Can't Seem to Get My Carbs Right

[SovereignDragon]

Ok, first off we are talking about a 1980 Standard. I can't see any passages from the mains to the pilots so that leads me to believe I don't need the rubber plugs. I have pod filters and have cleaned my carbs 4 times. I first soak them, completely disassembles, in my small sonic cleaner and then go about cleaning by hand to make sure they are good. It wants to fire right up with the choke all the way on. It will run for about 20 to 30 seconds but it pops through the exhaust. I pulled the plugs and they look like they are damn near fouled out like they are getting too much fuel but it is running stock jetting. Also I noticed the plugs for cylinder 1 and 2 are dry while 3 and 4 are fuel soaked. After it runs you can't touch the pipes on 1 and 2 while 3 and 4 are only warm to the touch. Also number 3 seems to have more soot built up and blowing back out the intake side of the carb. Sorry if this seems like I'm rambling but I've given up for the night and gone inside to talk to my good buddy Evan Williams about the issue. He just keeps telling me my glass is empty. Any help would be awesome guys and if you need anymore info on my end just let me know what you need.

[motoman]

Ok, first off we are talking about a 1980 Standard. I can't see any passages from the mains to the pilots so that leads me to believe I don't need the rubber plugs. I have pod filters and have cleaned my carbs 4 times. I first soak them, completely disassembles, in my small sonic cleaner and then go about cleaning by hand to make sure they are good. It wants to fire right up with the choke all the way on. It will run for about 20 to 30 seconds but it pops through the exhaust. I pulled the plugs and they look like they are damn near fouled out like they are getting too much fuel but it is running stock jetting. Also I noticed the plugs for cylinder 1 and 2 are dry while 3 and 4 are fuel soaked. After it runs you can't touch the pipes on 1 and 2 while 3 and 4 are only warm to the touch. Also number 3 seems to have more soot built up and blowing back out the intake side of the carb. Sorry if this seems like I'm rambling but I've given up for the night and gone inside to talk to my good buddy Evan Williams about the issue. He just keeps telling me my glass is empty. Any help would be awesome guys and if you need anymore info on my end just let me know what you need.

First remove ignition cover, and using both hands stretch every inch of those pick-up coil wires. If one is broke internally, the insulation will stretch If broken wire internally found, repair using a really short piece of butt connector(non-insulated)crimped on, with a shorty piece of shrink tubing installed over repair( I advise NOT to solder repair). Next, unscrew plug boots from each wire and cut back each wire a quarter inch and screw plug cap back on. These are common issues, and a good place to start in order to resolve issue.

[SovereignDragon]

I didn't feel any stretching in the pickup wires. It did seem to help a little taking off the tip of the ignition wires though. There was hardly any copper left to make contact on the end. The bike is still popping and shuts itself off and the exhaust pipes for 3 and 4 are only warm to the tough, but will now run with the choke on the middle setting and completely off. I did forget to mention the needles have been shimmed. They had 1 very thin washer each and while fighting this I have added 3 more to each needle. The idea was that it was running lean due to the pods and they were added to richen the mixture.

[motoman]

Well, for starters associated with that, remove ALL those washers. You may have to go up one step with the pilot jets(Genuine Mikuni with the stamped in logo) from 42.5 to 45 pilot jets. The washer stunt is INCORRECT way of solving lean issue! Those metering rods are by design, to work correctly as they come, height wise and all, unless mods demand one step richer with pilot jets.

[SovereignDragon]

I will definitely try that tomorrow. I live in a quiet neighborhood and don't want to piss off the neighbors any more than I already do. My typical daily drivers are a ducati monster 696 with homemade baffles for exhaust and a supercharged grand prix with no resonator and cherry bombs. Oh yeah, and I leave at 620 in the morning. I will report back tomorrow night once I pull the shims and fire it up.

[motoman]

I will definitely try that tomorrow. I live in a quiet neighborhood and don't want to piss off the neighbors any more than I already do. My typical daily drivers are a ducati monster 696 with homemade baffles for exhaust and a supercharged grand prix with no resonator and cherry bombs. Oh yeah, and I leave at 620 in the morning. I will report back tomorrow night once I pull the shims and fire it up.

All good....thanks for reporting back. Least that'll tell you whether or not the pilot jets need jumped up one size.

[dansmith65]

Is the left and right bank of carbs severely out of sync?

It's purely consequential, but a 1984 XJ750RL I recently bought would barely run, then had similar symptoms with left/right exhaust and plug fouling. It turns out it had two different sets of plugs in it! I'm not suggesting you have two different set's of plugs, but maybe two plugs are bad, or not getting spark, etc. You could get out a multi-meter and check your plugs to help rule this out.

[motoman]

Is the left and right bank of carbs severely out of sync?

It's purely consequential, but a 1984 XJ750RL I recently bought would barely run, then had similar symptoms with left/right exhaust and plug fouling. It turns out it had two different sets of plugs in it! I'm not suggesting you have two different set's of plugs, but maybe two plugs are bad, or not getting spark, etc. You could get out a multi-meter and check your plugs to help rule this out.

Better yet, multi-meter and check across poles of each coil. They each need to be 1.5ohm on that 80 model. If down two or three tenths,,replace coils with new.

[Joe Bartelt]

This does not sound like ignition to me. The coils are strung between cylinders 1-4 and 2-3(Corrected). if it was a single ignition coil or pickup coil that was causing the problem it would manifest in these cylinder pairs, not 1-2.
However your fuel petcock's are linked to carbs 1-2 and 3-4(Corrected). I would check to see if the left petcock has fuel coming out. Try putting both petcocks into the "PRIME" position then start the bike and see if it does the same thing. If it still runs lean on cylinders 1-2 try pulling both fuel lines and confirm that fuel is coming out of the tank on each side.

[TopCatGr58]

Hey Joe,

Nice try, but a few mistakes, I have corrected them.

Hey Dragon. Okay, Pod filters....are they the inexpensive EMGO cone shaped type? If so, they have a prominent lip on the mounting that interferes with the carb inlet bell ports and been known to cause excessively rich conditions.

See this tech tip about them, and some mods on mounting them.
http://www.xs11.com/forum/showthread.php?t=8269

Next, sounds like you've done a good job at cleaning them, using Sonic cleaner, disassembling them, but we still have to ask if you actually pulled out the main jet needle/emulsion tubes and cleaned. 1-2 are dry plugs and pipes HOT, so sounds like they are actually working OK. 3-4 are WET and just warm pipes.

You say STOCK jetting, but not verified TRUE MIKUNI jets vs. aftermarket. THey can be named/marked same size, but are metered wrong/different from Genuine Mikuni and usually much larger=richer, both mains and pilots.

Good start on snipping plug high tension wire ends to get to good copper. Other points, like Motoman said, the PRIMARY resistance for each coil measured thru the HARNESS wire end/connector should be ~1.5 ohms. Also check the resistance on the PLUG wire ends, remove caps, should be ~15K ohms plug wire to wire for each coil. Another spot for loss of spark energy is the caps. They are resistor, measure thru from wire end to plug end, should be only ~5k ohms, if much higher, you can take apart cap from the plug end with screwdriver, remove internal spring/resistor, measure resistor, clean, remeasure, replace if still too high. Have seen poor spark on the 3-4 pairing due to excessive resistances and poor primary voltage, so has enough juice to fire the 1st plug of the pair, but after running thru plug, engine head, and then back up thru the other plug it runs out of KV and can't complete the journey=poor/no spark=wet plugs=cool pipes.

Keep at it. T.C.

[DiverRay]

Did you replace the "O" ring in each seat? TC is correct about the pods, you MUST make sure they don't infringe on the bell, as the vent or air jet can be blocked, causing a "flooding" condition, black plugs and no spark.
Also, VERIFY all floats are at the same height. As I said in another post, with the bowls removed secure the carbs UPSIDE DOWN on something( I use a 2X4 and a "C" clamp in a vise) and feed fuel to them. Let it sit for at least 3 minutes to verify NO LEAKS.
Problems being 3&4 are carbs, NOT Ignition, IMHO

[speedlimit85]

First remove ignition cover, and using both hands stretch every inch of those pick-up coil wires. If one is broke internally, the insulation will stretch If broken wire internally found, repair using a really short piece of butt connector(non-insulated)crimped on, with a shorty piece of shrink tubing installed over repair( I advise NOT to solder repair). Next, unscrew plug boots from each wire and cut back each wire a quarter inch and screw plug cap back on. These are common issues, and a good place to start in order to resolve issue.

Why do you recommend crimping rather than soldering?

[jetmechmarty]

Why do you recommend crimping rather than soldering?

A proper crimp is a more durable connection. That doesn't mean a crimp done with a pair of pliers.
https://youtu.be/pZ809uTlENE

[motoman]

Why do you recommend crimping rather than soldering?

Those particular wires always have movement. The heat from soldering them together changes composition of copper, weakening it. This can cause a re-peat of wire breakage right next to solder joint.

[SovereignDragon]

I know I disappeared for a while. Winter came and I work 7 days a week so I just stopped messing with it. I'm back at it. Today I double checked my valve shims and timing. 3 and 4 intake were a little loose so I got those back into spec. I'm going to pull the carbs..again...since it was sitting and go through them. As for the jets yes, they are mikuni jets. Also I took the pods off just to try to get the damn thing to run better, just running open air box. I might just try to ebay an airbox for this thing and stay away from the pods. They did have a lip but I shaved them off before originally mounting them. Also gonna check resistance through the coils soon. Hopefully I can make some headway on this bike. I really don't want it to just rot away, these bikes are awesome powerhouses.