34 mm PJ baseline jetting

[musselman]

Hey guys I'm just setting up my 34 mm PJ carb and i'm wondering what jetting specs will get me close. I did some searching for jetting specs on here but I didn't find anything specific to the PJ. I just don't want to buy a whole bunch of jets trying to figure out where to start. My mods are a vito's 240 kit, airbox lid removed, fmf fatty/pc2, and v-force reeds. Just the main, pilot and needle/clip position would be great, thanks

 

[djack12]

I would say start with the clip in the middlem As far as buying a bunch of jets, that is the only way you can really do it.

 

[blasterfreek30]

prolly somewhere between a 145 and 155 main, shoud be right

 

[musselman]

Ok thanks, my smallest main right now is 160 so i will need to get some smaller ones. Any recommendations for the pilot size? Right now i'm not sure if it's lean or rich on idle but I don't think it's even close.

 

[blasterfreek30]

pilot jet should be somewhere around a 40 or 45

 

[blastapole]

yeah mines a 142 on a stock bore with porting so a 145-155 is gonna be your bet.

 

[musselman]

Thanks, I appreciate the help

 

[musselman]

So I finally got around to getting my jets. It has been running pretty good with a 155 main, however I have yet to figure out the pilot. I got sizes ranging from 38 to 48 then I have a 55 and 58. The sizes in the 40's sound to lean, like it is running out of gas, but the idle doesn't hang it just dies. Also there is no throttle response off idle.
I have a vid of it running with the 55 pilot, it has a huge bog off low rpm. Once it gets going it's ok. Also it will idle for about 30 sec with the 58 pilot, maybe 5 with the 55 in the vid and not at all with one in the 40's. Does that mean I need to go bigger? Also the idle/choke knob is adjusted all the way out for max idle

 

[B_Rad_NC]

Not sure about yours but with my 35 i tried running some of the reccomended jetting on here and mine was running lean as hell. Its about cherry with the needle in the 3rd clip and a 170 main. I tried a 165 main and the plug was bone white after riding for a while, raised the needle and put the 170 in and it looks good. My pilot is too big and its a 48, i will probably drop to a 45 and see how it does then. I have a pretty decent bog in the low end.


Best thing to do is check the spark plug.

Also set your pilot screw on 1.5-2 turns out while checking the pilot jet.

 

[musselman]

well it run's ok other than the idle. Right now I'm not sure if I need to go leaner on the pilot or richer. Would the needle setting or main jet have an impact on the idle? Maybe thats my issue.

 

[Luni]

You need to get it to the point where it will idle with the idle screw 1.5-2 turns out.

Keihin carbs all have a slide stopper screw you might just need to adjust that by screwing it in farther, which would make the slide sit higher, and allowing more airflow at idle.

Also, your needle clip is responsible for the instant off throttle response, so you could have your main and pilot on and needle wrong and it would still bog or not run right off idle into throttle.

But ideally, you know youre in the realm of the correct pilot when your idle screw is 1.5-2 turns out, and your bike will just idle nicely.

Generally, you can tell if your pilot is too lean because your idle will be HIGH. I just put a different carb on mine and its pilot is too lean. I had to turn the idle screw all the way IN to get it to idle right, otherwise its idle was HIGH. Thats too lean. Too rich is if you have to turn the screw all the way OUT or you can even remove it and it still isnt right.

To be honest, yours sounds too rich

 

[musselman]

Thanks for the info. I didn't know there was a slide stopper screw, that could very well be my problem maybe. Do you mean on the top of the carb on the cable?
However when I do adjust the air-screw it doesn't change anything so that's why I'm lost. I think it sounds rich as well but if I go leaner the idle is much worse.

 

[Awk08]

mine is just tits with a 45 pilot, it'll start only with the choke pulled when cold and 1 kick every time after warmed up, and turn that choke back down the whole way and adjust your idle with the cable at the throttle, that choke/idle thingy sucks balls, only use it to add a little fuel for fine tuning, how can just adding fuel increase the idle without adding air too????
i'm also on middle clip and a 155 main, anything richer and it runs like sh*t, but i do have a slight bog at 1/4 throttle when the needle kicks in and i dont even wanna try the second slot down, gonna try a different taper needle soon

 

[Luni]

Thanks for the info. I didn't know there was a slide stopper screw, that could very well be my problem maybe. Do you mean on the top of the carb on the cable?
However when I do adjust the air-screw it doesn't change anything so that's why I'm lost. I think it sounds rich as well but if I go leaner the idle is much worse.

I had the same issue, about the idle screw not changing anything, I was able to adjust the slide screw to get it to stay.

However, ive been looking at yours, I dont see a slide stop screw on yours. Heres a pic of my PWK36mm

Notice the screw that appears to be above the fuel line port? Thats a slide adjustment screw. I dont think yours has that. Yours supposedly works off vacuum and adjusts automatically? I dont know. Its just what I was reading about PJs.

 

[Awk08]

no the pj's do not have a slide adjustment screw, or a place to put one, i looked very good, they work off the choke circut, by adding fuel, or should i have said "try to work"
i thought i was doing sumthin wrong using the cable to adjust the idle, then one of our well respected bro's said last week thats the way to go

 

[musselman]

I have heard so many different things I don't know what to believe. Some say choke knob is good some don't. I know mine idles great with the cable tight but will that increase the chance of a sticky throttle?

 

[Awk08]

no your cable will be just fine, unless its worn or frayed < the most common problem with sticky throttles

 

[musselman]

Well I'm still a bit lost with my pilot jet. I have a vid of it running with the 58 pilot with the cable tight to raise the idle. In the vid it idles high but if I leave it for about 20 sec it will come down. That to me means that I'm still lean.

 

[super noober]

^^^^ that dosent sound bad to me... i think its idleing a otuch high because of your tight cable. IMO if you cant get teh machine to idle just using the carb then something is dirty or just plain not working right.. with my 34mm pj my idle is perfect starts first kick no choke and it will respond to turning the choke knob. with my mods im running a 162 main and 55 pilot. good luck man

 

[yb200]

pilot runs the idle .