A ds will run on a dead battery.... When my rectifier died out and my battery was dead I had to push start it and it started right up. Push start does work but you should start it in 2nd because first has to much torque.

 

Yes, with the light off on a dead battery the stator will charge it enough to run well push started, but what I'm saying is it wont run without a battery. If you don't believe me try it........

 

i took the head off mine i'd rather carry a extra battery than try to kick that piston over.

 

To kick start a 400cc 4-stroke engine they have to add a compression release; this lowers the compression enough for a human to kick it over. This is what Yamaha did on the YZF400 and 426. (I'm not sure if I got the exact model number right.) These larger bore 4 stroke engines have way too much compression to ever kick over. From what I have heard, the YZF400/426 is nearly impossible to kick over without the compression release engaged. Your best backup for starting is a quick roll down a hill and throw it into second or a drag start from another quad. This is why it is always good to ride in pairs, no matter what ATV your on. If one brakes, the other can tow it back to camp - so long as you've brought something to use as a tow rope.

 

the DS has an auto decompressor - most 4-strokes do, and always have.
It will not run with a dead battery. a lot of quads are the same way - it takes juice to make juice.

 

I recently got a 2002 426F. You can't even start that thing from a roll. Way too much compression. Hightower is right, there is an autodecompressor on the ds (exhaust cam if I remember right). At slow rpms (engine not running) it hits one of the valves and opens it up - releasing the compression - once the engine is started the RPM's cause the centrifugal force to pull the weght up and out of the way so it won't open the valve.

I hear Yammy put an autodecompressor on their new 450F but, I recently saw one at a dealer and it still had a de-compressor pull - (maybe they had last years model on the floor or something - didn't look too close.) Oh, don't try starting one of these without using the compression release to get you past TDC, I am 220 and the engine won't move a bit. Way too much compression in these things.

2nd gear starts in the DS are easy. I do it all the time if I am stopped on a hill. Wouldn't want to have to push it though.