Another Carb Question?

[rjf2369]

I have a 79F with kerker 4-1, Individual air pods, and dyna coils. I'm having a problem with my Idle, without the gas tank on I've been running the engine(with a fan on) It seems to be running way too rich (Black smoke). I have my floats set at 26mm, stock jets (for now), metering rod set 1 notch down I've set the mixture screws at 1 and 1/2 turns and had them all the way down to 1/8 . I just went through these carbs very thouroughly with K&L kits and installed VX920 viton needle and seats the carbs are not leaking fuel. Also when remove the gas can and let it run out of gas the idle picks up and the engine picks up smoothes out and the black smoke is gone. Wheere is the fuel coming from should I lower my floats. I have a lot of money invested in this bike but with all the headaches this bike has given me lately I thought about just fixing it with a match!

[DGXSER]

Well, assuming you have the 79 version of the carbs, the stock float setting was 25.7 with the gasket off from the gasket surface. If it runs better when it starts running out of fuel, I would definitely try raising the floats (lowering the fuel level).

Have you confirmed what year the carbs are? Do they have the plug over the pilot jet opening? Could also be the newer carbs that you overjetted the mains thinking they were the older ones. But then, the newer carbs had a lower float level (meaning a higher fuel level in the bowl). So you should be starvign them with that float level.

Guess I confused myself more than cleared up your problem.

[dbeardslee]

What's your jetting? The '79 carbs have a range of adjustment from 24.5mm to 26.5mm on the float height, so at 26 you'd be slightly towards the lean side. K&L kits are a new one on me. Using other than Mikuni jets can cause unpredictable results. A mikuni #147.5 isn't necessarily the same as another manufacturer's 147.5.

[rjf2369]

I just went out and checked the old jets the former owner had 180's in the mains? Could there be a reason for this big bore kit or something? I noticed when I adjusted the valves that It had a new cam chain in it so I figure it had some work done to it at some point. I also cheked the valve lift on the cams and they are stock lift. I've went through carbs on other bikes many times but this one has me confused. I checked the carbs too and from what I know about them they are correct for the bike, It has adjustable Idle scews not the recessed and the pilot jets are covered with screws I didn't see any passageways when I had them apart. It seems like It's drawing fuel from somewere other than the pilot system.

[red bandit]

Did you take the emulsion tubes out and clean them? Did you clean the air jets to them also? What are the #'s on the pilots and mains of the K&L's.

[tarzan]

Your mains should be 137.5's.Maybe a little bigger for your configuration.
Some times the kits come with the wrong size jets.You have to check each one before installing.
The last kit I ordered,I think they were K&L brand,I got 130 mains.I had the right jets already in the carbs,so I just didnt use the K&L ones.

[TopCatGr58]

Hey RJF,

As has been mentioned, sometimes places will sell you the wrong kit or K&L will have the wrong type pilot jets in the kits(see MikesXS.net for pictures showing difference of VM vs.BS pilot jets)...this has been known to happen MANY times with MANY previous members. IF you have the OEM pilot jets, and they are not damaged, CLEAN them well, ensure that the small side ports are clear, and put them back in the carbs.

Other things to check, that you have the fuel lines connected to the LOWER T fittings only, the upper ones are bowl vents. The upper ones NEED to be properly vented....not capped off.

Next, what brand/style of Indy pod filters? The Emgo brands have a prominent lip on the inside mounting edge that can block the air flow thru the ports in the inlet bell, and again cause overly rich running. A search for Indy Pod filters, along with a look in the tech tips for velocity stacks mods and such.
T.C.

[dbeardslee]

Your mains should be 137.5's.

That's the stock jetting on '79 carbs. With his mods (4/1 and pods) he should be 4 jet sizes bigger on the mains, and 1 size bigger on the pilots according to the jetting recommendations. He's got basically the same setup I do, and I'm running 147.5's mains and 45 pilots and it's on the money - confirmed by colortune and my right wrist .