I doubt that you need to change cables or mill anything to get a stock cable setup to open/close a slightly (1.5mm) overbored 38 mm carb set.

I suspect you've installed the cables incorrectly into the slides. This reduces the amount of free cable length.

 

what could be the could be the problem with the installation? im very sure that the high idle is due to the slide sitting to high off the idle postion but al of them were the same height. unless i installed all 3 of them wrong somehow?

 

There is a cutout in the slide for the idle screw to go against. if the slides are in backwards the idle screw cant do its job. Take an other look.

Dieter

 

Unhook the cable and adjust with the idle screws.Leave the springs and caps in place. Are the bores off center to one side or the other?

 

just got my sled running and i beleive there is a problem with the carbs, possibly stretched cables. even though the idle screws are completely out on all 3 carbs, when the sled starts it shoot up to about 6000 or 7000 rpm. when i synced the carbs i made it so that at full throttle the slides completely cleared the carb. but at the same time the slides seemed to sit a bit high at idle. i thought i would be able to adjust this with the idle screws but apparently not. another thing i noticed also is that when the slides completely clear the bore and the throttle is wide open, the throttle iteslf doesnt touch the bar anymore. apparently the cables could be stretched or the slides arnt supposed tom completely clear the bore? the cabrs have been bored to 39.5mm and the slides were cut accordingly.

Cut? Why? Where?

 

On bored ROUND slide carbs you have to remove some material from the TOP of the slide so it can open all the way without hitting to bottom of the mixing chamber cap, I do those all the time on my lathe after boring the carbs for others.

 

The other problem could be that the cables are not seated inside the slide corectly. They are in too deep. Check that as well. Been there done that. On wrong and the whole engine runs wrong

 

ill pull the carbs today and see whats up. ill post pics later on. i know the slides are in the correct way i remeber making sure of that if they are in the wrong way the slide doesnt go all the way down in the carb and i dont think the cap can even be screwed on properly.

 

That's what fooled me on the dirt bike,,thought the cover wouldn't go on but it did,,I figured all Mic's would be the same,,now I'm going out to try My 340 since the engine is on the bench.. need to know,, R2R

 

alright so i just pulled one carb and went over everything again. looks like i didt everything right the only thing that i did notice is that when the throttle cable slips into the topof the slide, theres 2 notches on the cable that can go into the slide. one is at the end of the line and the other is a little ball just above the one at the end of the line. i had it so that the little ball and the end part of the line were in the slide. so i tried it without the little ball part in the slide and it dropped the slide alot. but now i cant even get the slide to clear the carb at WOT with the cable this way. It clears the intake side but not the motor side.

 

alright so i just pulled one carb and went over everything again. looks like i didt everything right the only thing that i did notice is that when the throttle cable slips into the topof the slide, theres 2 notches on the cable that can go into the slide. one is at the end of the line and the other is a little ball just above the one at the end of the line. i had it so that the little ball and the end part of the line were in the slide. so i tried it without the little ball part in the slide and it dropped the slide alot. but now i cant even get the slide to clear the carb at WOT with the cable this way. It clears the intake side but not the motor side.

You screwed up by placing the cable too deeply into the slides as was suggested at least twice. Apparently you now have it correct. If you've used up all of the adjustment in the cable adjustments, you could install a 1/16" washer under each cap.

 

Well.. I went and pulled my carb apart on my 340.. it slide in but about a 1/4 was still sticking out,,cover almost screwed on,, not sure where the carbs were cut but if it's around the top i can see these being put in backwards ,, anyhow,,that's all the guess I can do..good luck.. courious to know what you find out.... R2R

 

the slide can only go in one way, if not the notch for that little pin in the cab will hit the slide on the way down and about 1/2" of the slide will be sticking out of the top of the carb. The only thing i could think of would be if the slides were htting the top of the cap because they were cut enough. ill get some pictures uploadidn in a couple minutes of how it looks now.

 

when I tried it the whole slide will almost go in and you can pretty near screw the cover on..where are they cut at?? ok,,looks like your getting it streightened out,

 

Alright so this is how it looks not with the cable in the right part of the slide. this is the most i can get out of the cable with only a few threads screwed into the top of the cap.

at WOT:

 

well it turns out that the cable position in the slide was wrong. after i did all 3 carbs correctley, now i can clear on the intake and exhaust side while the idle height is nice and low. thanks for the help guys i appreciate it.

 

just finished getting the carbs back on and its still doing the same thing for some reason. it revs up to about 4500 now and i backed out the idle screws alot on all 3 carbs. I guess i could drop the slides a bit more on all of them but then they wont clear the carb at WOT. Not really sure what to do at this point.

 

are these the old original carbs, or new ones for the machine. I used to set the idle on these with a 1/8 drill bit on the motor side/ Adjust cables and screw so there is only enough room to slide it i. Then open the throttle and make sure all three crack open at the same time. Make sure as you open the trottle more they all act the same. How far do they go up after this

 

They are the original roundslides, I just had them bored. I'll try the drillbit trick later tonight when i get home from work. I was pretty surprised when the idle was still really high because the slides were siting pretty low but I'll try the drillbit trick like you mentioned and I'll see what happens

 

alright i used the drill bit trick and it worked!!! the sled idles a bit high but not too bad. the slides didnt completely clear the carb bore but there was only a little bit of the slide in the bore at WOT. thanks mike

 

Bored carbs can be a MOFO. You may need to adjust the airscrews a tad for the idle. At 39.2 you can get up to 5% more flow so you will have some tuning.

 

yea im pretty much out of adjustment almost for the idle screws, might be able to get another half turn out of each before it doesnt make a difference.