jetting help 28mm pwk...

[mjgnslngr]

ok, put the 28mm pwk on, started with a 160main, 50 pilot. way too rich. started my way down and got to a 130 main, 45 pilot. Needle still in the middle. And its still rich. now to me, that doesnt sound right. i have no a/box lid, fmf fatty exhaust and its still stumbling in the high end, only at wot. As i jetted down from 160 it got better each size down. At 130, its almost gone but its still there ive read other post with guys running the same carb and basically the same set up but theyre jetted somewhere around 150,what am i missing??? The blaster idles good, about 2 turns out. Midrange is powerful. But as soon as it gets to wot, it stumbles. The plug is alittle wet also. The float height is set to spec. So what could it be? Do i need to keep jetting down? any help would be appreciated!!!

 

[mjgnslngr]

so, i guess there no one owns a keihin carb or had ANY issues jetting?

 

[mjgnslngr]

anybody?????????????

 

[mmajay]

I dont think i would try and lean out any more. You should be around 150 main. Something is not right here.

 

[mjgnslngr]

I dont think i would try and lean out any more. You should be around 150 main. Something is not right here.

Thank you! thats what im thinking too!!! i read something about the needle??? maybe the taper sizing making it too rich for the main??? again, thanks for the help!

 

[mmajay]

Thank you! thats what im thinking too!!! i read something about the needle??? maybe the taper sizing making it too rich for the main??? again, thanks for the help!

It could very well be the needle. What your describing sounds like its getting to much fuel at WOT but a 130 is crazy low for a main.

 

[mjgnslngr]

i stopped going down on size at 140 cause thats as small as i had, then i found a 130 and tried it for the hell of it and the wot bog got a little better still. i pulled the carb and im getting the needle out today to see what kinda numbers its got on it.

 

[mjgnslngr]

the needle #s, N5HG ???? the only thing i found with those numbers was this;
http://www.ktmshop.se/documents/9661_Teknisk_Data_Motor.pdf
everything says this needle is off a 2010 ktm 85sx

 

[Triple_B]

I don't know if this helps at all, but I'm running a Keihin PWK28 on my setup.

I've got Aggressive Trail Porting (Triples and Boyeses), Ken O'Connor Rechambered Head, Boyesen Pro Series Reeds, Toomey B1, and no airbox lid.

With this setup, a 155 main and 50 pilot is giving me the best results so far. I haven't done plug chops yet, for one - its not even ride able yet, two - I have NO WHERE to get this thing in 6th WOT.

 

[98blaster+4]

keep going up and see if it gets better. you should be around a 150-160 main

 

[slickerthanyou]

the needle #s, N5HG ???? the only thing i found with those numbers was this;
http://www.ktmshop.se/documents/9661_Teknisk_Data_Motor.pdf
everything says this needle is off a 2010 ktm 85sx

The stock needle in an OKO30 is N80F, I believe I ended up with a (leaner JJH needle and fourth position) And it was happy.

Here is a link for needles- JETS R US KEIHIN NEEDLE N427-46

Leak test it first, if air tight, Then jet seeing as you already did the float!

I agree you should be in the 150-160 range on the main

 

[mjgnslngr]

The stock needle in an OKO30 is N80F, I believe I ended up with a (leaner JJH needle and fourth position) And it was happy.


Here is a link for needles- JETS R US KEIHIN NEEDLE N427-46

Leak test it first, if air tight, Then jet seeing as you already did the float!

I agree you should be in the 150-160 range on the main

thanks slicker, thats what i needed to know! the needle thats in it is a ktm 85 number. when you say fourth position, you mean one Up or one Down for the clip? and wasn't there another needle the dgl or something they had rich problems with?

 

[slickerthanyou]

thanks slicker, thats what i needed to know! the needle thats in it is a ktm 85 number. when you say fourth position, you mean one Up or one Down for the clip? and wasn't there another needle the dgl or something they had rich problems with?

Yes there was I can't remember what the letters were but there was another..

Fourth clip position from the top!

 

[mjgnslngr]

Yes there was I can't remember what the letters were but there was another..

Fourth clip position from the top!

DGH, i found a post by awk that said something about he had issues with it and someone else. mines N5HG which is an oem number for a ktm 85 sx. i didnt figure that be too rich for the blaster right?

 

[mjgnslngr]

i did a wot test today. so, heres the plug with a 120 main, 145 pilot and needle in the middle. no need to cut it, its BLACK. wtf? why is this thing running sooo rich? it idles good, fairly snappy but Still bogs slightly at 3/4 to full throttle. i dont dare go any smaller a jet. any help?????:-/

 

[Blaaster]

Silly question I know, but is that a B8ES plug??

 

[mjgnslngr]

Silly question I know, but is that a B8ES plug??

no question is silly! i need all the help i can get, yes, it is a b8es.

 

[Blaaster]

Could the flywheel have slipped into retard, I know I am clutching at straws.

 

[mjgnslngr]

Could the flywheel have slipped into retard, I know I am clutching at straws.

thats not clutching at straws, thats checking variables! no, i actaully changed my flywheel last week. it runs good with the stock carb but, when i put this one on it runs STRONG! just cant get the jetting to match. why would it be running this rich with a 120 main? could the needle size do this???

 

[Blaaster]

Try a chop at 3/4 throttle thats where the main takes over from.