38mm PJ On an 85 T3

[85Tecate]

Ok, for the sake of god. If someone is running a 38mm PJ Flatslide on their 85 tecate, can you please give me your jetting specs if your stock or near stock. I've been chasing this down for months now with no success at all. It's starting to cost alot of money :D.. I'm on a fresh top end btw.

Current im running a 230 main (which is too small i think. When i crack the throttle from about 2nd gear in low rpm it will bog) I've got a 45 pilot (which is too big i think because it still _almost_ wants to load up at idle, and i dont have to use the choke to start it cold. If i do use choke it will flood out.) and my clip is 2nd grove from the top.

These are near stock settings for the stock carb on the T3. But since this is a 38mm carb the jetting is way different. My main problem is if i BARELY crack the throttle, just enough for about 2000-2500rpm, and i hold it there i will foul a plug within a matter of 5 seconds. Any other throttle position is fine other than WOT because of the main i believe. I go through about 3 plugs every day i ride. All of them are wet fouled and black with little buildup.

[Jason Hall]

I would start with a 170 main (Keihin jet, not Mikuni), 45 pilot, needle on the second groove from the top. Keihin jets don't run the same numbers as a Mikuni, If you put a mikuni number size jet In a Keihin carb you will drown the engine bigtime.

[Jason Hall]

John, I think what he has going on Is he looked at the stock main jet In his Mikuni carb. He then bought a 230 main jet for a Keihin carb, and that Is a HUGE jet for a keihin carb. Mikuni jets size numbers are way different. I would guess a 200 main In a Mikuni would be close to a 150 In a keihin. A PJ carb Is a keihin oval slide carb.

[85Tecate]

I would start with a 170 main (Keihin jet, not Mikuni), 45 pilot, needle on the second groove from the top. Keihin jets don't run the same numbers as a Mikuni, If you put a mikuni number size jet In a Keihin carb you will drown the engine bigtime.

Youre still recommending a 45 pilot even though the mikuni's pilot is a 45? Im running a 45 now and it seems too rich to me, maybe ill throw a 170 main in it and see if it helps any. That seems like a huge difference from the 230 in it now. I will try it though. Anything is worth a shot at this point.
I appreciate the response. I'll let you know what happens tomomrow.

Edit* This thing started out with a 252 main in it when i bought it. With just a DG pipe and silencer.

[nd4speed]

My 86 KX250 has either a Keihin 38mm PJ or PWK and the mains I use are 160 and 165.

[85Tecate]

Ok so i put in a 170 main and a 40 pilot. I ran it at idle and tried to foul the plug like i did before, but it wouldnt foul. I gave it a few good revs, but cant take it for a spin till i fix my shifter. My plug looks weird. Its white still, but on one side its blackish/dark brwn the rest of the insulator is white still lol.

My air screw is only about 1/4 turn out, but almost seems to run better with it all the way closed. I think i might have went a size or two too small on the pilot. I may try a 42. I have another plug so ill do a plug chop (wide open) to check the plug then, but right now i get a quick throttle response when i snap it open and a nice high rpm. She sounds good. I may be a little lean though.

BTW those damn jets are expensive. I paid 9$ for the main and 6$ for the pilot :(

If i turn my air screw out any further it will bog when i snap the throttle wide open. What causes this?

Keep in mind i ran a 45 pilot before this and my air screw made no difference where i set it, it still reved fine, but smoked alot and fouled plugs just off idle. Im thinking a 42 pilot is about what i need. Think so?

[85Tecate]

Update. I upped the pilot to a 42 and it seems to be alot better. No more delay when i crack the throttle from a stand still. Ive got a very light tan on my plug which is good so far. I havent taken it for a ride because my shifter is fcked. I have to get a new one.

[85Tecate]

Update 2. Figured id mess around a bit with it tonight and i rode it around the yard for about 15 minutes cracking the throttle every now and then. Mostly putted around. Pulled my plug and found it to be a flat black color, not wet, with a few very dark brown spots on it and a film of oil around the flat ring on the plug. I dunno wtf im doing wrong. My air screw is screwy as well. If i turn it in, the RPM raises and smooths out at about 1/4 turn, but if i open it up it seems to run like trailprotrailprotrailprotrailpro. Where do i go from here? Smaller main? Surely not a smaller pilot....My needle is 2nd groove from top

[Jason Hall]

Are you sure the carb Is a PJ??? Do you adjust your Idle speed with the choke knob?

[85Tecate]

Yes, im 100% positive it's a PJ. And yes my choke knob is also my idle adjustment. It's alot closer than it was before i can say that much. The plugs before were wet and black. Now its a dry black look with a few very dark brown spots in it also. I'd say i probably need to just drop the main down a couple sizes and maybe drop the needle one more.

[Jason Hall]

I would start playing with the choke/Idle adjuster and the air screw. Turn the air screw 1-1/2 turns out, then see If you can make It Idle better by turning the choke/Idle adjuster down. If you can, then fine tune with the air screw until It Idle's best. The main jet control's wide open throttle. The other thing to be SURE of Is that you have the throttle cutout facing toward's the rear of the carb. The cutout Is the rounded part that Is on the bottom of the slide. I bet thats your entire problem now that I think of It. It will pull fuel straight from the main jet as soon as the throttle starts to open. Check that first.

[85Tecate]

I would start playing with the choke/Idle adjuster and the air screw. Turn the air screw 1-1/2 turns out, then see If you can make It Idle better by turning the choke/Idle adjuster down. If you can, then fine tune with the air screw until It Idle's best. The main jet control's wide open throttle. The other thing to be SURE of Is that you have the throttle cutout facing toward's the rear of the carb. The cutout Is the rounded part that Is on the bottom of the slide. I bet thats your entire problem now that I think of It. It will pull fuel straight from the main jet as soon as the throttle starts to open. Check that first.

Hmmm, You're a genius! I will be sure to check that tommorow, all along i figured it only can go in one way like the old round slides do. Ive just been putting it in any ol way and it always drops right in...I will definatley check that though, thanks alot. I'll update this tomorow

BTW, if i turn my air screw 1.5 turns out, the engine will idle way down and start running rough and also ill get a bad hesitation when i crack the throttle from idle to WOT. Thats why i kept it at 1/4 turn where it runs its best at (fastest idle and no hesitation when i snap the throttle). If i close it now, with the 42 pilot, it will eventually die after about 10 seconds or so. Im guessing its flooding when its closed.

My plug after a 170 main, 42 pilot and 25 minutes of slow (1st gear riding in circles with a few blips of the throttle to slide the rear a bit)

http://i1017.photobucket.com/albums/af297/bspoores/DSCI0127.jpg

[Jason Hall]

Check the slide, as that will make Everything change. The air screw will act totally different once the slide Is flipped.

Looking at that plug like you are really Isn't telling you anything at all. You need to look at the smoke ring WAY down Inside the threaded part of the plug. You need to figure out what the engine Is telling you by what It sounds like, and how It feels. Your learning the HARD way LOL, which Is the best way!!! As you tune and figure out that certain thing's don't work you learn from that. Before you know It, you have that thing screamin, and you'll know what you did to make It happen :beer

[85Tecate]

Check the slide, as that will make Everything change. The air screw will act totally different once the slide Is flipped.

Looking at that plug like you are really Isn't telling you anything at all. You need to look at the smoke ring WAY down Inside the threaded part of the plug. You need to figure out what the engine Is telling you by what It sounds like, and how It feels. Your learning the HARD way LOL, which Is the best way!!! As you tune and figure out that certain thing's don't work you learn from that. Before you know It, you have that thing screamin, and you'll know what you did to make It happen :beer

You know, my father always told me i learn the hard way...But i always manage to get er' done! Thanks for the input, i will tinker with it some more tonight.

[85Tecate]

Hello, just an update on my plug pics. This is after a "plug chop" 5th gear wide open. I did this 2x with the same plug, because i forgot to take a new plug with me. It turned out GREAT but in my opinion, just a HAIR too lean. I may bump the main to a 172 and leave it to be safe. The plug picture thats posted in my previous posts is with this same jetting, but riding very slow and lots of idling. I will lean those out next until im satisfied. Here is 2 plug chop tests and remember, this is the SAME plug thats posted in my previous post which was black from slow riding, idling. Im going to say my main is almost spot on. Big thanks to Jason for all the help. ive been fighting this for some time now.

http://i1017.photobucket.com/albums/af297/bspoores/DSCI0133.jpg

http://i1017.photobucket.com/albums/af297/bspoores/DSCI0134.jpg

Just wanted to inform you that im running #50 slide and a 1370 needle. Do these sound correct?

[Jason Hall]

Been away a couple days, glad you got It figured out. Not sure on the slide or needle number's that you listed.

I like to make my 250r's surge, or stumble at Wide Open Throttle, them back them down til they pull clean. That way you know for sure you have It right. You should know what rich feels like by now :lol: :beer so I would try a 180-185 If you have one, and If that makes It stumble at WOT, then back er down to a 175, or 172.

[85Tecate]

Sounds great. I havent messed with it since the last pics so ill do that when i get the extra time. Probably this weekend. Thanks jason. I still think im way rich on the low side so thats next :)

[Jeepermc]

So...Rather than start a new thread....I've got a question about carbs too... My stock carb is kinda messed up...Fixable but it needs a rebuild and I haven't found a kit for it...

I picked up two carbs yesterday. A 35mm PWK and a 39mm PWK to try out...Actually the 35 is for a single conversion on the banshee... is a 39 waaaaaay outta line for a tecate? A friend of mine ran this carb on his 250 quadracer for a little while and didn't like it... what say you guys?

[MagicJames]

Don't be afraid to start a new thread, Everyone's questions are a little different, and this board has members that have no problem stepping in and helping.

No 39 isn't too out of line.
If you're running stock porting and stock pipe, i would probably lean towards the 35 as it will probably be a better match for a stock motor. But the 39 would work just as well, just get more fuel into the motor.

[85Tecate]

Mine seems to run great with a stock motor and 38mm keihin. I still havent got the jetting right, but its closer. I did foul a new plug last time doing half throttle donuts in the mud. So i know my problem is in the needle and still some in the pilot. If you jet it right you should be just fine.

[Jeepermc]

Thanks guys.. I'll give it a shot and report back next week...Heading for the dunes again for thanksgiving.

John- I was hoping you'd chime in with your thoughts on the boot!...Thanks again.

BTW- What is the stock size carb? and does anyone know where I can find a rebuild kit? I fired it up the other night and it idled up real high...Killed it and went to adjust the idle screw...and it was gone!:lol: Must have vibrated out....

[Jeepermc]

Good point..... Dang rattle trap!....lol I discovered a pretty bent and worn needle while tinkering with it too...

[85Tecate]

That might be some of the high rev problem right there, sucking air in the hole where the idle adjustment screw fits in.

john

I dont understand? Explain please?'

Edit* Sorry noticed you replied to him.

[Jeepermc]

I managed to get the swap done on friday on a wing and a prayer...She runs real good and I actually got a whole ride out of it without worrying if I was gonna make it back to camp... Still need to do some tinkering with the thumb throttle swap as it's not "right" but it works and is not unsafe...

I saw all 3 of the big 2 strokes this year at Coos Bay, OR. My Tecate, bunch of 250R's and a tri-Z....Lots of 200X's and even a few 350X's running around... Big trike presence this year...

[Jeepermc]

I'll put my jetting here for reference too- I'm on a 172 main and a 52 pilot. Sea level 50-60 degrees outside.

[ATCLUVR]

So, was the carb slide in "the wrong way" like jason said or was that not the issue?

[TheFamer]

Hey quick question i wanted to run by you guys. you are talking about a keihin 38mm flat slide carb right? well i just got a 36mm PJ round slide i believe out of a trade. do you guys know anything about that size/kind? i have heard its for any 250cc 2 stroke bike. but what about trikes? any input would be great

Thanks guys. hope you figure this carb tuning out. i am having trouble myself with a 34mm flatslide mikuni for my XR280L.. i need to buy jets and needles first. Good Luck!

[85Tecate]

Hey quick question i wanted to run by you guys. you are talking about a keihin 38mm flat slide carb right? well i just got a 36mm PJ round slide i believe out of a trade. do you guys know anything about that size/kind? i have heard its for any 250cc 2 stroke bike. but what about trikes? any input would be great

Thanks guys. hope you figure this carb tuning out. i am having trouble myself with a 34mm flatslide mikuni for my XR280L.. i need to buy jets and needles first. Good Luck!

Mine is a 38mm keihin PJ oval slide. You sure yours is round not oval? It works on trikes too, yes but needs to be jetted for each application.