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Discussion Starter · #1 ·
Hello Hello. First post here because I can usually find what I need just by searching the forum.

Have a CL450 with a pamco ignition in it.

Just finished a top end tune up and I reinstalled everything (including new plugs) but I'm having the weirdest issue with my ignition.

The bike initially fired up but was not firing on the righthand cylinder. I rechecked my wiring, and still no fire on the right side. At that point I swapped my plugs, and the bike doesn't fire at all. I pulled each plug and grounded it on the outside of the motor, and both plugs show spark. But when I reinstall them, I don't think they are getting spark.

I say this because when I hooked up a timing light, and I hit the starter, no light on either side.

But when I pull the plugs, ground to motor, hit the starter, the timing light is lighting up.

I've triple checked all wiring of the pamco ignition, and I am absolutely stumped on this one. Any thoughts?
 

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Odd one alright.

It's not something simple like a directional spark pickup clamp being mounted the wrong way giving no reading during some of the tests?
 

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Do you have the original coils and plug caps? It takes more spark power to fire the plugs under pressure than when just exposed to the air. Also, you could just be twisting the plug wires or caps so that good contact is made when testing outside the head, and then contact is lost when the plugs are in. You could try removing the caps, trimming about 1/4" from the ends of the wires, and reattach the caps; assuming there's enough wire to trim, of course. Nothing you can do if the wires are losing contact at the coil ends, except replace the coils.
 

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Is there nothing else changing between when you see spark and when it doesn’t seem to with the plugs in?
Points cover on/off
Other covers on/off
Just wondering if just a cover pushing on something is effecting it.
I have left the plug in place and used a spare plug in the cap and grounded to check spark and keep the compression before


Sent from my iPhone using Tapatalk
 

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Not ODD at all.

It is common for PLUGS that are bad to SPARK outside of the cylinder but not when installed.

As said before it takes a lot of energy and a clean path for the spark to jump the gap under full compression.

More than once I've pulled & pulled & pulled on a Lawn Mower, Weed Whacker, etc., checked the Plug for Spark got a nice spark outside of the Cylinder.
Than changed the plug and had the device start right up.
Try the old Plug again and NOTHING.

A tiny crack in the insulator that you will never see with the naked eye won't matter when not under compression.
But add 170 +/- PSI of compression and the energy will find that crack as the shortest path to ground.

Spark PLUGS are too cheap not to give a new set a try.

Also don't discount the TRIM 1/4 to 1/2" off the Spark Plug Wires then screw the Caps back on.
I've seen where the end of the wire - where the cap screws on be just a DEEP HOLE.
The Spark Energy can and will erode the contact surface from jumping a gap between the Screw Contact and the inside of the wire.
Trimmed back connection, screwed into a clean section of wire can work wonders.
 

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Widen the plug gap and check for spark outside the motor. Open the gap to simulate compression. Never tried this on a plug test but have tested coils this way to simulate higher RPM.

Bill
 

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Im with Yendor...... sometimes the simple solution is your best friend. ALSO, new plugs arent always 'the fix"....Just ask my wife!!! Here is my story....
My Tri**ph, is a basket case, rough looking, leaking fluids, no shock fluid, dirty...but the motor is a one kick (YES-one kick!)start...when 'building" this bike I started with getting the motor and drive train solid before visuals and cosmetics..(carbs, coils, ignition)...and I would usually just take it for quick runs to the store... In doing this I discovered that the charging systems on these old bikes were crap at best and charge at higher RPMs... well my trips were short and through neighborhooods (25-30MPH). One day I went to take a ride to the store, kick..spit, bang, sputter...no start. Noticed the headlight was dim,(low battery), and after reading mountains of threads on "eletronic ignitions for vintage bikes" one thing I discovered (no matter the brand) they do not operate properly with low voltage...
Charger installed, bad weather, new set of NGK plugs arrive (gapped and installed).....Weather clears up, nice day, getting ready to take a trip to the grocery store. Helmet on, bike rolled out, tickle the carbs, ignition on (bright head light),...spit, fire, BACKFIRE, sputter...WTF!!!! This bike was running like a Swiss watch....Pulled the plugs, laid them on the head (grounded)..spark, spark, spark...Huh, maybe I flooded it..Few minutes later..same thing....
NOW...6-7 months pass TRYING to fix this problem ..New coil, plug wires, rewired the bike TWICE (possible bad ground)...and even put points back in...I was (and still new) to these motors, but I had holed a piston and rebuilt it myself and got it to great running status..until this!....For the life of me I couldnt figure it out...at one point I even checked the cam gears thinking a tooth broke and f-ed up the valve timing.
Well, its summer 100+ degrees out in the garage, Im STILL working on this POS, my wife comes out and sees my frustration is to the point that im gonna get rid of this bike. I explain, "I dont understand!?, this thing was running perfectly....no issues...then it wouldnt run (stay running) proper..." She asks, when? I tell her about the battery charging, ignition low voltage stuff ect....she then asks..."what did you do to it after you charged it?'' ...I say, "put a NEW set of plugs in it"....she replies..GET READY FOR IT.. "can new plugs go bad?"....my brain locked up and I literally stopped, and I said "but they are NEW".. I looked at her, waled over to a Maxwell House coffee can that has leftover parts from EVERYTHING I have ever worked on...pulled out 2 OLD, RUSTY, Champion plugs, grabbed some 40 grit sandpaper...knocked off the rust, blew them off, installed them.......
Guess what happened next!!! KICK...VAROOM!!! NO SH*T!!! The new NGKs ...well, from what I could guess, one was bad, grounding itself...but with my SINGLE COIL duel feed...it caused the plugs to fire at weird times....
My bike was down almost all summer, and I was chasing this gremlin for months...all because of BAD PLUGS.... and I couldnt get mad... my bike was now running again as it did before....and the best part is "My wife fixed my bike"....
 

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Not ODD at all.

It is common for PLUGS that are bad to SPARK outside of the cylinder but not when installed.

As said before it takes a lot of energy and a clean path for the spark to jump the gap under full compression.

More than once I've pulled & pulled & pulled on a Lawn Mower, Weed Whacker, etc., checked the Plug for Spark got a nice spark outside of the Cylinder.
Than changed the plug and had the device start right up.
Try the old Plug again and NOTHING.

A tiny crack in the insulator that you will never see with the naked eye won't matter when not under compression.
But add 170 +/- PSI of compression and the energy will find that crack as the shortest path to ground.

Spark PLUGS are too cheap not to give a new set a try.

Also don't discount the TRIM 1/4 to 1/2" off the Spark Plug Wires then screw the Caps back on.
I've seen where the end of the wire - where the cap screws on be just a DEEP HOLE.
The Spark Energy can and will erode the contact surface from jumping a gap between the Screw Contact and the inside of the wire.
Trimmed back connection, screwed into a clean section of wire can work wonders.
Wouldn't have thought the chances of two new plugs both being faulty were that high ?
Agreed a different set would soon let you know one way or the other though.
 

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YEP - It doesn't matter what the PLUGS do when they are NOT installed.

And - in the Case of SPARKS PLUGS - LOOKS DOES NOT MATTER. - Only Performance.

REALLY at Approx $3.00 per PLUG just spring for a new pair and try it.
 

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Discussion Starter · #11 ·
YEP - It doesn't matter what the PLUGS do when they are NOT installed.

And - in the Case of SPARKS PLUGS - LOOKS DOES NOT MATTER. - Only Performance.

REALLY at Approx $3.00 per PLUG just spring for a new pair and try it.

Well how about that. New plugs for the win. Those "old plugs" were essentially new so I didn't even think that could be the case.

Now I just have to deal with the fact that my right cylinder compression somehow dropped from 150 to 50...:eek:
 

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Do a leak-down test... that will tell you exactly where you r loosing compression
 
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