Should I rejet?

mjgnslngr said:
i feel for ya man, im suffering threw the same JETTING NIGHTMARE!!! 120 main jet in a keihin 28mm and its SOAKING the plug. i ordered a new size needle in hopes that it cures this crap. i should see it tomorrow or wed with any luck. did you ever change your needle size at all?
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No, haven't changed the needle size. I know it is a 1.5, not sure what is stock or should be in it. That gives me an idea though, maybe I should've dropped the clip all the way to the bottom setting, or all the way to the top setting, instead of one clip in each direction from middle. Flooding though, we want less fuel and more air right? Hmmm.

A little background on this, when it actually ran good, :eek: actually it ran fast, on the carb the oil port wasn't plugged off and there was another port :-/ that wasn't plugged (I think the pic is in the first page or two of this thread), it had a #50 pilot (holy-sh*tsky) and a 150 main (uh, say whut?). The air filter looked like it was dunked in an old grease can and sprinkled with rat skat and the silencer had no packing or anything in the can. So, starting with those numbers, and a black spark plug, I've plugged the carb ports, put a new Turbine Core 2 silencer on, changed to a new plug, dropped my pilot to a 30, my main 250-290 (take your pick), new stock air filter and I'm basically shooting from the hip with the numbers I'm given here and winging it. Now I'm at the complete other end of the spectrum with just checking the plug it seems, and I can't get it running in the 1/2-WOT, before it did...power band damn near shot the bike out from under me...lol...not now! :( :-/
 
The pilot in some way affects all settings above it.

If the pilot is wrong, more than likely it will affect up to 1/2 throttle, maybe more.

The pilot must be correct, and must be idling right before you attempt to get the needle and the main right.

Beg, borrow or steal a 32.5 pilot.

If I was nearer I would pigeon post you one.
 
Blaaster said:
The pilot in some way affects all settings above it.

If the pilot is wrong, more than likely it will affect up to 1/2 throttle, maybe more.

The pilot must be correct, and must be idling right before you attempt to get the needle and the main right.

Beg, borrow or steal a 32.5 pilot.

If I was nearer I would pigeon post you one.
Click to expand...

Not knowing for 100% certainty, because I don't have a perfect idling blaster to compare too, I'm pretty sure I have the idling set with my 30 pilot. Here is a question I have though, no matter the size of the pilot, if the idle screw is backed out so it isn't effecting the slide, should I be able to start the Blaster without touching the throttle? So, that would be, the slide is at 0 throttle, completely bottomed in the Venturi, but it should still start. Reason I ask, is I tried that condition last night, with both my 30 and 35 pilots, and I couldn't get it started for nothing! So, I turned in the idle screw a quarter turn into the slide and then it would start on the first kick. And, I will say this, all passages are clear enough to blow air thru...but I am not sure how clean the choke system is as I haven't tinkered with that yet.
 
yes, youi should be able to start it within a few kicks with no throttle, leave the idle screw on enuf to lift the slide slightly to allow some air in


the position of the airscrew, that makes it idle the highest, determines what pilot it needs
if that airscrew/high idle position is........
under 1/2 turn = smaller pilot
over 2 turns out = larger pilot

adjust the idle screw so it is idleing slighty higher than normal, set the idle screw at 1.5 turns out to start.
allow 20-30 seconds between 1/2 turns of the airscrew for the engine to "catch up", then another 1/2 turn, and so on, until you find the position it idles the highest, then adjust idle back to normal with the idle screw
shut it off, then turn the screw in until lightly bottomed, counting the turns in as you do, refer to above 1/2-2 turns to determine what pilot it needs,
no guessing, this method will tell you sure as shizzle
 
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Well firstly all systems should be free from dirt and varnish, and working correctly.

It is very unlikely the motor will start if the slide is bottomed out.

The slide must be up some, so it can deliver some air and fuel to allow the motor to idle.

The air screw adds air to the fuel from the pilot to fine tune the idle mix.

Idle set up is as follows.

Turn idle screw so that it lifts the slide to allow a fast idle.

Turn the air screw in little increments, either way for the fastest idle.

Only turn about 1/8 of a turn at a time, waiting for about 5 seconds between adjustments for the revs to respond.

Reset idle screw for desired idle.

Gee, I hope I got all that right.
 
Man, I know you guys keep telling me the same stuff over and over, and I apologize for that. I get what you are saying, like they say though, the devil is in the details. I'm going to give it one more shot tomorrow night, no time tonight dammit! I'm gonna start with a good cleaning, and if I can get my hands on a 32.5 pilot I'll start there, middle clip on the needle and a 270 main. As usual, I'll keep ya posted.
 
$3.26 later, I now proudly own a 32.5 pilot. Does anyone happen to know the size of the needle in a 26mm Mikuni on a Blaster? The parts guy tried to look, but he couldn't find it and I couldn't find anything on here....my search is limited, people keep walking by. Anyhow, I know mine might be different seeing how I have a 28mm. I did a little research and saw that my pilot and jetting was set close to what my motorcycle is, which is a Kawasaki KZ550 LTD. I also saw, a couple weeks ago, that my carb was most popular on some Russian made Sportster. Knowing, now, that my carb most likely came off a 4-carb dual banked 4-stroke sportster, I'm thinking my needle is probably way off too.
 
mjgnslngr said:
thats all i come up with for a number.
2XJ-1490J-00-00
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Yeah, that's like a stock ordering number or something. PSEP.biz has things like 4J2E, but doesn't list the sizes. I remember looking there and the P/N on mine wasn't even on PSEP, but it was also stamped 1.5...so I'm guessing 1.5 is the size.
 
Actually, I did just find mine and PSEP actually does have it. Hopefully the local parts guy will. What carb are you running mjslngr? Maybe I can find it for ya.
 
I'm in the process of swapping my stock 26mm for a 28mm Keihin. Just waiting on the needles to come from CPW. Once I get one installed hopefully, I'll have to start jetting it all over again. Yay me!!!! Oh, btw, Mjgnslngr is a pita to type. I'm Mike.
 
Mike, Check this out, this is from PSEP. I selected Yamaha ATV, Keihin Jet Needles...
Keihin Jet Needles

Mike is definitely easier, my arrogant Smart Phone wouldn't let me type mjgnslngr for the life of me...little technological POS thinks it's better than me at spelling...well I'll show it, I'll threaten it with a glass of water! I:I
 
So, I'm ever so much closer to running strong in full throttle. I can get to about 3/4 now after a horde of adjustments last night. It comes down to this, with the 32.5 pilot, I got the high idle at just over 3 turns out, so I swapped it out for my 35. With the 35, I got the high idle at about 2 turns, so that tells me that's where I want to be, right? Next, with my #270 main back, I took it for a spin and at about 1/2 throttle in 4th gear, it was really bogging. So, I pull back in and dropped the clip one spot from middle thinking I was flooding it at 1/2 throttle. I take it back out and now it was bogging at about 1/4 throttle. So this time I moved the clip back to 1 above middle. This time, it was running strong(er), but I'm still having intermittent bogging problems around 3/4 throttle. So, what would be the smarter thing to do here, raise the clip to the top spot, or should I look for the correct needle? I don't know what the correct needle size should be, but mine is currently a 1.5, and everything else that was originally in the carb pretty much seemed to be the wrong size. If I change the needle, will I need to change the needle jet also? And plug chopping still isn't an option, not until I get it running to full throttle, otherwise it will be a waste of time because I won't get a true reading.
 
sounds like your getting closer, good call on the 35 pilot, that 3 turns/2 turns told the story !!!

drop that needle to the top clip and see what it does, all those slots are there for a reason
 
Awk08 said:
sounds like your getting closer, good call on the 35 pilot, that 3 turns/2 turns told the story !!!

drop that needle to the top clip and see what it does, all those slots are there for a reason
Click to expand...

Yeah, thought I was going nuts with the 30 pilot I was trying. I felt like someone who was tone def trying to rewrite Mozart's Surprise Symphony. I couldn't tell if my idle was changing or not, even with the idle screw cranked in. Once I put the 32.5 in, started at 1-1/2 turns, and it wasn't changing I was starting to wonder, but when I got 3 turns out, I was like, WOW, now there's a difference! I:I So I swapped it out again and after 2 turns it didn't change again. So then I backed out my idle screw, and it only took another 1/8" turn on the air screw to get a good idle....or at least what I think is a good idle. Funny thing is, when I break hard and come to a stop, it doesn't stall now, it was doing that before...not that that probably means anything, just a quirky characteristic I guess.

I'll try the next slot tonight and take it to my buddy's for a plug chop if I get to WOT without the bogging. Question about the plug chop though, when ya kill the engine, do ya hold WOT to keep the carb open or let off? I know your coasting at that point, but not sure if the air flow, or lack of, makes a difference on the reading.
 
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