300ex problems

[brettg]

i ahve a 2000 300ex with a wb e-series and had a K&N filter on it. I changed the stock jetting to a 118 main n put the e-clip 4 nothces down as my dealer told me to. When i started the bike it still backfired so i adjsuted the fuel screw and still it didnt help. i checked the plug n it looked a little lean. I decided to take off 2 discs from the exhaust hoping to richen it up.When i did it began to backfire louder wiht more of a pop to it. Instead of ripping apart the carb again.


I WANT TO KNOW IF I SWITCH BACK TO TO THE STOK FILTER, WILL I RUN RICHER, AND DECREASE THE AMOUNTOF BAKFIRING....AND ID REATTHER RUN A LIL RICH THAN LEAN

ANY HELP WILL WORK

[bwamos]

The dealers reccomended jetting sounds off.

Is your airbox lid on. Or is it off or vented?

Lid on. id start at.

122k-125k Main.
Needle clip 4th slot from top.
2-3/4 turns out.

If getting backfire.. may possible need a 40 pilot.

Airbox lid off or vented you may need up to a 130k main.

[honda300EXtreme]

yea, i would start at a 125 keihin and then fine tune the carb from there

[brettg]

well i ride at real low elevation, and i forgot to say i have the dynojet kit, and witht he lid on with a aftermarket pipe, 118 main n 4th clip down is waht i need..


i jsut need to know if switching back to the stock filter will richen the mixture and decrease the backfiring:confused:

[300exOH]

Originally posted by brettg
well i ride at real low elevation, and i forgot to say i have the dynojet kit, and witht he lid on with a aftermarket pipe, 118 main n 4th clip down is waht i need..


i jsut need to know if switching back to the stock filter will richen the mixture and decrease the backfiring:confused:

If it is backfiring on decel then you need to adjust your pilot circuit. Try adjusting the pilot screw(air fuel screw) first and if that doesn't fix you you'll need a larger pilot (40-42 keihen) Switching to the stock filter may help but you will lose a little power which would defeat the purpose of bolting on an aftermarket pipe IMO.

[brettg]

alright ill try adjusting the mixture screw n see how that does.....i also ahve a slight crack in my headpipe so i tinhk that also could be affecting the backfiring....thanks

[brettg]

alright ill try adjusting the mixture screw n see how that does.....i also ahve a slight crack in my headpipe so i tinhk that also could be affecting the backfiring....thanks

[bwamos]

Originally posted by brettg
well i ride at real low elevation, and i forgot to say i have the dynojet kit, and witht he lid on with a aftermarket pipe, 118 main n 4th clip down is waht i need..


I just need to know if switching back to the stock filter will richen the mixture and decrease the backfiring:confused:

The stock filter will allow less oxygen. It wont richen it perse'. But it will make it less lean (less oxygen).

If you're running the Dynojet Kit, I'd put in the 120 DJ (it's easy). Since you get more flow at the top end with an aftermarket filter & pipe, than you do with a stock filter & pipe.

Easy way to test it it to remove the airbox lid. If it gets worse.. you are lean with it on. If it gets better you are rich with it on.

[bwamos]

Originally posted by brettg
alright ill try adjusting the mixture screw n see how that does.....i also ahve a slight crack in my headpipe so i tinhk that also could be affecting the backfiring....thanks

Yes, that is definatly causing an issue if it is within 4-6" of the head to pipe connection. If it is take it to a local welder and get it welded up for $10. The added oxygen into the system can also burn your valves/seats.