98 yzf 400

Joined
Jun 10, 2007
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#1
i just bought a yzf 400 and it doesnt even compare to my 250 2 smoke is there any perfomance products i can get to make this bike as fast as the newer 450s also it seems like the clutch is slipping at high rpms in 5th gear is this a problem in thses models or is it somthin in the bottom end.
 
Joined
Jan 27, 2000
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#2
yz250rider1 said:
i just bought a yzf 400 and it doesnt even compare to my 250 2 smoke is there any perfomance products i can get to make this bike as fast as the newer 450s also it seems like the clutch is slipping at high rpms in 5th gear is this a problem in thses models or is it somthin in the bottom end.

The 98 yz400f was the first year for Yamaha's modern thumper engines. Many changes have been made to this engine since it first came out. If you want to make it faster like the new 450's you will have to go to a big bore with a high compression piston and a cam would help.. Remember, there is no replacement for displacement. ;)

If the clutch is slipping you will have to adjust it. If adjusting it doesn't help, you will have to replace your clutch plates. Refer to your manual for this. If you don't have a manual, get one. :cool:
 
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Jul 16, 2007
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#3
That bike is about 10 years old. Yamaha has made many upgrades to the 426's, and now, to the 450's. They make some type of progress every year. So to want your 400F to compete with a 450F, you're going to need to up-grade her. I think they make some big bore kit for it, and it'll add a bit more compression, if that's what you're looking for. I believe this is a bit costly, but if it's what you want, then it must be worth it.

And if that's the stock clutch, and it's just now slipping, that clutch held up great.

Also, since you bought it used, you should completely go through the bike. Make her like new, especially if you're going to throw money at her. Check the valves, carb, always keep up with the chain and sprocket. Re-jet her if you need to.

This is just my suggestion... Take it with a grain of salt if you will. I wish you the best of luck with getting the performance you're looking for out of the bike! Let us know how it goes!

- Heather