Black Sooty Plugs - Ignition Timing or Carb issue?

[a101960]

You are right. Slapped wrists I have not been paying attention, as you say you have a manual set up. None the less when you time it, the mag must be on full advance. As others have suggested you will need a puller. The same caveat applies to setting up. The wheel will probally creep and in so doing will alter your timing. It is very useful to have an assistant when doing this job

John

[Brucie64]

OK, just ordered a 260, 250 and 240 main jet for the carb (currently running a 270), will do some plug chops & tests with these next week to see if I can stop the dreaded sooty plugs. Thanks for all your help again guys this weekend.

Bruce

[a101960]

Well, with the assistance of Richard from Minety I had another go at the timing this afternoon. Using the Independent Ignition timing light it was set up to 35 degrees fully advanced and the bike pulls very well, and there is no pinking, so a satisfactory result.

John

[chaterlea25]

HI Brucie,
The main jet size will only make a difference at 3/4 to full throttle
Make sure that the pilot jet is fully tightened before the cap nut goes on
check the fuel height in the carb, there are a couple of ways of doing this covered in the posts here
I like the little plastic tube over the pilot jet, brought around the other side of the carb to line up with the mark on the float chamber cover.
Once I had a problem like this and it turned out to be the wrong type of needle jet fitted, it had no cross drillings for the atomising air!!
Regards
John O R

[cus]

G'day Bruce,
In the first post ypu mention that you changed the needle pos. from 3 to 4,
I think that would make it richer, try 2, thats from the top.

regards, Cus

[Brucie64]

Hi Cus,

  Oh, I thought if I dropped the needle down from 3 to 4 (i.e. moving it closer to the main jet) that it would make the fuel mixture leaner. Have I got this the wrong way around and should I be moving the needle up away fom the main body of the carb to lean up the mixture?

[cus]

G'day Bruce,
If No.1 notch is on the top of the needle & the clip is around this notch, the needle would be in the lowest position, as you go
down the notches the needle comes up,
Cus

[Brucie64]

Hi Cus,

Yeah, thanks for the update. I think we are actually talking along the same lines, I just got my idents the wrong way around. I thought that if the needle was in the lowest position in the carb housing then it must be position 4, in fact as you quite rightly pointed out it is indeed postion 1. Either way it is definately in the lowest position and as such the carb is as lean as it possible with the jet configurations I currently have.

[Brucie64]

As mentioned earlier, I have had a play with the carb again today. First I checked and adjusted the pilot jet and air screw as per the manual for correct idle.  I then dropped the main jet size from a 270 to 260, this made a slight improvement to the sooty carb syndrome so decided to drop again to a 240 main jet and raised the needle from pos 1 to pos 2.
Again this improved the colour of the plugs to a somewwhat more agreeable greyish as opposed to chimney black as before!. However in doing so I have now noticed something else.

My right hand cylinder plug is noticeably more sooty than the left, this is also apparent at the end of the exhausts where the right hand one is still sooty and wet but the left is nice and dry.

Could anyone please tell me what cold cause this mismatch when only have one carb, am I looking at a valve issue?

[groily]

sounds like induction bias unless there is something more seriously amiss or the soot is actually oil. Lots of discussion hereabouts - and also links to vendors - of the 'bias washer', a flange gasket which angles the carb towards the leaner cylinder a few degrees and allegedly reduces the problem. But sounds as if you're making good progress on the original problem . . .

[RichardL]

My right hand cylinder plug is noticeably more sooty than the left, this is also apparent at the end of the exhausts where the right hand one is still sooty and wet but the left is nice and dry.

I don't think I have the carburetor mixture troubles that appear to be the crux of thIs topic. However, I do have the exact same conditions described above, except, my left plug is not sooty, but the correct chocolate brown. I have been attributing the oily right exhaust and sooty caked plug to a leaky valve guide (minor enough to be a winter project). The bit of bluish smoke on the right would seem to confirm this. Is it possible that, all along, Brucie's sooty plugs have been due to leaky guides, or is my wet pipe due to something else? Or, maybe a combination thereof?

Richard L.

[Brucie64]

Induction Bias.....ok, I have heard of this (basically from trawling through the old posts on this forum), is the acquistion of this bias flange a stopgap to make ends meet till the crux of the problem is really tackled i.e. head off and valve's sorted during the winter months?

[RichardL]

Bruce,

My point was that I didn't think your's or my oily right pipe was due to induction bias. Actually wish it were, as it would be a whole lot easier and cheaper to fix than valve guides.

Richard L.

[Brucie64]

Hi Richard,

Just ordered a "bias induction" flange, I will keep you posted as to the outcome as soon as. I agree with you however that the issue is more than likely a valve guide problem and the flange will only probably be a short fix.

[Josh Cox]

Brucie,

Orabanda has a post running, "dyno dyno on the wall", you might find yourself intimately interested in his findings, the bias spacer may help, but it might be a timing issue ?, these magnetoes are primitive at best.