Veifying dead cylinders

Reply Subscribe

Thread Tools

Search this Thread

Dec 30, 2008 | 05:17 PM

Oldguard 7

Thread Starter

Melting Slicks

Joined: Apr 2002

Posts: 2,337

Likes: 14

From: Norfolk VA

Veifying dead cylinders

Outside of a compression test or a leak down test. Is it safe to remove a spark plug wire from the dizzy tower to "kill" a cylinder. I have a poor idle and am wondering if I'm running on all cylinders. I'm I correct to assume that the idle will change once a plug wire is removed from the dizzy tower and if the idle does not change, the cylinder is dead?

Last edited by Oldguard 7; Dec 30, 2008 at 06:01 PM.

Dec 30, 2008 | 05:27 PM

jakesindy

Melting Slicks

Joined: Jul 2008

Posts: 2,908

Likes: 3

Quote:

Originally Posted by Oldguard 7

Outside of a compression test or a leak down test. Is it safe to remove a spark plug wire from the dizzy tower to "kill" a cylinder. I have a poor idle and am wondering if I'm running on all cylinders. I'm I correct to assume assuming the idle will change once a plug wire is removed from the dizzy tower and if the idle does not change, the cylinder is dead?

You are correct

Dec 30, 2008 | 07:09 PM

mrvette

Team Owner

Joined: Jul 1999

Posts: 65,492

Likes: 230

From: Orange Park Florida

YES, you are correct, just like above....NOW here is the funny part.....

LONG long time ago in a land far far away, a old friend did just that....and the spark knocked him backwards into the bushes....

so what does he do?? get up and try it again.....same result....

I guess he was not used to being bit but good.....

true story......

Dec 30, 2008 | 07:27 PM

Dream Ride

Pro

Joined: Jul 2008

Posts: 660

Likes: 1

From: Springfield Tennessee

St. Jude Donor '09

Take a test light and ground the clip end. Take the pointed end and poke it into the top of the wire on the distributor cap. If it's not firing there wont be a draw down. If it is firing you'll see a big difference and not get knocked on your best intentions.

Dec 30, 2008 | 08:46 PM

Oldguard 7

Thread Starter

Melting Slicks

Joined: Apr 2002

Posts: 2,337

Likes: 14

From: Norfolk VA

Quote:

Originally Posted by mrvette

funny you mentioned that, I had my bones rattled by an HEI unit. It felt like the sensation when you hit your funny bone but the sensation is much longer than that.

Dec 30, 2008 | 09:14 PM

Tim_Ko

Racer

Joined: Jul 2006

Posts: 315

Likes: 0

I've got a 6 cylinder MC. Same problem; it runs badly ... why? How do you differentiate between running and non running cylinders. I ran the bike up to temperature, turned it off, got an infared thermometer and "shot" the exhaust pipes. It's immediately apparent which ones aren't firing. They have digital readouts and you don't have to move from wire to wire. I never tried it on a cast iron exhaust manifold but it should work on a header.

Dec 30, 2008 | 09:30 PM

...Roger...

Race Director

Joined: May 2006

Posts: 16,528

Likes: 53

From: Dayton, Ohio

If you have a infrared temp gun you can shoot the exhaust manifold.With headers it really works good but still works with the cast iron manifolds also just not quite as good.

edit -oops didnt see the above post.

Dec 30, 2008 | 09:33 PM

wills670

Burning Brakes

Joined: Aug 2004

Posts: 971

Likes: 7

From: roanoke va

Quote:

Originally Posted by Oldguard 7

it will work and you will see a change in idle if you pull one that is working.

Big tip: take a wire and attach it to the pliers and the other to a good ground and make sure it won't come off. If you do this the electric current will go to ground and not you.