Need help jetting?????????

[shaneohio21]

I just need to know a ball park number here are the parts and what i have done

Stage 1 hot cam -- Ported and polished head----Uni air filter--- Air box cover off--- hmf slip on exhaust---new intake valves

I know its best to just put a load on it and keep checking the plug but i know there r people out there that are dead on without checking it every time

[bigd's ex]

Welcome to the " ADDICTION ". Not trying to be a smart*****, but if there's someone that can jet a bike right the 1st time all the time, we would all like to meet him. Even though you might have the same setup as someone else does'nt mean they will be jetted the same. Every bike is different. It's pretty much trial & error at 1st . Weather & elevation also play apart in jetting. Do yourself a big favor & read some of the threads on jetting , there're full of info & will help you out a bunch. The guys on here really know their stuff. GOOD LUCK !!!!!!!!!!!!!!!!!!! :macho

[Newrider08]

I can get it jetted rich but not perfect, start with a 42 pilot ( maybe a 45 if that if you have to back the air fuel screw out more than 3 times )

A 170 main might be a good start, take that out for a spin and if its smoking or running crappy try going down a size in mains until it runs how you think it should.

This is a relentless process and you will eventually get it right ( until it gets cold again lol ) , Keep logs of the jets you put in to make it run right and what the ambient temp was.

I did that on my two stroke quads and any time I felt the quad not quite acting right I would look at that and see that a #** pilot and a #*** main jet were perfect at 58 degrees and on a 62 degree day its close enough and that really helped me, no im trying to figure out the whole four stroke jetting but im getting the hang of it


jets r us might be a good place to visit, you can get a main jet kit with a bunch of various mains for like 29 bucks and that way you can experiment without going to the shop every time you need a jet


http://www.jetsrus.com/a_jet_kit_atv/honda_400_TRX400ex.htm

[rinaldi]

Is there a thread that shows "how to" re-jett? I am reading on which jets to start with but still am unsure where to install or how to tear the atv down to install the jetts.

[bigd's ex]

http://www.atvriders.com/articles/pilotjet.html

Hope this helps !!!!!

[rinaldi]

Wow that seems to be time consuming. What is the avg time to tear it down? Thanks for the link.


Originally posted by rinaldi
Is there a thread that shows "how to" re-jett? I am reading on which jets to start with but still am unsure where to install or how to tear the atv down to install the jetts.

[Newrider08]

I take off my back fenders and seat which is VERY easy, just pull the latch under the seat, then you can take off your airbox with the bolt or bolts holding it, then I take the breather tube off the engine under the carb and take the whole airbox assembly off. This gives me more room to move, then i just loosen the clamp that holds the carb to the engine. If you are on the left side of the quad you can just pull the carb out of the rubber boot and turn the bottom toward you ( be careful not to twist the throttle cable ) then you just take off the float bowl and rejet with the new jets.

It is easy to do and after you do it once its a breeze. I dont even take off my front fenders, just the side skirts

[bigd's ex]

It will be at first, but after you do it a couple of times & and discover your own shortcuts it's not as bad as it sounds. If i'm changing a pilot jet I'll take the carb completely out to work on it, if it's just a main, I roll it enough to get to the 17mm cap on the bottom of the bowl to get to the main jet with a 6mm socket. You still have to break down some, remove tank & snorkel, but it sure beats taking everthing apart. :macho