Topic: Odd timing issue, the closer to F the worse it runs.

[Jore]

Well they are all even, that's good.
They will soon misfire with that amount of carbon build up.  Not so good.
What's the run time/regime on those plugs?

Give us a carb jetting review/status?  I haven't looked back through the tome.

I've run those plugs for maybe 20 minutes before I took the pictures, before that I had them cleaned with a sandblaster and had run them probably an hour or 2 tops. Thing is even if I put new plugs on the bike, they will get like that within a couple of minutes.

I'm running #75 mains and #40 slow jets, air screws are 3/4 of a turn out.
Going through some rebuild kit pictures it seems there's an o-ring that goes on the airs crews, my carbs don't have them.

EDIT: I'm running the stock airbox with stock air cleaner, carb boots are about 2 years old and still pretty soft, as for hold downs i'm using hose clamps since the original honda clamps where nowhere to be found when I got the bike, I've sprayed the carb boots numerous times while the bike is running with carb cleaner and haven't notice anything with the idle speed, so I'm guessing there's no leaks.

[TwoTired]

How old is the air cleaner?
What happens if you turn the pilot screws outward?
What slide needle position?

[Jore]

How old is the air cleaner?
What happens if you turn the pilot screws outward?
What slide needle position?

-About 2 years old, but I started using probably 2 months ago when I fired back up the bike, it's still fairly clean and white.
- If I play around with those the idle speed changes
- Third from the top down, so factory setting.

[Jimray23]

Looks to me like your running rich

--------------------------------------------------
Jim
1979 kz1000b ltd
    stage 3 cams
    pod air filters
    4-1 open exhaust(no muffler)
    full rewire
    dyna-s ignition
    dyna 3 ohm coils

[Deltarider]

For a test try with the air filter element removed.

[Jore]

Looks to me like your running rich

This got me thinking last night, since my air screws are only 3/4 of a turn out that would make the bike idle really rich, I left them at that setting because that made the idle go down a lot, if I left them 2 turns out, idle speed was around 3 k, but when I fiddled with those settings, the carb slides weren't seating fully in the bore and had a gap left from setting them with a drill bit.

So on the next test I'll put the air screws out to 2 turns, check the plugs, and then do another test without the air filter.

[Jore]

Got some idle chops done, I used media blasted plugs for this, here are some pictures of what they looked like before:



After idling for about a minute with the screws 2 turns out:
Left to right if you're looking at the bike from the front



Different set of plugs, same amount of time but 2.5 turns out, same deal left to right from the front of the bike:



So from this test I can infer that the cylinder above the points is richer than the other 3, so a clear tube test will be performed. Also the dead cylinder is still acting up under 2k rpm, so it has something on the slow speed circuit.

I still need to resync the carbs and check timing.

[Jore]

After a short jaunt around 6k long, and trying to rev the bike as much as possible, there's no top end on the bike, i got up to probably 90 km/h going downhill, she didn't struggle as much this time and the motor only died once I was parked in my driveway waiting for the garage door to open.

I took the plugs out and this is what they look like:

So i'm running rich or some other thing is wonky

[flybox1]

Hey, these idle plug chops look good.    Make sure ALL 4 are this color, and make mixture screw adjustments till they are.


Skip the 6k rpm riding for now.  Your close, so follow this to tune out the richness.
You need to move to a 1/4 throttle plug chop.  The plugs SHOULD come out close to these ^^
(Make/tape an index mark on your Right control.  Tape a mark on the throttle grip next to the control mark to indicate ZERO....turn the throttle and mark 1/4, 1/2 and 3/4 throttle positions.  This will help you SEE what throttle position you are in while riding.)

If the 1/4 plug chop comes out with good color, proceed with a 1/2 throttle position plug chop.  This tests needle position.  If your richness is introduced here, you'll need to make needle clip changes, moving the clip towards the blunt end of the needle.

After the needles are in the right clip pos, go to 3/4 chop and test for main jet ..

[Jore]

Should the 1/4 chop be done riding?

[flybox1]

Should the 1/4 chop be done riding?

Yes.  Uphill is even better with the bike under load.
Gear makes no difference.  Maintain the slide height as best you can for the duration, and then cut the engine.
Coast/brake to a safe place...pull your plugs to have a look.

[Jore]

Should the 1/4 chop be done riding?

Yes.  Uphill is even better with the bike under load.
Gear makes no difference.  Maintain the slide height as best you can for the duration, and then cut the engine.
Coast/brake to a safe place...pull your plugs to have a look.

Thanks I'll give it a go

[Jore]

I tried the 1/4 throttle chop, I used new plugs, here's the before and after:



The cylinder with the cleanest plug was firing, same exhaust temp as the other 3, so what could be the issue here? I'm guessing the 2 outers have something to do with the floats, the inners seem better, but the cleanest cylinder is pulling a bit less vacuum then the other 3.