Jetting Problems?

[XxMeltIcexX]

Well, I just rebuilt my engine... Heres whats going on:

34 mm PJ's

BEFORE: CEG needles middle clip, 60 pilots, 162 mains

NOW: CEL Needles middle clip, 55 pilots, 162 mains

 

It wouldnt idle before, now its idling - still needs a bit of tune up, it bogs down low when WOT from idle but picks up, i tried 57 pilots, made it worse, keep screwin with needles and middle clip is best. My local shop even says they hate them, we worked on it for 6 hours! Still cant get it tuned, they are telling me to try a timing plate (To help the bog). Well after a longer ride yesterday, it ran great for about a mile, then on the way back up it just starting cracking up on top (loss of power also), cylinders were hot to the touch (kept finger on for 3 seconds, no longer or i'd burn myself) - lesson learned my exhaust pipe fried my hand after i was startled by the heat of the cylinder lmao... Seems to me that the coolant is flowing fine (and the hose isnt boiling - as its not super pressurized..) Also, these were RNBRADs' cylinders before, said it likes 55 pilots and 160 mains, but it boggles me that before i changed pilots and needle the top end was running awesome, those should not affect the main jet whatsoever right??? I'm very frustrated with the way its running, anyone have any ideas, anyone know how to tune these PJ's??? Oh, and anyone have 160 mains?? Also, i just changed plugs, my BEFORE setup fouled them up..

 

Thanks,

Eric

[XxMeltIcexX]

Going for a ride right now, to try each throttle position see if i can get more info to put in here...

[XxMeltIcexX]

Pulling Plugs:

Keep in mind i'm using a castor oil..

 

1/4 throttle:

Left side is chocolate milk.. mm not to dark either...

Right side is the same...

WOT:

Left side is chocolate milk (same as above)

Right side is Milky - too lean i can tell..

 

Whats with this?? How do i fix it? I'm confused .. i dont wanna use two diff mains in each carb...

I was WOT in 4th - pulled in clutch - turned off...

[dajogejr]

wesw has a lot of experience tuning the 34PJs..

Also...did you leak test the motor, compression test and measure the squish, as well??

 

Milky?? Is it possible you're leaking coolant into the cylinder?

It should be black/brown/tan/white....NOT milky.

You're either leaking coolant into the cylinder, or you're trying to burn gear oil via a bad crank seal....

 

Post up pics of the plugs...please.

[XxMeltIcexX]

milky as in a very white brown --- if i was burning coolant or gear oil wouldnt i be seeing a shitload of smoke??? I hate hearing that, i dont wanna tear that shiznit down again... lol... the seals are brand new also... havn't done a pressure test, being the ignorant person i am i thought i did it right.. always costs me it seems the bike ran great on my little ride.... just that plug didnt seem brown enough..

EDIT: i did a comp test, only 120 psi in both cylinders.... I thought i'd have alot more - maybe cause of my port job?? i know its more than that when the engines running for sure...

 

Eric

[dajogejr]

milky as in a very white brown --- if i was burning coolant or gear oil wouldnt i be seeing a shitload of smoke??? I hate hearing that, i dont wanna tear that shiznit down again... lol... the seals are brand new also... havn't done a pressure test, being the ignorant person i am i thought i did it right.. always costs me it seems the bike ran great on my little ride.... just that plug didnt seem brown enough..

EDIT: i did a comp test, only 120 psi in both cylinders.... I thought i'd have alot more - maybe cause of my port job?? i know its more than that when the engines running for sure...

 

Eric

 

120PSI with 18cc domes (the ones in your sig???)

That's not right, here's what could be causing it.

 

Bad/cheap gauge

You're higher than 3000 or 4000 foot elevation

You didn't kick it long enough or enough times

You've got a bad seal somewhere.

 

Trust me...leak down test the motor.

My 4 mil cub had all new everything, still had a massive air leak at the base gasket....no mater how careful you put a motor together, shit still happens.

 

You may or may not see smoke from burning coolant or gear oil....depending on how much is burning..

Do you have a pic of the plugs??

[XxMeltIcexX]

Bad/cheap gauge

You're higher than 3000 or 4000 foot elevation

You didn't kick it long enough or enough times

You've got a bad seal somewhere.

 

3500 ft elevation... kicked it so many times, wouldnt go past 120, gauge could be bad?? was friends gauge... what size are the threads for spark plug? i'm going to go get one myself, and i guess i'm going to go to ace and get some supplies for the leakdown, what do you use for your pump? and i dont have a pic of the plugs, didnt have a camera while doing it, and by the sounds of it i dont wanna ride it til i pressure test my crankcase....

[dajogejr]

You hold the throttle wide open as you were kicking it?

According to Dave Noss's site, your compression should be between 165 and 170 PSI with 18cc domes at 3500 ft.

Now...that's a fresh engine, stock bore, stock stroke. Now...keep in mind, porting will lower your cranking compression a little....but I can't see it lowering it that much.

 

I'd try a new, quality compression gauge first...Craftsman, Snap On, etc. not an auto parts store cheapy...

 

You can make your own leak down test kit for checking seals, etc., or...you can buy one already made.

PM Machwon on here, he's R&B Racing out of Michigan...and he sells a nice kit.

[wesw]

first off wasnt brad motor a 4mm not sure might be why you have such shitty compression.

 

 

you need to figure that out first.

 

 

 

brad is at a 1000 ft if that, your at b.f.e 3500 ft. so you cant run the same jetting as him you will be beyond rich.

 

i would put a 50 pilot in, get it to idle. and see where the air screws are at. if more than 2 turns out to get it to idle smooth and not at a fast idle go lower.

 

 

you will need a carb sync tool to really help you along. jeff sells a good one. get with him.

 

after you get the bike to idle and the air screws like 1.5 turns give or take a bit. take it out and ride it, get it warmed up. then slowing open the throttle up to about 5/8 throttle. it should be a smooth transition into the pipe. if it is smooth or decent try the 4th clip, if it bogs or acts up go back to the 3rd clip.

 

 

then after you fell it is smooth, start doing the mains 155 would be a good spot to start. 5th gear wot, 4 sec then kill it, pull clutch and stop as fast as possible, then pull plugs

 

try to get them carbboard color.

 

your going to have to get your compression figured out, it wont run the best till you get some more psi. at least 160 psi my guess.

 

 

let me know if you need anymore help or are confused as fuck now. lol

 

they are easy carbs once you play with them,

 

 

 

wes

[XxMeltIcexX]

wes, thanks for info, these are brads stock cylinder trinity ported... It idles great, this is the closest i'm gotten it, i tried a 50, was a no go, believe me its as close as its going to get with the pilot and needle... i'm really thinking i might have some problems with a leak somewhere... cause i knew 120psi wasn;t sounding right.. like i said i'm going to pull em off and do a crankcase pressure test.. and i'm going to go get a new compression gauge ... i'll keep you updated, thanks for all the help guys..

 

Eric

[bigboybanshee]

On tuning the carbs, I was told that the idle adjustment is in the choke knob. You screw/unscrew that to adjust how it idles, and if you unscrew them too far they will have an effect on the overall performance of the carb. Just an idea, but check to make sure both of the choke knobs are adjusted the same. :thumbsup:

[Bansh-eman]

thats right bigboy... the idle is the chokes... when i had my PJ's i ran 55 pilots and 155-158 mains... and im at sea level.. the nobs where turned way out to get it to hold idle...

 

did you sync your carbs?

[XxMeltIcexX]

idle is great... only 3 turnes out for idle ..and 3/4 on air screw ... i didnt sync them no.. havn't gotten that far yet, hopin i dont have a leak first .. prayin that is! :ermm:

[RNBRAD]

Yea I don't know anyting about the PJ's since I've never used them. That motor with 18cc domes should be well up around 170 to 180. You have a problem somewhere with that low of compression, assuming your tester is accurate. You should also be running 110 race gas. Do a leak down test just to cover that area. Even as meticulous as I was with my cub build I had a pretty large leak around my base gasket at the front of the motor. Yea I ran 160 mains and 55 pilots CEL's mid clip in 35mm pwk's and is was perfect at around a 1000ft.

[wesw]

idle is great... only 3 turnes out for idle ..and 3/4 on air screw ... i didnt sync them no.. havn't gotten that far yet, hopin i dont have a leak first .. prayin that is! :ermm:

 

 

something is goofy cause every pj i played with it took at least 8-9 full turns out to get it to idle.