19mm phbg help, clarification

e50, 65 metra kit, matched and lightly ported, proma circuit. hi-comp head, plug chop looks good, carb completely cleaned out and gas running clean from tank.

19 phbg, with polini hi flow filter.

i've read the phbg wiki stuff...but need a little help making sense of this all...

currently jetted at: main jet 90, idle jet 45 (common size on spreedsheet) choke is 60?

bike starts without using the choke, will only run if idle screw is all the way in(turned clockwise) needle clip at highest setting(lean if i'm reading the wiki correctly) and fuel mix all the way in as well. flush with the cab body.

idles so low that the back wheel doesn't spin unless throttled and once it warms up and i've ridden around a few minutes i've got to throttle it a little bit to keep it running.

if i back out the fuel mix, or idle screw the bike dies.

bike has good acceleration and doesn't lag when throttled...1/3 to wot is great, no problems. just idles really low.

any help would be great, i'm sure i'm just not understanding something simple. do i up or down jet from this point to get the carb idling enough to be able to use the fuel and idle mix screws full range of adjustment.


Re: 19mm phbg help, clarification

You haven't mentioned what characteristic of performance that you would like to improve.

Re: 19mm phbg help, clarification

yeah, i'd like it to not idle so low, but i'm maxed out all the way in on the idle screw and cable adjuster is all the way out as well...

Re: 19mm phbg help, clarification

If it won't run with the slide almost bottomed out you have an idle mixture problem. You can't adjust the idle mixture properly with the slide up much at all

Re: 19mm phbg help, clarification

so back off on the slide, fire it up and play with the fuel mix screw?

Re: 19mm phbg help, clarification

Yep. Once you have it running reasonably rev it up and close the throttle to let it idle. Then if after the rpm settles down the idle wants to increase you are too lean. If it lowers you are rich but you want to be a little rich so when you close the throttle at speed you still get plenty of fuel and oil. When coming off a hot high rpm run or going down a long hill always pump the throttle to ensure you have enough lubrication entering the engine

Re: 19mm phbg help, clarification

sounds like i'm too rich, should i downjet the idle jet or the main jet?

i've never messed with an idle jet on a carb before...only had a bing and a mikuni that both were set up pretty good when i got em.

Re: 19mm phbg help, clarification

No. Mess with the mixture screw. That should give you enough adjustment to bring the slide down with the idle adjuster screw.

Re: 19mm phbg help, clarification

Yea screw it in for lean and out for rich forget about the main jet and needle for now

Re: 19mm phbg help, clarification

Probably Fred /

#40 idle and smaller main jet

Re: 19mm phbg help, clarification

- Summerai - Corey Livieri /

Go Ken's route. I've tuned a couple of 19's and that's what I've had to do.

Re: 19mm phbg help, clarification

Thanks dudes!

Re: 19mm phbg help, clarification

if you are having to screw the mix screw all the way in, you are too rich on idle jet. mix screw should tune in at 1/2 to 2 turns open. tune the first 1/4 throttle first with idle jet and mix screw.

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