still backfires

[suzukimad]

:dunno: After rejeting the bike still backfires a bit.When i opened her up,
and close off the throttle it happens,and under say 4000 rpm..

I have turned the air/fule mix to, 3 3/4  turns out.

do i need to go up a size on the main jets,?>  here`s where i am at.

125 mains,pilots 40. jet needles on 4rd clip position,from top.

The bikes a uk model.........I have k&n air filter in box ,a/v ingnition,and 15 tooth fornt spocket.............


                      tony

[Anonymous]

And you HAVE checked the valve clearance right?

[The Buddha]

K&N with choker means 125, no choker = 127.5.
However check for hoses cracked or missing ... the one on the bottom of air box and the crank case vent at the top. Then 127.5 ...
Still 4K is rather low for main jet ... Try 127.5, but lower the needle ... from 4th clip from top to 3rd from top, and go to say 3 1/4 on mix screw ... The theory is you may ahve compensated for mains by richening the air screws and needle and this seems to be a weird side effect in the area where neither is in charge ... I know I am being vague ... but Its in my head and cant get it on paper. Try it and see ... Carbs are fluid mechanics ... somehting I instinctively knew when in engineering school despite having no feel for any thing else like concrete structures which all my fellow students understood ... I was just left with a blank look ... Of course studying it was not an option ... so what is a boy to do ...
Cool.
Srinath.

[Gisser]

I assume you mean popping sounds and not actual backfiring.  Looks like you've already done what can be done for the condition; the rest is the price you pay for having a no-backpressure aftermarket pipe.  

[suzukimad]

No not poping,it backfires.I think the choker is off the k&n.It`s that rubber ring that fits over the hole right,is it hard to remove,?.it may have fell off,as i had the filter on the bike for about a year now.before rejetting
Sriath,the 3rd position groove from top on the jet needles,is stock position..is that ok,?>

I check the hoses first.have never check the valve clearance done 22,000
And had the bike at 18,000..maybe it`s time..is this a hard job to do.


                          Tony

[The Buddha]

Ok my bad... thought #2 from top was stock ... OK you leave it on #4 and try 127.5's ... no choker is 127.5 ... Just swap that in and check it ...
Cool.
Srinath.

[suzukimad]

Cool,will do.Take it the chocker is that rubber that fit`s around the top hole of the filter :dunno: .

if so how hard is it to take off,because i did try geeting it off,when i did the rejetting.

                              Tony