lost a cylinder...help

jpowell · Posted: April 2, 2009, 5:54 pm Post subject: lost a cylinder...help

So, I lost a cylinder on the highway. It was a dog to get it to the exit, which LUCKILY was mine, and was able to coast to my drive way. Unfortunately that was the end of my luck, since my driveway is a long uphill.
Anyhow. after playing with it. I have compression. It's not good, but its the same on both sides. somethin like 80 lbs, but its a $7 test set from harbor freight. I have spark. I have a pmaco iggi with the dual coil. I have fuel.
I can get it to idle on the right cylinder, but the left pops a little here and there, and ever few seconds blows a huge pop out the pipe. I checked the timing, and it was quite advanced, so I fixed that, but no change. Though maybe I jumped a tooth on the timing chain, but it APPEARS ok.

The engine runs a bit lean at top ends, haven't got the jetting right yet, and knew I shouldn't have had it on the highway. Was almost home and decided to speed up a bit. Then pop. It was sudden though, like somethin broke. I though sure I holed a cylinder, but it apprears ok. I'm stumped...

penn71911 · Posted: April 2, 2009, 6:05 pm Post subject: Re: lost a cylinder...help

You said you have spark, did you pull the left plug and check it to see if it's fouled, did you actually CHECK the left side for spark, or are you just going off the fact that the right is firing? I had a similar situation, happened all of a sudden, like flipping a switch... ended up being the spark plug cap on my right cylinder, burnt the internal resistor, ohm'd it out and it read open, no continuity... hense the coil was firing but it wasn't getting to the plug.

jpowell · Posted: April 2, 2009, 6:10 pm Post subject: Re: lost a cylinder...help

I'll go check that right now. But I swapped plugs left to right, to prove not intermittent plug. I clamped the plug to ground to run the engine without the plug in without burning up my coil. It was firing pretty hot.

Actually now that I think of it, I swapped wires left to right, since its a single output coil it dont matter... no change. Just bad things coming from the left cylinder

penn71911 · Posted: April 2, 2009, 6:21 pm Post subject: Re: lost a cylinder...help

yikes... well you could always take a peek... pull the plug out and bump the motor over till the piston comes up... shine a flashlight down the hole and hope you don't find anything...

Check the carb, make sure the slide isn't stuck, it should move freely up and down, and if you push it up and cover the oblong hole at the top of the carb inlet with your thumb, the slide should fall nice and slow...

pamcopete · Posted: April 2, 2009, 6:29 pm Post subject: Re: lost a cylinder...help

jpowell

Check the PAMCO rotor and make sure one of the magnets hasn't come out. If one did, then one cylinder would be getting a spark during the exhaust stroke, but not during the compression stroke, due to the "wasted spark" scheme of the dual output coil. That would explain the pop from the left cylinder exhaust when the mixture fires during the exhaust stroke.

jpowell · Posted: April 2, 2009, 8:33 pm Post subject: Re: lost a cylinder...help

pete... that actually was exactly what happened... I was going to PM you bout that.

But I pushed the magnet back in, and its still back firing and running rough. those aren't polorized are they? I think I put it in the right way cause it was discolored on one end like the rest....

pamcopete · Posted: April 2, 2009, 9:09 pm Post subject: Re: lost a cylinder...help

jpowell

Yes, the magnets are polarized, so take it out and put it back the other way. PM me for a replacement.

I'm in the process of sending out kits that address that issue. Basically, it's a large washer that you attach to the rotor using the nut that holds the rotor in. The kit will be available free to anyone who has a PAMCO system.

Here it is installed:

jpowell · Posted: April 2, 2009, 9:38 pm Post subject: Re: lost a cylinder...help

pete, that looks like a fender washer maybe drilled to fit. If that solves the problem I'll save you the shipping and put one in. I love your product, but the magnets did fall out. BUT it was running hot. and things expand when warm. so... BUT i did push that magnet back in and it didn't seam to help. tomorrow I'll try n turn it around and see if it helps. Thanks for a great product, and thanks a million for supporting it. JP

Retiredgentleman · Posted: April 2, 2009, 9:44 pm Post subject: Re: lost a cylinder...help

Wow, that seems a little strange. I would think the forces would only be centrifugal, with no side forces on the magnets??

jpowell · Posted: April 2, 2009, 9:48 pm Post subject: Re: lost a cylinder...help

have you felt these old girls vibrate??

xsjohn · Posted: April 2, 2009, 9:58 pm Post subject: Re: lost a cylinder...help

Like granny's titties on a run away hay wagon at 8.7-1......... Laughing

xsjohn

jpowell · Posted: April 2, 2009, 10:03 pm Post subject: Re: lost a cylinder...help

I knew you'd pipe in john... just was hopin it wouldn't be you yellin at me for takin the old girl on the high way..

pamcopete · Posted: April 2, 2009, 10:10 pm Post subject: Re: lost a cylinder...help

jpowell

Well, that's basically what it is, but you have to use a low profile nut to provide clearance for the lock washer, or use a nut with a built in lock washer, as shown. So, other than verifying the problem, PM me your address and I'll send you a new rotor and kit.

pumps · Posted: April 2, 2009, 10:49 pm Post subject: Re: lost a cylinder...help

I'm envisioning a thin round clear (or not clear) piece of plexi to cover the magnets? On both sides?

jayel · Posted: April 2, 2009, 11:00 pm Post subject: Re: lost a cylinder...help

ferrous washer doesn't screw up the triggering? maybe ally washer or epoxy coating

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

I looked at the two photos -- so where the heck are the magnets? Anybody got a pic of the magnets correctly in place? Please post if you do.

jpowell · Posted: April 3, 2009, 7:32 am Post subject: Re: lost a cylinder...help

I like epoxy...

Buddy78SX650 · Posted: April 3, 2009, 7:41 am Post subject: Re: lost a cylinder...help

jimmythetrucker wrote:

I looked at the two photos -- so where the heck are the magnets? Anybody got a pic of the magnets correctly in place? Please post if you do.

The magnets are the four small circles on the rotor.

TeeCat · Posted: April 3, 2009, 8:35 am Post subject: Re: lost a cylinder...help

Pete, I have a kit on the way. How might we go about getting that fix for a preemptive strike?

TC

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

If the magnets are the four small circles, then I'm with jayel and jpowel. Epoxy is the thing there.

pamcopete · Posted: April 3, 2009, 10:52 am Post subject: Re: lost a cylinder...help

TeeCat

PM me your address.

MN_TX650 · Full Member Joined: Jul 17, 2008 Posts: 331

Ditto to what Tee Cat said! I bought a kit from Mikes and will be installing it this weekend...but would hold off for the washer fix if it is available...

pamcopete · Posted: April 3, 2009, 11:01 am Post subject: Re: lost a cylinder...help

MN_TX650

PM me your address. The kits are available.

yamaman · Posted: April 3, 2009, 11:14 am Post subject: Re: lost a cylinder...help

pumps wrote:

I'm envisioning a thin round clear (or not clear) piece of plexi to cover the magnets? On both sides?

I would guess that the magnets would only have a tendancy to throw themselves out, not in, due to centrifigal force?

If that was the case, blind holes in the rotor might be the go, if you can shorten the magnets that much?

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