Ive got an 01 400ex and I have heard some sketchy information that riding wheelies on some atv's may cause oil starvation problems when the machine is upright. I know that this would depend on the location of the oil pick up in the motor, i.e. front or back. My question is, with a dry sump system like the 400 or the raptor, with the external oil resevior, will a wheelie cause any problem at all. I would think not.
Any knowledgable information would be appreciated.

 

In my opinion, the wheelies will not hurt the 400 ex because of the dry sump system. Dry sump systems are used in high performance machines such as Dirt Late Models. One of the primary reasons that they use a dry sump systems is to prevent oil pickup problems during hard acceleration and cornering, whereas the oil in a wet sump system would be forced to the back or side of the oil pan, thus causing pickup problems. The dry sump system should have no trouble with oil pickup during wheelies or hard cornering. Hope this helps.

 

I don't know about the oil, but you will lose gas through the overflow, and or vent as you are wheelying.

 

The dry sump engine still has a sump, and an oil pickup. These are located towards the front of the engine on your 400EX. A dry sump engine still has oiling issues, but it does cool the oil much more efficently than the old, oil in the tranny, way of storing the slick stuff.

Extended wheelies can damage a four stroke engine -- in theory.

For some reason, it doesn't seem to affect them as much as you think it should.

If you are riding wheelies for 1/4 mile or so, you will cause oil starvation, pump cavitation and all sorts of yukky stuff. If this is the case, you'll need to devise an extra oil pickup at the back of the engine -- it's a hassle!

Of course, you could install a separate oiling system for the head, which you turn on just as you start your wheelie....then you'd have to drain the extra oil when you're done...boy, so many ideas, so much time and money to implement them!

This is one reason why Doug Domokos and many other wheelie dudes run two strokes as a rule (or something like the Rotax engine that has the pickup towards the center of the engine).