No. 1 doesn't want to work

[Incubus]

Hi guys,

I've been sidelined for a while with mandatory tasks, so I haven't had a chance to let Succubus mock me for a while. Now I'm back and my XS is in true form.

After adjusting the pickup coil gap again I have good blue spark on all four cylinders. I have fuel in the bowl of carb one. I have 125 pounds of cold compression on cylinder 1. The timing on Succubus is dead on, based on my pulling the valve cover to make sure lack of drinking had not caused me to mess up the cam timing and then timing at 1,000 rpm with my light. This timing was done on the wire for cylinder 1, so there is spark there.

Succubus starts right up and runs, and Succubus idles. That is, if you can consider any of that to be true with a cold header off cylinder 1. I apparently have fuel, timing and compression and yet no controlled explosion. It's surprisingly powerful for a three-cylinder bike and I can idle at stop signs, but I want more. I want it all.

Every time I fix something, something new crops up. No. 1 has worked, but then Succubus wouldn't idle. Now it idles, but No. 1 has gone AWOL - and I have absolutely no idea why. There is some random backfiring, so maybe it works when it warms up. I dunno. I set the air screws at 1.5 turns out and I haven't messed with them yet. I don't think you can Colortune a cylinder without combustion.

Where might this lone cylinder be going wrong? It has worked before. What do I need to mess with now? Any ideas?

Patrick

[Incubus]

Update: Number one fires when I rev, just not at idle. I'm thinking I have to adjust the air mixture.....

[fredintoon]

no such luck

Patric sez:-
Update: Number one fires when I rev, just not at idle. I'm thinking I have to adjust the air mixture.....
Hi Patric,
betcha that won't work. Betcha that you have to tear down #1 carb and clean it yet again. If I have to clean & clean & clean those nasty teensy internal carb passages why should you not have to do so?
Fred Hill, S'toon.

[Ken Talbot]

Sounds lke the enrichener circuit on #1. If you're lucky, the blockage will be in the orifice at the bottom of the float bowl - the one that feeds the circuit. Being at the bottom of the bowl, it is quite prone to spooge.

[TopCatGr58]

Hey Ken,

Didn't you mean the Pilot circuit?? Once he has it running and warmed up, he shouldn't be using the enrichener, and so it shouldn't have anything to do with the fuel flow for the idle/pilot circuit?

But like Fred said, probably need to pull the carbs, and check out the pilot circuit, jets, pilot screw(which is an air/fuel mix screw, not necessarily just an AIR screw) and such cause it sure sounds like it isn't getting fuel at low rpm, only when he revs it getting into the mains!
T.C.

[Ken Talbot]

Oops - brain f@rt there. Of course it would be the pilot circuit. Might as well have a look at the float bowl orifice too on the way in....

[Incubus]

Fortunately, I can pull the carbs on this bike in about 10 minutes, especially considering that the tank and seat are already off. Someday it will be an every day ride and I won't remember how to pull the carbs. Someday. I swear.

I already have the carbs off and I have two - count 'em, two - cans of B-12. I've already put two cans of B-12 through these carbs. Maybe the next one is the charm. I have pilot jet on three, shooting for four....

Patrick

[Incubus]

One last question (for today). I've been spraying carb cleaner through the pilot jet hole in No. 1 carb for about an hour, letting it steep, blowing it out with compressed air, and then spraying it full again. I have carb cleaner blowing out through the pilot air jet in the mouth, the air vent hose, and those three little holes in the top of the intake by the butterfly.

Where esle should I get flow? Is that all the orifices or should I look for others?

[TopCatGr58]

Well, If you have the pilot screw screwed in, you won't see it, but with it out, it should also squirt up or out a bit from that as well, since it's where the metering for the pilot circuit occurs. Sounds like you've hit all the holes to me!

Oooh, how about the tunnel between the main and pilot jet towers?? I vaguely remember you mentioning about your main jet nozzle not having the hole in the right position in the end to align with that tunnel to the pilot jet, did you check to make sure that the one not firing was truly in the right position?? JAT!
T.C.

[Fredjohny]

hi,

you might also check that your sparkplug works

[Incubus]

That tunnel is the first thing that occurred to me, TC, and it's the first place I looked when I tore the carb down. The hole was correctly positioned and clear. I think it was those little holes at the top of the intake that were plugged. Hopefully this time will be the charm. It is very close to ready - closer than it has been in at least 15 years. It does idle now - on three cylinders - and once the main jet kicks it there is no problem at all. In my younger years I probably would have announced it good enough for a rider at any time during the past few weeks. My standards now are higher. It must be right.

I did take the opportunity to polish some of the aluminum. At the very least it will look good by the side of the road.

Patrick

[Incubus]

Oh, and by the way, FredJohny, the plug sparks well when I ground it to a valve cover bolt. A strong blue spark.

[fredintoon]

Yeah, right

Succubus sez:-
the plug sparks well when I ground it to a valve cover bolt. A strong blue spark.
Hi Succubus,
A strong blue spark in air is a strong hint but not a guarantee that the plug will also work under running conditions.
Swap that plug with one of the others and see if the problem moves with it. Then you'll know for sure.
Fred Hill, S'toon.