Idle too rich?

Let the bike sit for a week and it won't start.

The exhaust keeps backfiring, so I pretty sure fuel is getting to the engine.

Checked the spark plugs, the one I pulled fired only sporadically when I pushed the starter button.
They are definitely black, maybe a little buildup. but I don't really know what's normal.

While riding the bike I'd hear a strange sound, kind of like a chicken clucking, especially when I wasn't giving the engine gas. I checked for poultry in the tank and carbs, no feathers or anything.

So my theory: idle mixture is too rich, there's carbon buildup on the plugs, keeping them from firing reliably. Clean the plugs, turn down the idle mixture.

Comments?

Also, what's the proper tool for cleaning up a spark plug? I was thinking a wire brush of some kind.

 

hahahah was it kindof a goose sound? ya know honk honk? do you get a small burp out the carbs ever? its kind of hard to see unless you have pod filters i suppose but mine was backfiring and burping all over the place and i had to adjust valve clearances because the valves were floating just a touch. your spark plug read does sound like your running a bit too rich but i wouldn't mess with the idle mixture screws just yet until you've checked your valves thats just my 2 cents.

 

Cool, cool. Guess I'll check the valves. Never done that before, should be fun.

 

Don't clean the Plugs ... Install a set of new ones and start keeping a Log on where your Pilot Mixtures are set.

Adjust the Mixtures with a Colortune Plug if you can find one to borrow or rent. Since its such a valuable asset to tuning I recommend you buy one.

If you can get a hold of a Colortune Plug ... adjust the Mixture screws to a few degrees short of 3 Full Turns Out.
Run the Bike.
Read the Plugs after a few hours of riding.
Make individual adjustments to each Mixture Screw Enriching or Leaning the Mixtures as needed.
Keep the Idle as close to 1,000 rpm's as possible.

Test the Mixture by opening the Throttles.
If the Engine Boggs-down before revving-up ... you're too Rich.
If you Backfire or stall-out ... you're too Lean.

Don't OVERADJUST the Mixture Screws.
A degree or two is all that is needed to change the Mixture from Lean to Rich and vice-versa.

 

I've managed to foul plugs when I KNEW I was lean. Reason is start with choke, move a few feet, turn off. I was able to resurrect spark plugs by giving them a quick squirt of starter fluid. Put them back in, fire up.

 

Hmmm. Funny you should mention that. The last time I turned on the bike was to show my brother the bike. Actually, he turned it on, in the shop, in the cold (thus with "choke" open), went twenty feet, then killed the engine. And off we went to eat some twinkies, or something.

The spark, very strange. It doesn't make it across the gap, on either of the two plugs I checked. Just little spots of electricity. Occasionally it gets a spark to arc all the way across - hence the occasional firing of the cylinders, I guess.

Tomorrow I'll replace the spark plugs. But is it possible my coils are a little weak, too?

 

Interestingly, when they are fouled they are more likely to fire when they have a poor ground. This is probably what you are seeing if you've just laid them against the engine like I do. I guess a real man would hold them, but I just don't xxK volts all that much. Too much thrill at my age.

 

Naw, I'm a real man. I hold 'em.

 

You have to determine if its an Ignition Problem or a Fuel Problem or both.
If you still have the original Fuse Panel ... I'd recommend you replace it.

If the Plugs are fouling because the Mixtures are too Rich ... wew can deal with that easily enough.

Do your resistance checking.
See if you have good Spark.

If you do we have to work on Mixtures and Carb issues.

 

Okay, got new spark plugs, and the engine fired up great. It was hard to tell exactly using your throttle test, Rick, but there wasn't any backfiring and there might have been a little hesitation when I revved. So I went with my instinct and went a little leaner on the mixture.

Rode an hour or two around the hills. The clucking sound (seriously) also seemed to have disappeared, so I guess it had something to do with the mixture, too.

Can't afford a colortune right now, it's high on the list, though. Them things sound handy.

Thanks again, fellows.

 

If its running "Pretty Good" ... start a Tuning Log.

Make where it is at the moment Zero, zero, zero, zero.

After a few days of riding ... and certainly after any highway riding ... take a peek at the plugs.

Lay them out 1 - 2 - 3 - 4
Look at the Burn and look at the Ceramic surrounding the Center Electrode.
After you have examined the Plugs ... determine which Cylinder needs to be made more RICH and which might need to be Leaned-out.

Make Tweaks ... 2-Degrees at a time!

A new Tuning Log entry might look like this.
1 is Rich
Tweak #-1 IN -- 2-Degrees

2 is OK
Leave alone.

3 is too Lean
Tweak #-3 OUT -- 2-Degrees

4 is too Lean
Tweak #-4 OUT -- 2-Degrees.

The New Entry looks like this.

Minus 2 -/- Zero -/- Plus 2 -/- Plus 2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
To return to the Base value ... you reverse the Tweak.

Next Plug Read
____________________

Rich -/- OK -/- OK -/- OK

-2........0........0........0

Next Read
______________________

0........0........0........0 All OK

Begin Performance Tweaking:

Acceleration and severe engine braking:
Minus 2 across the board. Leaned-out but not critically lean.
Plug is clean.
Ceramic is clean and not showing micro-fracturing from being too hot.

Cruising and Long Distance Riding
Return to Zero ... across the board.
Plus 2 -or-3 for Rich Mixture

Be a Tweaker!
When the Anti Tamper Plugs are drilled-out ...
You get to play with the screws if you want too.

 

A good system, methinks. I will start today.