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pilot/air/idle mixture screw

22956 Views 25 Replies 8 Participants Last post by  frog13
I want to try to clarify this. When adjusting the pilot screw, turning it clockwise will lean out the mixture. So turning it counter-clockwise will richen the mixture allowing more fuel to enter the cylinder. So if there is a surge at low speed when opening the throttle quickly it needs to be leaner. Correct?

And is there a sweet spot where it will be easy to start and not surge or is it a trade off?
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following this thread with interest since it describes my symptoms well.

( ie hitting the gas after just letting off the gas gives a "lurch" before power comes on )

just cleaned carb - and its minorly better...

altho my gasket was fubar'd so I'm committed to going back in..

my main is a 132!!!!! altho my exhaust is a low slung supertrapp stubby.. ( the way I say my makes it seem like my bike - its not - its the wife's! )

cant tell what the pilot is?

I'm at sea level and its often 90% humidity here.. ( that affects it right? )
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yes a process I was about to undertake,, but was interrupted,,..

- and as someone with an easy to type name ( no not asdfghjh
) has mentioned

should be doing the main jet - then the needle shim's and lastly the pilot..

I have found a post stating that in the hot hot and at sea level then a 132 main jet IS appropriate.. ( by that guy again!
) ( we are usually over 30 degrees celcious - its certainly sweaty here! )

now it seems to me that the main is correct- high end is excellent -

the idle was ok

the only glitch was if I have the gas on - take it off - then pull the gas on hard I get hesitation!

so why was I interrupted,,,?

well I had one day undisturbed to do this and a bunch of other task.. was planning to take carb down to shop to make sure I bought the right jets,,,

loose exhaust downpipe manifold bracket - so put in a new gasket and replaced the bolts ( no choice! they had jumped ship! )

I adjusted the valve clearances - seems the clearances were in the double range..

clean carb cos it had been hard to start sometimes recently.. ( there was a piece of black crub in the pilot ( gasket?) )

well power was definitely improved! noticeable so!

unfortunately what I hadnt noticed was that the exhaust baffle screw ( spark arrester on the supertrapp??) had come off too..

so I blew the baffle out going down a highway when I was giving her some welly!

of course the car behind ran it over

after that I understand why the supertapp is referred to as a megaphone exhaust!
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well for me - Im WOT - change gear - and WOT again on the roads on the TW.. but I'm real quick doing it...

interesting point about the vacumm

I was wondering if that was it - becos that one of the scenario I suffer it in..

car in front slows to turn - I'm off the gas.. then back on it hard to accelerate.. ( hard = WOT )

exhaust is off - getting baffle welded back.. - but I'm pretty sure if I wound on the the gas more gently.. it didnt do this...

bent needle? or the vacum rubber? or that spring in there?

I took the vacuum cover off but couldnt see anything unusual.

thanks - i may try a 130 as we are riding from ground to say 500 meter ( I actually live on a mountain top - but only 10 mins ride to the beach! )

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thats a +1 from me..

looking at the exploded parts carb diagram.. to the right of the "main jet holder" is a rubber seal... I'm not sure I saw that when I cleaned my carb... is something missing? or did I miss cleaning a part of it?

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palmstate - to clarify.. removing the shims have solved your hesitation?

that plug is present in my carb,..

think my hesitation might be vacuum related - cos it only happend after letting off high ish rev's... then going back on the gas..

so it could be something to do with the needle...

the other issues have been solved by a good thorough carb clean and adjustment of valve clearances..
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