Author Topic: plug fouling  (Read 2714 times)

Offline jfligg

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plug fouling
« on: 10.08. 2006 17:55 »
Hi guys
  I just got my A7ST out for the first time today.  Its starting to foul plugs.  Its running alittle rich.  I am going to try a hotter plug and go from there.  Last season the bike ran great but started to get a bit rough in October.  Any other ideas.  Thanks Jeff

Offline BrianDallasTX

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Re: plug fouling
« Reply #1 on: 14.08. 2006 14:03 »
Have you checked the timing and points?  It can cause a weak spark that won't burn the gas well.  How fresh was the gas?  I would think play in the throttle body of the carb would make it run leaner and very rough/uneven.

Brian
Brian
'63 A10 Super Rocket

Offline jfligg

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Re: plug fouling
« Reply #2 on: 05.09. 2006 14:44 »
Hi Guys
  Heres a plug fouling update.  I set the points, dropped 2 main jet sizes, installed a new needle jet. So its still running rich.  I am off to get a hologen bulb for the headlight so I'll get a new needle today.  I am also looking for a 276 carb to try.  The monoblock is a real tight fit.  Onwards and upwards.  Jeff

Offline BrianDallasTX

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Re: plug fouling
« Reply #3 on: 08.09. 2006 03:13 »
What plug are you using?  I currently have NGK B8ES and I am finding them a bit sooty after 100 miles/tank of gas.  I have been running 93 and lately I have noticed a bit of pinking.  Previoulsy I had B7ES and there was only slight fouling and very little pinking.  I think I may try B6ES next go round but they were out when I bought the last four.  I usually commute so the traffic could be a factor.  Let us know how it goes.
Brian
'63 A10 Super Rocket

Offline dpaddock

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Re: plug fouling
« Reply #4 on: 18.10. 2006 01:27 »
I run B5ES's in my A10 in order to get a light tan on the center electrode nose. That's the primary result you want for your riding style.

The dark and sooty stuff around the plug, is any, is the result of fuel richness, oil in the combustion space, or just plain failure to reach operating temperature because of idling, low speed, etc. It has nothing to do with the heat range of the plug as long as you're getting the nose color stated above.

Don't worry about "holing the piston" or other dire old wives tales associated with "hot" plugs, unless you're running a racing Bantam.
David
'57 Spitfire


Offline fido

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Re: plug fouling
« Reply #5 on: 18.10. 2006 11:17 »
I have 2 pairs, one pair on the head and one pair in the tool bag. I still get hot starting problems sometimes so I swap the plugs and it seems to start on the cold ones. One set are NGK B6HS, other are Nippon Denso W20FS-U. Both have the light tan deposit on the centre insulator.

Offline BrianDallasTX

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Re: plug fouling
« Reply #6 on: 22.10. 2006 16:31 »
The B7es seem to be a good choice for my sickle, and I have been using RPX gas additive.  The pinking hass all but stopped.
Brian
'63 A10 Super Rocket

Offline jfligg

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Re: plug fouling
« Reply #7 on: 23.10. 2006 17:44 »
Hi Guys I got my A7 put away for the winter know.  Next spring I am gonna try the twin 275 carb set up.  It'll be sure to be troublesome.  Jeff

Offline BrianDallasTX

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Re: plug fouling
« Reply #8 on: 25.10. 2006 03:19 »
Aw man it is finally cooling down nicely here!  Been riding as much as possible.
Brian
'63 A10 Super Rocket