Bike loses power

[naustin]

I had a similar problem once upon a time.  Changed the coil, ignition modules, plugs, and spent months chasing the problem.  

Turned out the 6 year old OEM plug wire was bad creating an intermittent fault.  The carbon core wire degraded from heat and vibration.  Do yourself a favor and spend $20 to replace the wires before you do the coil...

[dm_gsxr]

Yes this is possible, but you might have noticed a bit of a rough running condition with half of the spark gone even if each cylinder had one good coil. Ever ride a BMW with bad stick coils?  Runs like crap when put under a load but not too bad at idle.

Get one of these and do a dynamic test of the coils

http://www.amazon.com/Thexton-404-Adjustable-Ignition-Tester/dp/B0002STSBM

Easy to use and cheap.

Can you explain what it does? The description is rather simplistic and I'm curious what this is looking for.

Thanks.

Carl

[dm_gsxr]

I had a similar problem once upon a time.  Changed the coil, ignition modules, plugs, and spent months chasing the problem.  

Turned out the 6 year old OEM plug wire was bad creating an intermittent fault.  The carbon core wire degraded from heat and vibration.  Do yourself a favor and spend $20 to replace the wires before you do the coil...

The plug wires look brand new. And the tests are either with the cap (which I did) and without (which I didn't do). It sounds like I should check it both with and without although with the caps did pass the resistance test.

Carl

[naustin]

Mine looked good too.  And, the bike would rune fine for weeks, then suddenly leave me stranded.  (single)   Due to the intermittent nature of the problem, I never suspected the plug wire.   It was the last item I replaced - as an after thought - but it was the problem all along.  I never did test the resistance of the wire - so not sure if that would have indicated a problem or not...  Might have depended if the wire was tested laying flat, or with a bend in it...

[Andrew]

Can you explain what it does? The description is rather simplistic and I'm curious what this is looking for.

Thanks.

Carl

Well in a nut shell, you can adjust the gap that the spark has to jump. THe wider you make the gap the more you force the coil to put out IE: Stress Test the coil.  

If you think you have a bad coil that is breaking down under load (unable to put out enough power to light off the plug) Just unplug the wire from the plug and plug in the adjustable spark tester. THe tester is marked to show approximately what current it will take to jump the gap.THe larger the gasp you have set the higher the voltage it takes to jump it. Most bike coils will put out at least 30k Volts (well enough to jump the plug under load)  Well with this cheap tool you can see what you coil is capable of doing.
Cheap and easy and no chance of getting zapped

[dm_gsxr]

Well in a nut shell, you can adjust the gap that the spark has to jump. THe wider you make the gap the more you force the coil to put out IE: Stress Test the coil.  

If you think you have a bad coil that is breaking down under load (unable to put out enough power to light off the plug) Just unplug the wire from the plug and plug in the adjustable spark tester. THe tester is marked to show approximately what current it will take to jump the gap.THe larger the gasp you have set the higher the voltage it takes to jump it. Most bike coils will put out at least 30k Volts (well enough to jump the plug under load)  Well with this cheap tool you can see what you coil is capable of doing.
Cheap and easy and no chance of getting zapped

Ah, thanks for the explanation. It makes sense   And per the reviews, you can get zapped from this thing

Carl

[black hills]

try opening the gas cap. If it fixes it you have a plugged vent tube (a tank bag will also cause this issue).

[dm_gsxr]

try opening the gas cap. If it fixes it you have a plugged vent tube (a tank bag will also cause this issue).

Actually what seemed to fix it the last two times was pulling off the left rear sparkplug cable. I just reached down and pulled it off and zip, I was off. I put it back on and it was ok for a few blocks. Pulling it off fixed it again.

That's one of the reasons for asking the other question above. If there are four spark plugs for two cylinders, would it still run, although with lower power?  Since three of the coils (the three I can check) all seem to be out of spec, I'm wondering if it's been low for a while and with the second of one cylinder bailing, the bike is only running on one sparkplug/cylinder.

I'll be pulling more bits off of the bike Saturday to get to the fourth coil. If it specs the same (.4 when the range is supposed to be .1 - .2), then it's either something else or just that all four need to be replaced.

I don't have a problem replacing them. I just want to make sure that's what the actual problem is

Carl

[Andrew]

Ah, thanks for the explanation. It makes sense   And per the reviews, you can get zapped from this thing

Carl

I give, you can get zapped if you put your hands on it while the coil is firing the plugs. (not a good idea to most folks) But can be rather enlightening experience

[naustin]

Actually what seemed to fix it the last two times was pulling off the left rear sparkplug cable. I just reached down and pulled it off and zip, I was off. I put it back on and it was ok for a few blocks. Pulling it off fixed it

I don't know it your coils are sketchy, but based one the above- I still think you need to swap the wires.  They are a lot cheaper than 4 new coils

[dm_gsxr]

It's certainly a cheaper first option, especially since it'll take longer to get replacements.

Thanks

Carl

[rgbeard]

In my experience, testing resistance on coils doesn't do well to identify a "sketchy" one.  It really only clearly identifies failed ones.

Sketchy coils are common on many of the Triumphs and exhibit a variety of interesting symptoms.

Some models of the Goldwings have a "Pulse Generator" to time ignition pulses that's a nasty bit to track when it's failed.  Fortunately (??) their failure is common enough that GW owners know to look there first.  

[andras]

Actually what seemed to fix it the last two times was pulling off the left rear sparkplug cable. I just reached down and pulled it off and zip, I was off. I put it back on and it was ok for a few blocks. Pulling it off fixed it again.

It might be possible to isolate the cause by swapping components around.  Swap spark plug cables,
does the problem move with the cable?  (that is, does unplugging the same location still fix it?  Or
does unplugging the old cable at the new location?)  Swap coils, does the problem move with the coil?
You've already replaced the spark plugs, no point in swapping those, but would have worked there too.

[TuffguyF4i]

Have you put a voltmeter across the battery to make sure you are getting the right voltage from the RR?  

Whenever i have a problem with my hondas, i look to the RR and battery before anything else.  

A bad RR would give you all the problems you have experienced.