I'm probably going to be upgrading my stock muffler and air filter soon. As far as the exhaust goes, it'll just be a modified slip-on muffler with the stock size exhaust pipe since they don't make a complete system with piping for my Linhai Wrangler 260cc. With just doing a muffler and air filter, would I have to do any carb jetting??

 

Check out the scooter websites as this engine originally (built by Yamaha) was designed for. Then quad manufactures in China copied the engine and stuck it in quads/scooters. They may have kits and tips to get more out of it.

But in general I don't think you'll find alot of aftermarket stuff for it to bolt on. Anthing is possible however just depends on how hand you are with wrench and welding.

 

Dude I think you need to find your oil filter first (kidding!!). I'd see how it runs after the exhaust mod, then gauge it there if you want to mess with the carb.

Joel

 

Any muffler and or filter change will lean out a already lean engine...bigger jets will be needed.

 

So would simple mods like that just require a mian jet change? My atv has a #128 main jet so the online manual claims.

 

I'm assuming it would be best to error on the rich side, so starting with something like a #140 main jet after the air filter/exhaust upgrade would be alright?

 

Another question based on my own ignorance. I'm new to ATVs (well.. I've been out of if for 25yrs). If you modded your air filter and exhaust, how will you know your fuel trim is leaned out too much? Will it run like poop? Start running hot and turn to molten metal madness?

Joel

 

140 sounds like a good start Blubyustang88. I would try a larger pilot jet...really helps with warm up and low speed throttle response...

PoManzATV, Any time you modify either the intake (fliter) or exhaust system. Assuming your going to a less restrictive filter and exhaust. You are now letting more air in, but no more fuel..Larger jets do that... All of these Chinese ATV's come jetted lean from the factory to pass CARB and or EPA tests. Most do better with larger jets any way. Open up the intake and or exhaust and its a necessity.

A lean engine will sort of starve for fuel. Sort of like its running out of power...

Rich will blubber and sputter while not making power.

 

The other thing to mention here is a leaner fuel mix burns hotter. If it's too lean you burn up pistons and valves so pay close attention to how your engine's running.

 

Right, that's what I was getting at. Will these engines act like they're running lean after you mess with the air filter and exhaust or will you not know until it's too late?

Joel