Engine trouble still

[laganm21]

Ok two weeks ago i have to replace the crank case bearing and seals because it would suck in air at idle a rev up, but now after the fix its doing the opposite, now what its doing its perfect at first it fires right up and idles great, then i drive it around for a min or two come back and it wont idle any more it wants to die, so i turn ths idle screw in and it idles fine again take it back out around the yard and come back and still don't want to idle , its funny because before i replaced the bearing and seals it idled to high now after the fix it wont idle

 

[laganm21]

Also i have replaced the whole carb and gaskets, new head gasket and all the carb setting are at factory specs, this is ready getting frustrating because it seems like something so small that I'm over looking

 

[laganm21]

yes i used a old intro pipe nipple and drilled it into the top of the cap and took out all the inside stuff except for the big rubber half ball and ran a fuel tube to the top of the roll cage with a filter, i do have a small exhaust leak but its on the baja SS pipe where the to half's join together with a clamp it not bad , tonight just to see if that was the problem i put my old exhaust can back on and still the same issue

 

[DemonRC]

What's ur needle settings at?

 

[laganm21]

There at factory specs 1 1/4 L 1 1/2 H

 

[kryptonite]

leg. if your at factory settings and its idling too low that meens its too rich on the low side. so if you lean out the low side needle a hair(clockwise) the idle will go up. it just takes a 1/16 of a turn. you might have to adjust the idle screw close to were it was prevously. i never to hardly ever use my idle screw to adjust the idle. if its idle is high or low its for a reason. maybe too lean or rich. the idle screw will give you a sense that its running right whaen its not. good luck homey

 

[laganm21]

I seen what your saying But when i adjust it to run and idle after its warmed up than when i put it up for the night it try to fire it back up the next day when it cold it revs so high at first till it warms back up again, is that normal ive never seen one do that before

 

[laganm21]

Thanks moo i have not even touched the H needle yet, Ive just messed with the low and the idle screw, i try what you sayed when i get home and give you an update i hope this works im sick of it not running right lol

 

[kryptonite]

no, your right. it should be consistant time and time again. it doesn't really sound like an air leak, but


-double check the carb and manifold seal. (im sure you probly all ready did)


-make sure the fuel line is going to the right place


-check the pulse port on the manifold. it may get covered by the gasket(will couse some sort of flooding


-presure in the fuel tank. that will couse what sounds like a bad tune. clean out the cap and open the wholes. might even take the nipple out for the test run.


-check your fuel. did you just brew a new batch? if the fuel is too rich it will mess up the tune as it gets hotter.


if you checked all those things and your still stumped, i would look into compression. how is the cylender/piston. did you see any scratching on it? maybe time for a new ring? if its "ring time" then as it get warm it will lose compression cousing a low idle. leaning it out will soon couse it to heat soak and idle too high.


while doing these road tests get it so you can pull the plug right away. the color of the plug will give a good idea of whats happening.

 

[laganm21]

Hey kryp when i pulled the motor apart it pistion look good it had some little marks on the pistion sides right above the the hole where the conection rod mounts but noting bad at all, it look really good inside there, i have made sure the pulse port is not coverd by the gasket, and just checking the fuel line that has the filter it the tank gose to the bottom of the carb, I am running the same gas i have allways ran not a new batch, what MOO sayed sounds good it makes since if the high neddle is rich because when i do a high speed run i stop right after that, thats when it starts to idle bad and want to die would the exhauset leak cause any of these problems.

 

[kryptonite]

ya. i would lean out the high side anyway for peak rpm. my carbs don't run well at stock setting once the motor is broke in. i doubt you have ring problems unless your have alot of gallons on it and the scuffing on the piston sounds minamal. the high side needle doesn't play a part untill about 1/4 throttle, but as moo said it could very well load up the carb and have some sort of effect on the idle. try to do some adjustments on a stand to get the carb away from the stock settings. becouse you have changed so many things on the motor(i.e. pipe,carb seals) your going to have to find the "sweet spot" for the needles. to get max rpms(and close to the right high settings) rev the motor while leaning out the high side(clockwise). once it hits peak rpm back it down an 1/8 of a turn so its not too lean. back out the idle screw so its not touching anything and do some quick start and stops till it go's smooth. first on a stand, then on the ground. it will most likly idle low and you'll have to keep it going or adjust the idle as you go. it sounds like just getting the tune will put you back to normal again. the leaking exhoust mani will have some sort of efect on the tune, but not major. you should just tighten it up anyways. just take your time and if all else fails go back to the stock settings and start over. you'll always want to lean it out from the stock settings as they are as rich as you can go. if you happen to get it warm and consitant with a decant idle, your going to want to run it for a bit and do some high speed runs to check the plug color. keep us posted on what you do and what seems to work.

 

[laganm21]

Engine update well this weekend i took my truck out and try and try and try to get this thing to run right, it will just not hold a tune, ill get the low end to work but the high wont and vice versa, so pretty much the awesome weekend was a wast it was 78 and sunny, This weekend my Friend (K20_ 94dc) traded a Hpi baja SS for a TT that has a 28.5 head kit so the guy gave him the stock 23cc head never used so I'm going to install it today just to seen if this solves my problems don't think it will but all i can do it try