yet another jetting question

[sbjones73]

ok guys and gals. i know, another jetting question. here goes.

i have an 84 250r bored to 71.50 and i have a pj34 carb. i am currently running a 48 pilot jet and a 165 main (i now main will to big but i wanted to go rich from the start)
i am starting to dial in my idle to start things off. i am following the duncan racing's jetting information. i have the trike idling pretty darn good,my air screw is out like 1 1/8th turns . but here is my problem. when i blib the throttle, the rpm's hang up there for a bit, like 10-15 seconds or longer if i hold the throttle open more.
i have pressure tested my engine several times. and there is no leaks. could my main be causing this problem, or my needle height ?

thanks, and any information would be great,

[sbjones73]

ok a little more information. i am running 92 octane gas with a mixture of 32:1 with belray oil.

the engine is smoking pretty bad compared to other 2 strokes i have had, doing a compression test i have 175 after 10 kicks. it has only been ran 3 times for about 5 minutes a piece, tring to brea it in the rings a bit before any load on it.

is my pilot setting still to lean? i tried a 52 pilot and the air screw was out like 3 1/2 turns to get any idle fluctuation. with the 48 it is out 1 1/8 turns like stated above. i do have a 50, i might try that, but wanted to see what you all thought first,
again , thanks

[oscarmayer]

the problem is your too rich. it's dumping so much fuel the engine has to catch up. you need to run a smaller main. running rich does NOT mean your safe nor does it mean your running correctly. If your not certian how to tune it, then take it to someone who can and buy several correct sized jets.

you probebly don't want to go more than 3-5 sizees bigger than stock toi start with. Stock i think was what? 140 or 145? so try a 150-153 jet.

set the needle on the top notch as well.

[Jason Hall]

I will suggest you turn the air screw In a slight bit at a time. Don't mess with anything else. Leave the choke knob/Idle adjuster alone In the beginning, and just play with the air screw. The problem your experiancing Is you are just a BIT lean on the Idle circuit. This can usually be tuned out by finding the correct balance between the choke/Idle adjuster and your air screw. The more you close the air screw, the less the Idle should hang, but It might drag the Idle down, and cause It to load up. Next spin the choke/Idle adjuster to raise the Idle slightly. Then go back to the air screw. Let us know how you make out.

[sbjones73]

hey jason, thanks for the reply first of all.
you suggest that i am lean on the idle circuit. should i then install a 50 pilot instead of the 48 and see how that goes? or just try and balance this out?

which would be safer or better for the engine? i have to say that when i had the 52 in there the rpms did not hang up at all, but the air screw was out a ways.
let me know which way you think, pilot or screw adjustment.

thanks

[Dirtcrasher]

I'd follow exactly as he suggested before changing the pilot.

If you end up changing some jets, just make sure to change one at a time.

Changing mains and moving needles in one shot doesn't help you, it doesn't tell you where the issue was affected be it good or bad. It normally gets people completely lost.

[Jason Hall]

Yes, what DC said, one thing at a time and you will learn from It. I would try to tune It out with the air screw, and Idle adjuster. Your In the neighborhood with the 48 pilot, so I think I would stick with that.

[sbjones73]

ok thanks. i will let yo all know, i have it at work and am going to work on it later tonight.

[sbjones73]

ok guys a little update here.
jason that worked like a top, thank you very much. i was pulling my hair ouot (i am bald, so really no hair to pull out) but it idles like a champ!!!

got my new needle in also, my old one was bent. power is very good through the mid range. started doing plug chops, i will have to post some pics of y plug. i know that it is a little on the rich side,but my engine has locked up 2 times on me. so i was planning on being rich. i think now is just messing with my needle height, let me know whaat yo all think after i post some pics ( problably in a day or 2 for pics) i will try and get a vid of it running on here also.

again thanks, that is why these types of forums are great. info, info and more great info!!!!!!!!!!!

[sbjones73]

ok i did some riding today, matter of fact a bit right in my yars. here is the plug after some light to moderate riding. doing a plug chop the plug is still black, but not this black. . i8 have a 48 pilot and a 150 main right now. needle on the 3rd clip.
i also have included a pic of my trike, just to let you all know what i have been working so hard at.

[Dirtcrasher]

Nice trike

Yes, that looks rich but I hear ya on the past lock ups. Was the carb too lean in the past or is there another issue causing the seizures??

I wouldn't be afraid to drop the main one size and or lower the needle, but like I said before make sure to do only one at a time, test test test!!

[sbjones73]

thanks dirtcrachser. well in the past i am sure i had some air leaks. this time i pressure tested and everything. so for sure no air leaks this time.

i took it out to a local track today, seemed to run pretty strong. but kind of lazy. i think i will lower the needle one clip and see what happens. still kind of wiery about really hitting it hard, but i has to come some time. i am going to take my time

thanks. i am trying to figure out how to post some pics, but i am like an idiot when it comes to this dang thing.

again thanks

[sbjones73]

i meant posting some video's with sound.