Check your plugs! ...then replace them anyway!

[isaac]

So after doing my first ever carb removal and rebuild (about which I'm insanely proud of myself), I had irony slap me in the face today.

My plugs (autolite 4163s) in the 750 had been perfectly fine, never fouled, no weird wear, always showing blue spark in testing to the end. Gaps were all normal. I had even cleaned them with sandpaper to be sure they were clean. Still very difficult starting - which led me to going nuts with the carbs.

Anyway, I replaced the plugs today and the damn thing lit up instantly, and has done so ever since. Well son of a!

Moral: If your bike very suddenly has a hard starting problem, but runs fine in all other conditions, check your plugs, then replace them anyway.

[1100ED]

i used to replace my plugs every 100 miles and i was running a magneto--((SPORTSTER) .49 CENTS EACH ON A 2 CYLENDER ENGINE WASN'T TOO BAD THEN.
I still replace my plugs ever 1000 miles max.

[isaac]

Is there a recommended plug change interval for bikes? With my turbo Volvo it seems like I'm changing them out every 5,000 miles or so, which seems pretty excessive, but maybe for bikes its even worse.

Oh yeah, one more thing about the symptoms before the plug change. The only plug that was wet when I removed it was #2 - the only cylinder that was firing. All the others came out dry - as in they were burning the fuel.

[1100ED]

when #2 cylinder is wet and a misfire situation is evident, there may be a petcock leak if you have a vacume petcock.

[Jethro]

isaac Posted: Wed Mar 23, 2005 2:00 pm Post subject:

--------------------------------------------------------------------------------

Is there a recommended plug change interval for bikes?

I change em every 1000, but I'm too lazy to check the manual. It's all the way downstairs!

Saw a lot of bikes on the road today. Gonna snow tonight big in New England (so they say). I'm sick of the snowmobile and I've got and itch for cooties.

[SqDancerLynn1]

I ran the last set in my 79GS850 for about 9k miles & they still looked fine

[DMPLATT]

I changed mine in the beginning of december. I now have about 4500 miles.
Just looked at the manual and it says 4000.

Guess I'll be getting some plugs.

[crag antler]

I've got an itch for cooties.

Gotta be careful with that itch there Jethro, the only known cure is down South with miss 1100ed 8O

[Poot]

I've had my plugs on for about 18000km (just over 9k miles) on mine... They weren't looking too good. Now I know why.


Although, my 2nd cylinders plug did seem to be a little worse than the others.... what would this signify??




poot

[Anonymous]

The gunk in your carbs wasn't good and they needed to be cleaned anyway. I always keep a spare set of plugs in the toolbox. When I use them I get another set right away. It's saved my butt more than once.

[earlfor]

I would say that after 9,000 miles on a set of plugs, one looking a "little" bit worse than the other signifies nothing that you should be concerned about. :-) You're a fuzz rich on that cylinder, or you're burning a wee fuzz of oil. Either way, with that milage, it isnt broke, it isnt going to hurt a thing, if it runs nice, dont fix it. :-)

Earl

I've had my plugs on for about 18000km (just over 9k miles) on mine... They weren't looking too good. Now I know why.


Although, my 2nd cylinders plug did seem to be a little worse than the others.... what would this signify??




poot

[Dave W]

I've had the spark plug problem in the past myself on other small engines. Things like chain saws, lawn mowers, etc. are really picky about the plugs.

I always change the plugs in the GS850 at the start of the season. I go anywhere between 2000 and 8000 miles per year depending on my calendar demands. I never travel without a spare set.

[chuckycheese]

a long time

I think if you're running a well-tuned, 4 cycle engine with electronic ignition......they'll last a long, long time. 8)

[isaac]

So what plugs do you guys use anyway? Maybe Autolite 4163s aren't good ones for the bike. I've always liked NGKs for resisting fouling.

[SqDancerLynn1]

So what plugs do you guys use anyway? Maybe Autolite 4163s aren't good ones for the bike. I've always liked NGKs for resisting fouling.

Nothing but NGK Would the autolite be gapped correctly ??