Hitchcocks Forum

just cleaned out the carb on my 350 bullet and found the pilot jet was blocked every thing else looked fine . only now once it starts it runs on tickover for 10 mins then stops , on checking the plug it was black and sooty , new plug and lots of kicking the same thing , Any one got some advise. Thanks.

Is this a Mikarb? You didn't lose the washer under the main jet? Is the choke on? (plunger down is choke off on the 350)

It's a MIkArb Washer is ok. , the choke Off , plunger down for off ? Well it's back to the garage to regroup and check
Will report back
Mick

Why are you letting the motor idle for 10 minutes?




Pilot air screw may be set too rich (turned in too far) ? 1.5 - 2 turns out is normal...


Plug may be too cold? Gap too large?

PeterF, what is the significance of a washer under the main jet?
Just checked the parts list & a washer is listed, but to the best of my knowledge the Micarb on our Bullet has never had a such a washer.

Yes it is; every carb has the washer. The Jet abuts up against it to pull down and secure the needle jet.


With out the washer, the 'float level' relative to the main jet is changed by nearly 1mm and has a direct bearing on the effect on venturi depression.

All i know is, I once missed out the washer and got symptoms like this.

Plug sooty /after/ tinkering with the fuel means idle is too rich. Yes swap to a clean plug with correct gap then do what Tim NZ said about the idle. The number of turns on the bypass is the starting point not the end point



At 10 minutes warm up my bike starts running hot, they're air-cooled so they don't like sitting stationary too long. The electronic wizardry (AT-200) on my C5 lets me see the air-fuel ratio, after several minutes at idle and the motor overheating, the AFR goes completely to pot, so when tinkering with the idle I have to stop and let it cool.



I set a carb idle 'by ear', it's richer than the main jet but it's only like that with the slide down and the needle closing the jet; and so it is with injector too, idle is supposed to be a little rich but not sooty. If idle is also drawing significant fuel from the main jet (missing washer?) then it will run too rich; the needle and slide must be down against the stop and the cable have some slack. Set the stop to give the correct (a drill bit) air-slide gap.

Thanks Peter & Tim
I do not normally feck around with things that are performing reasonably well but here may be an exception to my rule.
I will look at both the Micarb on t' Bullet & the monobloc on the Flash & a Box. I am sure neither have any washer which I assume to be a fibre item, if I'm right then I will fit one & see what happens. If the bikes run like a bag of shyte it will be easy to go back to as is now.

Bryan, on the Mikarb it's a brass washer - almost a spacer if I recall.