Hi,
my Suzuki Ozark has good midrange but when you get into the top end it falls flat on its face. It revs up high and sounds healthy but there is just no power.
It still gains speed, just not nearly as quickly as it should.
The carb is o.k., I suppose it is not a jetting issue...

Any ideas?
Thanks!

 

So are you saying that the quad has changed or has it always been this way? In other words, are you complaining about the lack of power from a 250 in general or are you saying that it used to have power and now all of a sudden you have no power? How old is the quad? How long have you had it?

 

Hi, I have had it for 2 years (K6). I would say the quad has not changed. There has been always lack of power on top end, but I thought it was normal. But last month I was riding on a rented Ozark which was much better than mine. Since than I tried some other Ozarks and realized that mine is really weak on top end. Meanwhile I had some problems with bad gas (popping, stalling) but it was definitely solved (drained carb and tank, adjusted Air/Fuel screw etc) so this is something else. I suspect it is the Ignition Coil (No. 5) as almost all other possible causes were checked.

Service Manual:
Engine runs poorly in high speed range
1. Valve springs wakened. Adjust.
2. Valve timing out of adjustment. Replace.
3. Worn cams or rocker arms. Adjust.
4. Spark plug gap too narrow. Replace.
5. Defective ignition coil. Adjust.
6. Float-chamber fuel level tool law. Clean.
7. Clogged air cleaner element. Clean and prime.
8. Clogged fuel pipe, resulting in inadequate fu el supply to carburetor. Replace.

Thank you!