High & inconsistent idling with backfiring

[equinox1216]

Well my bike was doing so well for years. After sitting over the winter, having been run MOST weekends) it almost wouldn't start and when it did, it backfired badly and wouldn't idle.

So far I have had a couple mechanics look at it. The carbs were removed and adjusted, and re-installed with the original air filter system (it had a custom system before).

Now, started cold it idles at 5k and backfires a lot. Once warmed up you can coax the idle down by putting it in gear with front brake on and easing out the clutch.
Then the idle will hover around 1.5k until you do ANYthing with the throttle, then it's back up to 5k again.

Any ideas why it might be backfiring and idling so high?

Note: When I trick the idle into a reasonable zone (1.5k) it runs really well, with minimal backfiring.

[equinox1216]

Forgot to mention another possible clue.

Starting the bike cold about 8 times since carb work I noticed that a few times I started the bike with choke on and the idle was where it was supposed to be.

While warming up the idle became unstable and inconsistent... jumping up to 5k on a whim...stalling... not reacting to choke settings...

[crazy steve]

Have you done a carb sync on the bike? If that hasn't been done, that's the likely culprit...

[Fearthepack]

I had the same problem after cleaning the carbs. I had to back out my idle screws (3) of them a turn and a half just to bring the (1) large headed idle screw into play. This fixed mine an enabled me to then sync the carbs. My conclusion was my idle was set way high with dirty carbs just to get it to stay running, once cleaned it would climb from 1500rpms to 5000 rpms with no throttle until i would race to turn the key off.

[ManagerMike]

Carb sync. or maybe a split vacuum cap on one or more of the sync ports.

[equinox1216]

Thanks for everyone's input

I appreciate all the info.
I will have to get an answer from the mechanic before I can answer some of these questions.

[Diskman01]

All of my bad running issues were fixed by finding ALL the leaks (sync port leaks), and a good carb sync.

[equinox1216]

Unsure of my mechanical abilities

I found a place semi-locally who will clean, check, bench-sync the carbs for $30 if I bring them in. Of course that means I have to remove them from the bike.

I realize a lot of you guys do this without thinking twice about it.
My life has been spent in the world of computers and, though I can diagnose or rebuild just about any computer, I have to hesitate when I look at the carbs assy.

I watched a couple videos on youtube showing the removal of the carbs. None of them really showed a step by step, but I got the general idea.

Think I should try it? And, if so, what are the odds I can get it back onto the bike again? (I mean correctly) lol

[crazy steve]

I found a place semi-locally who will clean, check, bench-sync the carbs for $30 if I bring them in. Of course that means I have to remove them from the bike...

$30???!!! Does the guy answer to the name of 'Cheeta' and accept payment in bananas??

[equinox1216]

$30???!!! Does the guy answer to the name of 'Cheeta' and accept payment in bananas??

Really... I was surprised myself, after seeing what most people charge.
But as I understand it, it is done by a guy who does it for extra income aside from their regular repair service.

[bikerphil]

Better hope he doesn't bust things up in there and make matters worse, lots of delicate parts, good luck!

[crazy steve]

You pay peanuts, you get monkeys....

[DGXSER]

I have pulled the carbs of the XS so many times, I think I can do it blindfolded while sleeping. There is very little you can screw up really.

I think PlaneDick did a video once of removing them.

If you still have the Octy, the fuel lines get a little tricky, but still nothing to bad.

Step 1, remove the seat, two long bolts underside of seat.

Step 2, remove the tank, one bolt at the back of tank, lift it up (I like to put a roll of handy duct-tape under the tank flange where the bolt goes through to keep it elevated), remove the fuel lines form the petcocks, and lift the back of the tank and slide it back then lift the tank up.

Step 3, remove the vac advance from the nipple on carb no 2.

Step 4, disconnect the throttle linkage form the carbs and pull it up out of the way.

Step 5, pull the clutch cable out of the clip on no 4 carb.

Step 6, remove both side covers, and remove the two 10mm bolts that bolt the airbox to the frame, one on each side.

Step 7, remove the top 10mm bolt that holds the airbox to the frame, just in front of the gas tank mounting point.

Step 8, get a long handled philips screw driver and loosen all eight clamps holding the carbs to the intake boots, and the air box boots.

Step 9, loosen all four wing nuts under the airbox, and remove the lower section of the airbox.

Step 10, pull the upper section of the air box backwards off the carb inlet bells. I like to use a small screwdriver to put in the hole that lst upper 10mm bolt was in after pulling the airbox back to hold it back.

Step 11, grab the carbs and pull them backwards out of the intake boots. I do this with a slight up and down rocking, and pull the back of the carbs up over the inlet boots of the air box. Once loose from the intake boots, I like to slide them out the left side of the bike. You will need to manipulate the throttle linkage around the oil tube running up to the head.

You now have a set of carbs in your hands. Putting them in is just the reverse. Hint, I like to spray the intake boots with WD-40 helps the carbs slide into the boots easier. Also, when putting the airbox boots back on the carbs, I work number one on first, then tighten the clamp on the boot, gor around to number four and work it on good and tight and tighten its clamp. Then I work on the inner two which are 90% on after the outer two are in place.

Hope that helps you.

[ManagerMike]

Reach down, gird your loins, and tackle it yourself. There is ample info on this site for one with technical and logical capabilities to come to grips with these bikes.
All told, they are quite simple, once you learn thier pecadillos.
What you will learn about the bike (and yourself) will give you an incredible sense of accomplishment and a desire to challenge yourself outside of your comfort zone again. If you run into trouble, the folks here won't hesitate to help.
Just take it slow, do one carb at a time your first time through. If you get confused as to where a part goes (or came from) there are three identical ones right there for reference.
Consult 'carb cleaning 101' in the tech forums to get a gist of what you can expect to encounter, and you do not need to separate the carbs from each other, just open them up one at a time.

[DGXSER]

Reach down, gird your loins, and tackle it yourself. There is ample info on this site for one with technical and logical capabilities to come to grips with these bikes.
All told, they are quite simple, once you learn thier pecadillos.
What you will learn about the bike (and yourself) will give you an incredible sense of accomplishment and a desire to challenge yourself outside of your comfort zone again. If you run into trouble, the folks here won't hesitate to help.
Just take it slow, do one carb at a time your first time through. If you get confused as to where a part goes (or came from) there are three identical ones right there for reference.
Consult 'carb cleaning 101' in the tech forums to get a gist of what you can expect to encounter, and you do not need to separate the carbs from each other, just open them up one at a time.

Generally speaking Mike, I would agree with you, but for $30, crap you might spend that in carb cleaner getting them cleaned up.