Jetting help? So confused

[Drifterboy3]

Hey guys I know there are a lot of posts on this but I'm confused on which way to go. I currently have a K&N filter no lid stock header with no muffler and a 11:1 piston if it matters What would you suggest to go with for main jet. When I replace it I am going to get a 42 pilot to help with winter starting. Thanks for the help.

[BlasterEaten250]

No muffler? Assuming you mean the stock exhaust, a 150 main will be fine for just a K&N and no lid.

[Stickman400]

I think I'd try a 160 with that 11:1 piston and see if it will fully rev out, if it doesn't then go with a 155.

[Honda5]

150 main at the most. You don't need more fuel because of a higher compression piston.

[Drifterboy3]

By no muffler I mean litterally nothing just the header

[Honda5]

Wow forget what I posted. Good luck with that.

[JOHNDOE83]

Originally posted by Drifterboy3
By no muffler I mean litterally nothing just the header

Thats how I run and tune mine at the drag strip for the most power, speed and acceleration.

The only way to tune a 4 stroke properly is to use the www.jetsrus.com method for tunning main jet, go to the link then go to the FAQ section under how to re-jet, then look for main jet.

Plug reading is irrelevant.

[on the rocks]

whaaaaaaaaaaaaaaaaaaaaat? people actually run them with out a muffler? lol

let me tell you back pressure is sooooo over rated these days...

[BlasterEaten250]

Originally posted by Drifterboy3
By no muffler I mean litterally nothing just the header Are you drag racing?

[Drifterboy3]

No trails at Haspen acres. I bought the quad from a guy that epoxyed the end cap on and the bolts are stripped so I can't get baffles out. And I can't afford a new system yet and I hate the way it sounds with stock on there. So I took it off and said screw it

[Stickman400]

You can't remove the baffles from a stock exhaust, they are welded into the canister. If the exhaust is in one piece and usable I would put it back on there, doesn't matter if you don't like the sound of it, it will hurt your exhaust vavles over time by having no back pressure on them.

[CJM]

Hold on there knuckle head. Go take that muffler and put it back on for now.

Running without a muffler is a very bad idea. This isnt a car, it needs the back pressure to run properly unless your drag racing it. It will damage the valves which cost WAY more to fix than buying even a slip on used.

I bet you ten bucks you can find a nice slip on on the classifieds forum here anyways. For less than 100 bucks too.

[JOHNDOE83]

Ok, I agree with everyone that unless he's drag racing he really need's a slipon or the stock muffler, not because of the valve issue but more for the sake of your neighbor's and the fact that most exhaust's have a spark arrestor that is greatly needed when riding in the wood's so you dont set anything on fire.

It wont hurt your valve's at all tho, back pressure has no meaning as far as exhaust goes in a 4 stroke motor. All back pressure in a 4 stroke exhaust system does is quiet down the noise and restrict air flow.

If it were to hurt the valve's, then changing from a stock pipe to a slipon would hurt your valve's almost just as much.

The only reason the dealer or a exhaust company would tell you different is because they want your money and they cant have you out there making your own stuff instead of buying their's.

[Drifterboy3]

I don't deny I can get one cheap but having just bought tires and being out of a job I'm short on cash at all. And you will all be happy to know its back on