#1 cylinder problem

[airborneXS]

before i start taking things apart, i wanted to get some info. heres where i am.
Ive noticed that the bike doesnt run 100%. Upon start up, only 2,3, and 4 header pipes get hot. #1 gets warm, but i can hold my hand around it. The pipes are wrapped. While riding, ive been riding it for awhile, it appears to get peppier after 3500 rpms or so. It is getting spark, not sure if its weak or whatever. After riding for a few mins, the pipe feels hot. Took out the plug, it doesnt seem wet from fuel. so am i having a carb issue or a spark issue? or both...im going to check the floats. when i rebuilt the carbs with the bigger jets, i forgot to mess with the slide needle. All i did was take them apart, lightly clean them, then replace the main and pilot jets, is there anything else i was supposed to mess with in there ( the PO said he had already rebuilt and cleaned them, not sure how far he went with it )

[JasonRedbeard]

Pull the bowl off the carb that isn't firing at idle and make sure the little hole in the bottom of the bowl flows freely to the slot in the bowl flange. That little pressed in jet is critical for idle and off-idle operation, and from what I hear they're commonly overlooked during the cleaning process.

That's where my problem was when I had one not hitting at idle, but kicking in around 2500-3000.

[ViperRon]

define the area of problem

Sounds more like fuel but if you suspect a firing problem swap the wire going to 4 over to 1 and 1 to 4 swap the plug also if problem moves to cylinder 4 then its a firing problem. You can also check compression on cylinder 1 when the plug is out as if the bike sit for some time and either of the valves were open on cylinder 1 then it may be sticking some or have a carbon deposite. If either valve sticks open a little at Idle and low speed you can have no power as it will not even suck in fuel. When the RPM's are up the vacume increases and you get more fuel into the system. All you need to do is press a finger over the open spark plug hole and if pressure pushes it out you have compression enough that its not causing this problem. Swapping wires checking compression are simple and much less work starting off than looking at a carburator to start off. It will define for sure the problem is Fuel system, Engine, or electrical.

[airborneXS]

ok, as soon as i have a moment i will check that....ill let you know...

[airborneXS]

havent compression tested the bike with an actual tester, but when i put my finger over the hole it tried pushing it out....

[ViperRon]

Ok you have a defined carburator problem here is a link to the great picture write up on carbs that one of the other talented people here did. You said that 2,3,4 are running so as long as the jets are the same in number 1 then you should be able to go threw the cleaning and adjustment and find the issue. I'm betting you have a port clogged. Also do not overlook the T that connects the carb's .
http://www.xs11.com/forum/showthread...b+cleaning+101

[SFerinTEXAS]

Pull the bowl off the carb that isn't firing at idle and make sure the little hole in the bottom of the bowl flows freely to the slot in the bowl flange. That little pressed in jet is critical for idle and off-idle operation, and from what I hear they're commonly overlooked during the cleaning process.

That's where my problem was when I had one not hitting at idle, but kicking in around 2500-3000.

Contrare, the jet in the bowl only supplies the choke (enrichment) circuit

Definitely sounds like blockage in the pilot circuit.

[airborneXS]

still learning carburetors. what would i do to clean the pilot circuit? in other words, can you give me a step-by-step once i get the carb off the bike?

[crazy steve]

The carbs on these bikes need to be clean, so if there's any thought that you've still got crud in even one, I'd re-clean the set.

Otherwise, you may just be doing this again... and again... etc....

[BA80]

Take the idle mixture screw out and look at it. It sounds like you may have one with the tip broken off.

Pull the screw out and look at it. If it has a blunt end the tip is broken off and stuck in the idle port.

[ViperRon]

http://www.xs11.com/forum/showthread...b+cleaning+101

I sent this link before it is a great write up you may have missed it. Do each step like Steve said do them all do them right the first time. The more times you take them appart the easier it is to create a problem. Just take time do one at a time and that way you can put the carburator problems to rest and work on the other things.

[skids]

Did you balance the vacuum ("synch") the carbs after doing that carb work? If not, you should. Of course if you have an idle screw tip broke-off and stuck in the oricafe, that will not help.

[SFerinTEXAS]

still learning carburetors. what would i do to clean the pilot circuit? in other words, can you give me a step-by-step once i get the carb off the bike?

This does not answer your exact question but is how you see if it is clear.

You asked about the pilot circuit.this is my explanation.air jet(removable) is in the rear of the carb. air comes in.

fuel is pulled up thru the pilot jet and mixes with that air.comes out the upper carb bore thru 3 small holes where the butterfly closes at the top of the bore and also the mixture screw port nearer the front of the bore.

take carb spray with a straw and inject into the pilot jet (removed) cavity with a finger closing off the air jet intake. With the butterfly wedged open and the mixture screw closed down look for the 3 bore ports to deliver a steady output of spray., with the mixture screw backed out (if not broken with the tip lodged in the front port) all 4 will stream spray.. good stream means all clear

[SFerinTEXAS]

Added note: The mixture screw is the tweak (adjustable jet) for setting the sync

Hope this helps.

[cywelchjr]

Added note: The mixture screw is the tweak (adjustable jet) for setting the sync

Hope this helps.

Well, it's one piece of the process for setting the sync. While you need to set the idle mixture as part of the sync process, the actual sync is the adjusting of the butterfly valves between the carbs so that they are providing the same amount of fuel and air to each of the cylinders, ideally at all throttle settings.

So the mixture screw while a part of the process, is just one small (albeit important part) part of the process, the FIRST part of the process.