cold plugs

i'm currently running ngk b10es plugs, up from the stock b8es's, higher the number the colder the plug.

problem is that the local idiots cant find them any colder than 10 and they are glowing red hot under mild acceleration when warm.

doe anyone know of a plug colder than 10?

the lower the number the colder the pulg, you are running 2 up hotter plugs, may be causing some preignition

on ngk's the higher the number the colder the plug..might be different on other brands but ngk's run higher the colder..

if your plugs are glowing red hot i would first ask, WHY?Please be carfull running it like that.how do u know they are red hot?
i see u have new carbs.
are u jetted right,is timing right?
Something sounds off.
have u tried to richen the mix? this will help to cool the cyl.also retarding the timing.

Post edited by: mark1122, at: 2007/09/06 09:01

your right, wrong plug mfg, had it in my head from the race car plugs, got to run cold ones for the high constant high rpm

mark1122 wrote:

if your plugs are glowing red hot i would first ask, WHY?Please be carfull running it like that.how do u know they are red hot?
i see u have new carbs.
are u jetted right,is timing right?
Something sounds off.
have u tried to richen the mix? this will help to cool the cyl.also retarding the timing.<br><br>Post edited by: mark1122, at: 2007/09/06 09:01

Concur with above by mark1122.

Per FSM, plug heat range should not go more than one step in either direction.

Motors usually don't overheat for no reason.
Any ideas why this is happening?


Some possible reasons for overheating are:

Engine performance modifications

Defective oil pump or screen clogged

Oil level too low or too high

Spark plugs bad or maladjusted or wrong heat range

Ignition timing maladjusted

Float bowl fuel level too low

Main jet clogged

Carb holders loose or cracked, loose carb clamp

Air cleaner poorly sealed or missing, or duct leaking

Clutch slipping

Brakes dragging

Compression excessive from carbon build-up



Good Luck toward resolving the overheating problem.

i have performance modifications, see siggy.

good oil pressure

full on oil

i'v been playing with the ignition seeing if it will run cooler

i am having issues with the jets, exhaust popping on decel


fresh carb holders and pods.

and 178psi on a 1400 mile 1170cc rated at 10.25:1

i had speed glazing on the stock plugs, its a yellowish tint with no resedue on the tips.
under acceleration when hot it misses, gets worse with lower octane and the hotter plugs.

from what you saw on the plugs, it sounds lean, what happens if you add just a bit of choke to it to fatten it up

i agree with ksk650.it sounds lean. if u reinstall your baffle it will richen slightly as well. ar u running bs or rs 34's? what jets are in them? pilot,pilot air screw setting, needle clip position, and mains ?

wiredgeorge awnsered my carburation question in another thread, thanks.

themachine wrote:

... they are glowing red hot under mild acceleration when warm....

Question please to confirm ---

Are the metal casings of all four plugs glowing red hot where they screw into the head?

Reason for asking -- While some problems affect all cylinders (such as ignition timing or compression), other issues such as intake air leak, clogged jetting, or low float bowl fuel level, sometimes plague only one cylinder.

Could be excessive compression.
What are psi readings on compression test?

Should use strobe type timing light to assure ignition being spot-on, and also that the advancer unit is working.

If these carbs have rubber vacuum nipple caps, maybe they are leaking and allowing air intrusion.

Would also assure correct float bowl service fuel level. Hopefully, the quick easy clear plastic tube method may be used to check the levels.


Wishing you success!

themachine wrote:

wiredgeorge awnsered my carburation question in another thread, thanks.

what was the q and a ?