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Discussion Starter · #1 ·
got a 93 indy 440, trail ported, .080 over weisco pistons and 34mm mikuni round slides. trying to fine tune the carbs, put new br9es plugs in it and new fuel filter, new plug wires, cdi is good.

when i hit the throttle it hangs at 2200-2500 for about 4 seconds, ive got the idle set low at 1600. it does this regaurdless if i just feather the throttle or if i rev it enough to engauge the clutch. im wondering if its running lean and should i adjust the clip on the needle or adjust the idle air mixture?

it comes down from 6000 just fine but when it gets to 2200-2500 it just hangs there for about 4 seconds. it didnt do this untill i changed the fuel filter.

oh it has stock exhaust too :)
 

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Discussion Starter · #2 ·
anyone? we'r suppose to get 5-8" of snow tomarrow and i reallly don't want to burn down my engine on the first ride of the season. i ask because in my mind, if you take out a 17 y/o fuel filter and give it a brand new one you would think it would give it more fuel, but it hangs at 2200 like its acting lean, and it didn't do that before the new filter. normally i would just figure its lean on the low end and adjust the air fuel mixture screw, but this ones confusing me.
 

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The carbs might be out of sync. I know our old xlt would act goofy like that when they were out of sync.
 

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Discussion Starter · #4 ·
the only thing with that is i just spent all day cleaning them and syncing them, the last time i synced them myself i brought it to a respected shop and had him clutch it, even though i already synced them i had him do it just to double check my work and he didn't have to touch them. i synced them the exact same way as i do every year
 

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Have you checked to see if there are any cracks in the carb boots? Spray some starting fluid on them and see if it revs up. That will cause it to run lean like that.
 

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Discussion Starter · #6 ·
yep, carb boots and the base gasket are fine. I called around to some shops and they said there might still be an air bubble in the new fuel filter?
 

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That could be possible. I haven't really heard of that happening though.... I'm not sure of what else it could be?? Maybe try some new fuel. Sometimes new gas from the pump can be bad.
 

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Did you check all of your fuel lines and vent lines?
Or make sure that it isn't your throttle cable getting hung up on maybe one carb, maybe the cable is getting pinched or something?
And as far as I know you are supposed to burp those new filters.
 

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Pilot jets are 35's stock which are lean but with new top end may be lots too lean, could try 40's. Make sure throttle cables are not tight.
 

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Discussion Starter · #10 ·
Thinksno said:
Pilot jets are 35's stock which are lean but with new top end may be lots too lean, could try 40's. Make sure throttle cables are not tight.
could be that, all the fuel lines are still good, no leaks anywhere in the system, it does have stock pilot jets though. And the slides arent sticking the cable seems to be in good order, im just confused as to why it would suddenly start doing that after the new filter. Because you would think that it would be leaner with the old clogged filter and the new filter should allow more fuel flow.
 

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I think one or both of your pilot jets is plugged. Remember, the pilot jet affects low RPM, the needle - mid-range, and you're on the main jet only at 3/4 to wide open throttle. A lot of people seem to overlook cleaning these jets. It happened to me all the time on my '96 XCR440. You can spend a lot of time chasing other possibilities, or take ten minutes to do this free, simple procedure. It makes sense to do this every year anyway.
 

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Agreed. It only takes about 20 minutes to take the carbs off and clean the pilots. Get a wire and run it through the small holes, then blow air thru.
 

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Discussion Starter · #14 ·
amsoil intercepter, and the carbs have been cleaned as they are every year, every jet, ever nook and cranny of that sled gets gone through every season. Took it out today and it stopped doing it, and hasn't done it all day.
 

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Clean your pilot jets.
 

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Discussion Starter · #16 ·
shortstop20 said:
Clean your pilot jets.
I know, thats what everyone else said, but as i said 3 times already. They've been cleaned, everything got cleaned, they've been cleaned twice in the past 3 weeks only because I got bored, they were cleaned again last night because of the idling issue. And they were still just as clean as the last time I cleaned them, took the pilot jet and main jet out, can see through the hole clear as day. No obstructions
 

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What about the holes on the sides of the pilot jets? They can plug very easily, they're only the size of a pin hole.
 

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Discussion Starter · #18 ·
Those are also clean. Both carbs were completely gone through last night. Maybe something just got lodged in there from when I changed the fuel filter and somehow managed to knock itself loose while i was taking the carbs off? lol I dont know, all I know is they're spotless.
 

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Sounds like you know how to clean pilot jets. In case you don't, there are TEN holes. Eight on the sides, and two on the top and bottom. Sorry if I'm telling you something you know.

DO NOT mess with the needle setting. That's the quickest way to burn down your sled. LEAVE IT STOCK. Remember, LOW RPM = Pilot jet, MID RPM = Needle, HIGH RPM = Main Jet.
 

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Discussion Starter · #20 ·
LOL ok I'm sorry but this is starting to get frustrating, ITS NOT the jets, that sled gets gone through thoroly (exucse the spelling) every season. I know about the holes on the sides too, it's actually pretty hard to miss them when you look at the pilots. I may not be the best speller but I do have quite a bit of common sense, if it was as simple as the pilot jet being plugged I wouldn't have even posted on here, but they weren't plugged.

It ran fine BEFORE I changed the fuel filter.

Here is a list of what I have done to diagnose:
- checked all fuel lines for leaks
- checked fuel pump and pulse line
- ensured the new filter is facing the right direction
- sprayed carb cleaner around the boots and base gasket to look for leaks
- cleaned carbs, this included pilot jets, main jets, choke, it wasn't just a "pull the bowls off, quick spray, done" it was a thorough cleaning.
- checked the plugs to see if it was too lean
- plugs didn't look too scary so took it for a spin and for some reason it stopped hanging at 2200, it idled right down, will have to see what it does tomarrow.
- and yes the engine was warm when it first started having the problem, I never even think about hitting the throttle while its cold.

and thanks for all your suggestions and input :) still appreciated it
 
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