Total Motorcycle Community Forums

Are you having any problems with performance compared to before? That's a sure sign that you are having troubles.

If you suspect it's not getting fuel then clean the carbs.

Sev wrote:That sounds dangerous to me for some reason.

Just don't ground yourself to the bike while holding it.
I have done it quite a lot, and have seen others do it. Nothing bad happened yet.

fireguzzi wrote:While the engine is running, get a pair of rubber gripped pliers and pull the plug wire off the plug.

Won't that hurt the coil? I've been told that the spark plug needs to be on and grounded when running or you could burn out the coil.

Maybe I should have also said not to do it for a long period of time.

I have never experienced any problems while doing it. Thats not to say it couldn't eventually hurt it, I'm sure it could. But with MY experiences it has not.
After all, others recommend turning the engine over with no spark plugs to blow out the cylinders and I have never heard of any harm being done to the coils then. (yes I know everything happens a lot faster when the engine is running as opposed to just cranking it)
Same thing with a compression test, no ground.

On that note.

WARNING: MY METHOD COULD DESTROY YOUR MOTORCYCLE OR YOUR LIFE
PROCEED AT YOUR OWN RISK!!!!!

caution: My methods are also known to cause cancer in the state of California.

But seriously, Just pop it off and see what happens then pop it back on. Just a matter of a few seconds.

fireguzzi wrote:Maybe I should have also said not to do it for a long period of time.

I have never experienced any problems while doing it. Thats not to say it couldn't eventually hurt it, I'm sure it could. But with MY experiences it has not.
After all, others recommend turning the engine over with no spark plugs to blow out the cylinders and I have never heard of any harm being done to the coils then. (yes I know everything happens a lot faster when the engine is running as opposed to just cranking it)
Same thing with a compression test, no ground.

On that note.

WARNING: MY METHOD COULD DESTROY YOUR MOTORCYCLE OR YOUR LIFE
PROCEED AT YOUR OWN RISK!!!!!

caution: My methods are also known to cause cancer in the state of California.

But seriously, Just pop it off and see what happens then pop it back on. Just a matter of a few seconds.

I always ground the plug to the engine when I do either of those... maybe it's an urban legend eh?

Me too, I ground them whenever I'm doing something that involves that sort of thing.

In a compression test you're told to either ground the plugs, or disable the ignition circuit prior to starting.

I wasn't told that.
But you guys know best.
I guess you can just continue to spit on the headers, or better yet get one of them fancy pants laser thermometers and measure the differences in the heat of each header.

If there is a problem with that cylinder do a compression and a leak down test of the suspect cylinder. check the plugs for fouling. If plugs look ok make sure the gap is correct on them.

Hope ya get her figured out. Keep us posted.

You guys are out thinking yourselves here....

The fastest, easiest way to find a cold hole is to run an I.R temp gun over each of the exhaust headers as the bike runs. They should all be fairly close to the same temp. If one is just slightly warmer than ambient temp, it's not firing. If it's warmer than that, but 150-200* cooler than the rest, it is firing intermittently. Do this with the engine warm, preferably after a bit of a ride. Fix problem on cold hole.

It is best to disable the ignition when spinning the engine with any of the plugs out. Either with the kill switch if the starter will still turn, or by grounding the lead (an alligator clip from the engine to the metal plug clamp inside the boot on the ignition lead). This is because the engine is still mixing fuel with air when you spin the engine, but now that explosive vapor is being pushed right out the plug hole. And spark from the lead could ignite it. It won't kill you, but it will cost you your eyebrows, some hair, and probably a pair of underwear.

I have heard various people say that you can fry a coil by not grounding it. They tend to be people...... well lets just say, people who's opinions don't mean much to me. Not the folks here, but at work.... salesmen, guys in dress clothes behind desks most of the time, apprentices ..... you get the idea....

I do know that proper procedure for finding a cold hole on a big engine with watercooled exhaust and no pyros, is to disconnect each coil until you find the one that doesn't affect running under some load. Those coils go for over $500, and each cylinder has it's own. They don't want to risk burning those up left-n-right, so I feel pretty confident that it's not worth worrying about the coil either way..... FWIW....

Thanks for the insight BuzZz, much appreciated.