Popping On Deceleration

[Newrider08]

Hey guys, I have a question for you,

I notice when riding down hills in first or second gear without giving it any gas im getting some popping from the exhaust, I checked where the pipes bolt to the head and all is good there. I found a loose rivet on my White brothers e-series on the bottom that has been leaking but I dont think that would cause it?

I have a white brothers e-series that has been welded onto the pipe, im not sure if its the stock pipe but im pretty sure it is. I dont know what the carb is jetted at as I just recently bought the quad. I put a new plug in it to read the plug and after about 20 minutes of riding on a new plug it was cardboard brown but did have some carbon on it. I thought it may be running rich then so I pulled off my airbox lid and it ran like crap.

what are a couple things I could look into now?

[Homerx]

Originally posted by Newrider08
Hey guys, I have a question for you,

I notice when riding down hills in first or second gear without giving it any gas im getting some popping from the exhaust, I checked where the pipes bolt to the head and all is good there. I found a loose rivet on my White brothers e-series on the bottom that has been leaking but I dont think that would cause it?

I have a white brothers e-series that has been welded onto the pipe, im not sure if its the stock pipe but im pretty sure it is. I dont know what the carb is jetted at as I just recently bought the quad. I put a new plug in it to read the plug and after about 20 minutes of riding on a new plug it was cardboard brown but did have some carbon on it. I thought it may be running rich then so I pulled off my airbox lid and it ran like crap.

what are a couple things I could look into now?

Idle to 1/4 throttle circuit is lean, up the pilot jet or open fuel screw.. GL

[honda400ex2003]

go out a quarter turn at a time on the f/a screw and see where it gets you. if you are more than 3.5 get a bigger pilot and start over from about 2 turns. I am assuming you are at a 38 now and a good place to start with the f/a is about 2.5 or 3 and go out from there. Otherwise you may have an exhaust leak at the head or somewhere else. a little bit is normal. if it does it when you on flat and let off the gas richen it up otherwise it could be the slopes not letting enough fuel in the carb momentarily. good luck, steve

[n811]

But some is normal. Its from the engine breaking. The extra drag from deceleration will use the engine to slow down and change the firing a bit. You should not have a loud BAM, ever. Thats from being real lean and the fuel fumes back up when the rpm's cut down quickly and the fumes fire up much more easily. Test this by reving in neutral(warm engine of course) and let off, if no "popping" You are probably not too lean. its always safer to run a bit rich though. Unless your a racer and tear down your top end a lot.

[Newrider08]

The weird thing is I didnt notice it popping on decel until after I adjusted my valves back to spec, they were not way out of spec but there was some slop there

after the adjustment is when I started noticing it

[honda400ex2003]

it may have leaned it out being that it is not letting quite as much in and out since they are closed longer now than before. I am not sure by any means, just an idea, anyone think that sounds ok? steve