BST36SS carb expert needed.

[yoshisakan]

Now cylinder 1 won't fire and cylinder 4 works fine. I wonder if there's a problem with this dyna 2000 Or the coil

[Carter Turk]

Do you have a tee downstream of the petcock? What float height you running?

[yoshisakan]

Carter - There was a tee and I figured out that each bank of carbs were steaing fuel from each other. Now i'm temporarily running a direct fuel hose to each from a 2 valve pingel. Float height is about 17mm. I increased it from 14.6, there was no discernible difference at either setting. I think I need to get a set of 40 pilot jets.

I just don't understand why it's not firing on all cylinders, when I first started it after taking the carbs apart this last time, it fired on all 4 for like 3 or 4 seconds, then cylinder 1 cut out. This is with the choke on and I know the choke circuit is working properly. I pulled the wire from cylinder 1 while it was running last and it was sparking.

[Carter Turk]

I wonder what would happen w/o the plugs on the pilot jets. My 1990 36mm bst don't have caps on the pilots, but they're off an 1100. Maybe the 750 pilot jet plugs aren't compatible with the Bandit 12 engine, and the displacement is demanding more air/fuel than a 750 Katana would. Is it too cost prohibitive to just get needles that are designed for the 750 emulsion tubes, instead of mixing parts?

Doesn't look like the 97-2000 Bandit carbs have plugs either. Maybe the pilots are starving for fuel after initial startup
and can't replenish quick enough, that might be why it stalls after few seconds.

[yoshisakan]

Carter - In theory that sounds like it makes sense. I started the bike with and without the plugs and there wasn't much of a difference, but I've made so many changes that I'm not sure if I fixed something else. I do know that since I drilled out the air jets to 1.5 that i'm going to need to increase the pilot jets. I'll probably try 42.5s.

Also I bought bandit emulsion tubes, so my needles/tubes match @ 2.5mm. Katanas are 3.0mm. This further complicates the tune in my mind because with the pilot jets plugged the pilot circuit gets the fuel mix from the needle jet.

I really should have got rs36's or bandit carbs, but everything I read said that bst36ss were pretty much the same across the board. I've found enough minute differences to cause a few weekends of headache and a few hundred dollars worth of parts.

[yoshisakan]

Turns out my pilot circuit was way lean, I installed some 40s and got it to idle, although it was still lean, so I have 45s on the way. Cylinder 4 still won't heat up like the others. It's cool to touch while the others are burning hot. It's not the coils, wire or spark plug. You'd think that would leave fuel, but the choke circuit is working. I'll look at the carbs again while installing the 45s to try and figure it out.

[JTGS850GL]

The choke is fed through a very small brass tube that goes into a well in the float bowl. If you remove the enrichment plunger on the carb body and shoot some carb cleaner through the hole at the end using the thin straw on the carb cleaner spray bottle you should see a solid stream of cleaner coming out through that brass tube. If not then the enrichment circuit is plugged. You should also be able to spray down into that well in the float bowl and see a stream of cleaner coming out the hole at the bottom. You will need to pull the carbs to do this.

[yoshisakan]

I boiled these carb bodies and went through 2 cans of carb cleaner, id be very surprised if that brass tube was clogged, but i will give this a shot when I replace the pilots.

[JTGS850GL]

If you didn't dip them then the boiling alone would not have done it. You also need to probe the bottom of the float bowl well and the brass tube with a very fine wire. I've seen several of the float bowls clogged completely but look clean.

[yoshisakan]

Copy that - Is there a "DIP" method for the casual carb builder? Are you referring to those gallon buckets of "carb dip" sometimes found at the auto parts store?

[JTGS850GL]

Yes, one can of Berryman chem dip. The professional grade is best but harder to find and it doesn't come with the handy bucket. Here's a place I get mine from:

http://www.oreillyauto.com/site/c/detail/BRY3/0901/N0441.oap?ck=Search_N0441_BRY_-1_1326&mn=Berryman&mc=BRY&pt=N0441&ppt=C0090

I use a bucket from the more common non professional version that I purchased a couple years ago.

This is the one with the bucket:

http://www.berrymanproducts.com/products/eco-friendly-products/berryman-chem-dip-carburetor-and-parts-cleaner/

[yoshisakan]

So I went up to 45s, it will idle perfectly now and if I flutter the throttle to 1/8 or 1/4 open it revs fine, if I go to 1/2 or more it hesitates then revs and slowly revs back down when I snap it closed. Needle clip? I'm on 2 down, thinking of going to 3 down.

[yoshisakan]

Cylinder 1 is still behaving strangely. It's not heating up like the other pipes. I think maybe I need to step up to 50s, when I opened the adjusting screws to 5 turns the mid range lean lessened. I'm using those long boy fuel screws so either they're slightly different than stock or the pilots are still undersized. I don't think the needle would make it act lean after shutting the throttle .

[yoshisakan]

The problem here is cylinder 1. I can pull the wire and there's no idle change, if I pull cylinder 4, the bike dies every time. The carbs are spotless, all the pilot circuit holes I can see through. Carbs are bench synced. Put about 80psi of air in the cylinder, valves are all sealing, no oil blow by from worn piston rings. Ive switched coils and cylinder 1 and 4 wires. Electric grounds are all good. What on earth could be the problem here?

[yoshisakan]

Spark plugs from 1 and 4. http://imgur.com/63lBsRS http://imgur.com/I8nZwg1