Spark plugs keep closing gap.

[cxbra]

Why do my spark plugs keep gapping down after a few hours? I always gap to .030 and when my bikes starts acting funny, I pull the plug off and sure enough its at .020-.025. Maybe when im gapping, im gapping the arm part instead of the electrode, causing it to keep warping.. Anybody have any clues? Is it just the way it is?

 

[minidragbike]

Maybe the piston is slightly touching the spark plug? If so add a index washer, and try it again. Also I normally run from 0.035"-0.042" depending on plug, flywheel, and fuel I'm running.

 

[Cyanide]

ive used a sparks plug that was too long and when it started it would die from the plug gap being closed from my valve hitting it. (flathead briggs)

 

[cxbra]

ive used a sparks plug that was too long and when it started it would die from the plug gap being closed from my valve hitting it. (flathead briggs)

But, the thing is it only happens after about 3-5 hours of riding. It almost seems like im not gapping them correctly and they warp from the heat. Im going to start over w/ a new plug and gap it progressively with a spark plug gapper instead of stretching the gap open. I think that's the problem.. Thanks guys.

 

[balljoint]

either engine is overheating or or you have carbon build-up on top of piston crown:bowdown:

 

[J72]

Gap to .050" and see what happens.

 

[mmisterbungl]

try just running it without the spark plug. start it up , then take it out real quick and keep the throttle pegged while you're doing it.

 

[ogygopsis]

try just running it without the spark plug. Start it up , then take it out real quick and keep the throttle pegged while you're doing it.

what????

 

[balljoint]

try just running it without the spark plug. start it up , then take it out real quick and keep the throttle pegged while you're doing it.

ut:ut:ut:ut:ut:ut:ut:ut:ut:ut:ut:I think he is serious,:blink::blink::blink::blink::blink::blink:

 

[Leftythenub]

i hope not... :scared:

 

[mmisterbungl]

Just :censure: around fellas

 

[cxbra]

either engine is overheating or or you have carbon build-up on top of piston crown:bowdown:

Carbon buildup, thats it! I always wondered why my plug would carbon up after every-other ride! It was burning a lot of oil before I switched from 10w to 20w and I think that caused a lot of buildup. Is there somethin I can do in the form of fuel additives, I really dont feel like cracking this engine open until I get a billet rod (if it aint broke, dont break it!). Actually i'd only have to take the head cap off right?

 

[george3]

flat head engine just pull the head and clean it up. 10w? where do you live in the north pole. lol

 

[balljoint]

Carbon buildup, thats it! I always wondered why my plug would carbon up after every-other ride! It was burning a lot of oil before I switched from 10w to 20w and I think that caused a lot of buildup. Is there somethin I can do in the form of fuel additives, I really dont feel like cracking this engine open until I get a billet rod (if it aint broke, dont break it!). Actually i'd only have to take the head cap off right?

bg-44k or a top end cleaner,remove spark plug and make sure piston is down,pour in cleaner and let sit over night,may be a bear to start and oil may need to be changed if it gets in the crankcase ,depends on how well your rings are sealed.:blink::blink:

 

[J72]

Why couldnt you just roll the engine over to around TDC and clear the carbon in the electrod area through the plug hole? Or just stick a washer under the plug like previously mentioned. I remember hearing a couple times that you could spray a fine mist of water into the carbs inlet while the engine is up to temp and running to clean carbon. Ive never tried it, It seems that a chunk of smeg getting caught on a valve seat would not be worth the conveinence.

 

[DZLBIKE]

Try Seafoam first.

Sea Foam | How to Use Our Products

Will fog up the neighborhood, but will clean the gizzards out of the innards.

 

[cxbra]

I think im going to pull the head off and check out the piston top and clean it off. I've heard nothing but good on seafoam, I think im going to try that on payday. Thanks fellas.