Jetting question

[Major]

I have a 06 Grizz 660 I just put on the KN filter and a DR.D pipe. I have a Dyno jet kit ready but so far from looking at the plug it is still a bit rich. I ran a WOT and hit the kill switch. got stopped and pulled the plug. The strap is light grey and clean and the base of the plug (where the threads end) is slightly black with light soot looking stuff evenly deposited on it. I have not noticed and lack of power or anything through out the power band. I ride mostly in the RockyMountain house area (Prarie Creek and area) Should I need the jet kit installed??
Thanks

 

[DaveB]

My experience with jet kits over the years is they really aren't needed for us Alberta guys. All our machines are jetted to be safe at sea level...stick a pipe and a free-flow air filter on em, and they are nearly always still safe for riding 3000' and higher....which is most of Alberta.

 

[Absolute Power]

My experience with jet kits over the years is they really aren't needed for us Alberta guys. All our machines are jetted to be safe at sea level...stick a pipe and a free-flow air filter on em, and they are nearly always still safe for riding 3000' and higher....which is most of Alberta.

This is partly true. Most quads are safe to install intakes and pipes on without jetting but with a properly set up "Jet Kit" the slide spring is shorter or a weeker spring is provided giving a quicker responce to the slide, hence increasing midrange acceleration, as well the "Jet Kit" should have a smaller needle to accomadate the increased air due to the slide opening sooner. So the question still remains are "Jet Kits" required. The answer is yes, a properly set up machine will have increased acceleration and power due to the above.Welcome to Absolute Power

 

[leonard]

If the plug looks clean at WOT then its probably ok main jet wise.

Id probably still open it up and at least replace the spring for better response.

you should probably still do stops at 1/2 and 1/4 throttle to find out if your needle or your pilot need to be changed.

running slightly lean isn't a bad thing either in a 4stroke it keeps the engine cooler aswell. you just don't want to have it too lean and foul plugs up ect.