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xs650 > > After Market Products > > Pamco - Electronic Ignitions > > Dead Cylinder Method


Dead Cylinder Method
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cpotts454
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Joined: Jun 21, 2007
Posts: 447
Location: Louisville, KY

PostPosted: April 6, 2009, 1:35 pm    Post subject: Dead Cylinder Method

Will using the dead cylinder method to carb tune with pamco's electronic ignition damage the internals of this ignition system?

Thanks.
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Retiredgentleman
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Joined: Mar 03, 2007
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Location: Calgary, Alberta 1978 XS650 SE

PostPosted: April 6, 2009, 1:44 pm    Post subject: Re: Dead Cylinder Method

You must keep both spark plug leads connected to a spark plug and the spark plugs must be grounded.

I use an alligator clip and short piece of wire to a plug to do my dead cylinder testing.
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pamcopete
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Joined: Oct 10, 2008
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Location: South Carolina

PostPosted: April 6, 2009, 2:02 pm    Post subject: Re: Dead Cylinder Method

cpotts454

If you have vacuum barbs, then you can just pull the vacuum line from each, one at a time. The resulting lean mixture will kill the cylinder.This method also allows you to do each cylinder withour shutting down the engine, and you can quickly switch from one to the other to verify the sync. On BS34's, the revs may go up when you pull the line off of the barb. Just wait a few seconds and it will settle down. I have also found that you will get best results if both mixture screws are set the same, because often the mixture screws are screwed up because people are adjusting them to compensate for an off sync condition.

After syncing in this manner, I then "fine tune" the balance by turning the sync screw one way or the other until both exhausts sound the same. No more than a 1/8 turn either way. Works best if you have real dual exhaust without a crossover.

Then, for a final touch, if you have vacuum barbs, connect the barbs together with a length of 3/16 vacuum hose. Use "T's" for the pet cocks, if you have vacuum petcocks. This final touch will smooth things out incredibly, and it prolongs the time between syncing.

When you first connect the barbs, the engine speed will increase, because each cylinder is getting twice as much mixture, so just turn the idle down.

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cpotts454
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Location: Louisville, KY

PostPosted: April 6, 2009, 10:28 pm    Post subject: Re: Dead Cylinder Method

So pete I assume by this you do not recommend the dead cylinder method via pulling the plug with your system? Just want to be sure. Wink
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pamcopete
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PostPosted: April 13, 2009, 5:11 pm    Post subject: Re: Dead Cylinder Method

cpotts454

Well, it's not just my system, but any system that uses a dual output coil. A dual ouput coil does not have any internal return via the primary terminals, so if only one plug is connected, the high voltage will find a way to ground by arcing through the insulation of the coil to the primary terminals, thus ruining the coil, not the electronics.

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cpotts454
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PostPosted: April 13, 2009, 11:14 pm    Post subject: Re: Dead Cylinder Method

Oh, ok pete... I understand now. Thanks for the explanation.
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