Let's say you have two 400exs.

One of them has a 440 (bore) and the other is a 440 stroke. Will the bored 440 have more top end becaue it revs higher and the same low end as a stock 400ex and will the 440 stroke have just more bottom end and same top end as stock?

 

Take for instince a Chevy 302, 4.000 bore and 3.000 stroke, and a Chevy 305 3.730 bore and 3.480 stroke.
The 302 will rev to the moon were the 305 will be done at about 4500 RPM. The 302 will make a ton more HP while the 305 will make more torque at the lower RPMs, however the 302 will surpass the 305 in torque at a higher RPM you catch my drift, the 302 has a lower rotating mass due to the shorter stroke which will make it spin faster and free.

 

I had a '99 warrior some years ago. On a paved road with the stock tires and an aftermarket silencer/intake/jets, it could float the valves in sixth. It would take a ways to get up to that speed, but once you hit the max, it was over. Soon after that, I changed to 20" bandits on the rear and a 15 tooth front sproket. With a friends GPS, I clocked myself at 65.4 mph on asphalt. With the same gearing and 22" tires with the engine mods, I would guess that a warrior could easily get into the low 70's.

 

Call FST they'll fix the valve float problem with heaver springs, I got them there easy to install too.

 

The valve float problem was minimal, with my current bike, I don't have to worry about it anymore (no valvesprings).

 

The whole point of the thread is -- gear down in front or up in back for acceleration and gear up in front or down in back for top speed...

 

The only way a warrior is "easily" getting into the low 70's is downhill or in the back of a truck/on a trailer. Best I've pulled on a slight downgrade with stock gearing 13/40 and 22" razr's was 109.9km/h according to my trailtech. And even that took a while to get to. If you were bored to a 435 you could possibly "easily" get to low 70's .. The stock warrior has gearing to get over 70 I'm sure .. but it doesn't have the power. It used to take me forever to get up over 100km/h with the 13/40 gearing. I stepped down to 12/40 and I get to over 100 much quicker now.

The only rev limiter a warrior has is it's weak valve springs [img]i/expressions/face-icon-small-smile.gif[/img] like others have said, the valves begin to float in the higher rpm ranges .. if you stiffen those up you can probably squeeze a bit more out of a Warrior.

 

anyone want to let me in on the term "float the valves"

 

Ok, there is a simple way of deciding this. Assuming that your trail tech was installed correctly and using a simple 5/8 rule for converting kilo into mph as in the original post your 109.9 kph is around 68.6875 mph. That is as you said with 22" razr's that are heavier than the stock tires and therefore increasing the rotating mass of the atv, which slows it down. A slight downhill will also affect the speed, but I averaged around 64 mph both uphill and down so that is negligible. The stock warriors hp is not really a concern in top speed runs, as there are land speed racers with less than 50cc running over 70 mph easily. The warrior can easliy pull higher or lower gearing, all personal preference. With a 13/40 the warrior has a gear ratio of 3.07 with 15/40 it is a 2.67. That is a big difference! In a street application that would be the difference of running 2000 rpms or 1200 rpms at highway speeds. With extra room to stretch it's legs, the warrior can easily run over 70. If the trailtech says it can run 68.6875 with stock gearing and heavier tires, then with a pipe, intake and gearing 72-73 should be easy, without the 435 kit, you just have plenty of room to get to those speeds. With the reduced mechanical advantage from the higher (numerically lower) gears it will take lots of room and be a serious strain on the engine.
Also valve float is the rebound of the valve bouncing off the seat and staying there. The valve springs don't have the pressure needed to force the valve closed and often destroying the engine can result. Just ask someone that races circle track!

 

Which is why I said "easily" ... if you need 3 miles to get up to 70mph, then that's not what I would consider as "easy" Easily getting up to 70mph for me would be in well under a mile. When I topped off at 109.9km/h, that was probably around 800 or 900m to get up to that, and that's with the down grade. I didn't consider that an easily acheivable speed for my Warrior. The only real mod I had at that point was the FMF slipon. With proper jetting and airbox mod I'm not sure what would happen. I do know that with the new 12/40 gearing my accelleration is heaps improved, but I doubt I would reach 110km/h again .. I've hit 102.2km/h since installing the new gearing, but no faster.

Floating the valves means (someone correct me if I'm wrong here) that the valves are not fully opening/closing as they should which means your compression stroke is not as strong as it should be and your intake/exhaust strokes are also suffering. This robs the power from your engine, preventing you from going to any higher RPM's. Stiffer springs will force the valves closed, thus keeping things going the way they aught to.