Spark plugs?

[askmrjesus]

Originally Posted by 101lifts2

Spark plug heat ranges have almost no effect on the actual combustion temperatures unless the plug causes preignition or incomplete combustion.

I think that's what I said. A plug that's too hot will cause pre-ignition, which will translate to higher engine temps.

Originally Posted by 101lifts2

You should use whatever plug is recommended for fuel injected engines.

My KTM disagrees.

You should use whatever plug is spec'd for your bike. I'm not aware of any "fuel injection only" spark plugs.

JC

[101lifts2]

Originally Posted by askmrjesus

Yes, but which way do you point them?

"Conventional Wisdom" dictates that you point the gap toward the intake (so the ground strap doesn't block the air/fuel mixture) but some engine configurations seem to work better with the gap facing the outlet valves.

JC

If the thread starting position in the head is the same then in theory the plugs will all be at the same position. It shouldn't matter which way the plug points if the air/fuel charge has swirled enough to make the mixture homogenous.

[askmrjesus]

Originally Posted by 101lifts2

If the thread starting position in the head is the same then in theory the plugs will all be at the same position. It shouldn't matter which way the plug points if the air/fuel charge has swirled enough to make the mixture homogenous.

Those are nice theories.

Unfortunately it doesn't work that way in the real world.

For one thing, even if the heads of mass produced bikes had all their threads in exactly the same sync (which they don't) the spark plugs would still not be. The ones I'm holding in my hand aren't, and they weren't exactly cheap, so, so much for theory #1.

As for theory #2, whether or not the fuel/air mix swirls perfectly, depends on many variables, including variables caused by after-market mods like air filters, so, so much for theory #2.

The question isn't whether or not the bike will run, it's, can you make it run better?

JC

[ZUKIMON]

NGK FTW. If that's not available and I have to have something right then.......ND will usually suffice.

As for Bosch, I have removed more of those plugs from car engines for causing misfires than any other plug. I have actually removed Bosch Platinum plus 4's that were only 30 miles old cause they were causing more issues than they were stopping. I don't like 'em and will never use them again. I also only like a Champion in a lawn mower or chainsaw.

[marko138]

I think I've got a Champion in my mower. Suckers gotta be 10 years old at least, runs like an animal.

[BobTheBiker]

Originally Posted by ZUKIMON

I also only like a Champion in a lawn mower or chainsaw.

MY chainsaw only likes NGK plugs. those champion pieces of shit just anger my old McCulloch 10-10 auto, as well as the Jonsered 670 I used to have, and all my previous Stihls. That said, NGK is king for plugs of quality.

[marko138]

Originally Posted by BobTheBiker

MY chainsaw only likes NGK plugs. those champion pieces of shit just anger my old McCulloch 10-10 auto, as well as the Jonsered 670 I used to have, and all my previous Stihls. That said, NGK is king for plugs of quality.

Gotta keep the saw happy. No one likes an angry chain saw. They bite.

[Yamerhaw]

well the old ones looked perfect, but since i had already went to the trouble of taking them out, i just put new ones in anyway, just went back with the NGK

[Yamerhaw]

Originally Posted by ZUKIMON

NGK FTW. If that's not available and I have to have something right then.......ND will usually suffice.

As for Bosch, I have removed more of those plugs from car engines for causing misfires than any other plug. I have actually removed Bosch Platinum plus 4's that were only 30 miles old cause they were causing more issues than they were stopping. I don't like 'em and will never use them again. I also only like a Champion in a lawn mower or chainsaw.

i agree about the Bosch, we've replaced SEVERAL at my work too

[tached1000rr]

Originally Posted by Yamerhaw

well the old ones looked perfect, but since i had already went to the trouble of taking them out, i just put new ones in anyway, just went back with the NGK

How many miles on your bike?