembly on(like the 400EX one or a twist) or buy a new throttle lever/extender. BTW, that Cascade extender was one of the best $40.00 I've spent on my quad!