650R ignition testing...

7 replies to this topic
  • motopsycho650

Posted September 18, 2007 - 03:47 AM


I'm reading in the book about how to test ignition parts in the big red pig. It says I need a "Peak Voltage Adapter" to plug into my multi-tester. Of coarse the book throws a Honda part number at you, (which are always over-priced, POS tools).

Are "Peak Voltage Adapters" commonly available? and where? I have a friend who is an electrition, and an uncle who has been in electronics repair for a long time, and neither of them have heard of a peak voltage adapter.

  • InternalCombustion

Posted September 18, 2007 - 05:07 AM


Good luck, motopsycho.

A couple of years ago I thought I had an ignition problem on my 650R (turned out to be sticking float valve on a brand new Edlebrock).

I read the same thing you did about the Peak Voltage thingie. Searched the web for 2 solid days, no luck. Could not find any freaking reference anywhere on the web for such a thing. I called the dea"er and their price for that device was like $180 as I recall. (???!!!). For what its worth, some higher-end multimeters have the ability to trap and measure peak voltage, mine doesn't.

My best advice (at least in my case), I just ran the other tests that are listed that do not require that device. All my ignition components seemed fine, and as it turned out were fine. Most TT guys will tell you that the 650R electrics rarely fail. I cannot remember reading any post here that said they had a verifiable ignition failure, except I think one guy did have a pulse generator that overheated and failed.

What symptoms lead you to believe you have an ignition problem?

  • HawkGT

Posted September 18, 2007 - 07:19 AM


I had a friend help me diagnose a no-spark problem on a bike way back when. He worked in the electronics field (Motorola). I seem to remember him saying that he was using an analogue meter (ya know, like with a needle that sweeps across a gauge) because they can react fast enough to read peak numbers. I think that was the reason anyway--this was a while back.

I do know he specifically did NOT use his normal whiz-bang digital multimeter. He used an analogue meter for a specific purpose and I'm pretty sure it was related to registering peak values.

  • martinfan30

Posted September 18, 2007 - 08:08 AM


in the automotive field, i much prefer a simple analog meter compared to my fancy FLUKE DMM. they just arent quick enough.

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  • AtomicGeo

Posted September 18, 2007 - 09:56 AM


The analog meter will also not be fast enough...although quicker response to transient voltages than a digital meter. The absolute best way to measure the voltage is to use a high voltage oscilloscope probe and to record and view it on the scope itself. A decent o-scope however runs about a kilobuck like from Tetronix, Inc. I am guessing that the peak voltage adaptor is some type of sampling circuit that then "hold" the peak voltage that is then read by a a digital or analog meter. The analog meter will probably give you a low side estimate of the peak voltage transient.


  • motopsycho650

Posted September 18, 2007 - 10:52 AM


What symptoms lead you to believe you have an ignition problem?

I am having major idling/low-end problems. When The bike is cold, it barely starts and will not idle on it's own. The exhaust & spark plug indicate a rich pilot. If I hold the throttle open about 10%, all cleans up and seems fine.

Once the bike warms up a bit, the idle gets quicker & quicker. If I give it gas, the idle will not come down.

This problem started about a month ago. I initially thought I had some gas with a bit of water in it. Prior to this, the bike ran great and was jetted almost perfectly (stock carb).

My logic said, and still says it's a carb problem. But I've had the carb apart 3 times now for cleaning. The last time, I soaked the carb in carb cleaner for around 12 hours. Nothing has improved the problem, or even changed it. Finally, I decided to follow the steps in the book for a low-end/idling problem. Low & behold, the first of those steps is to test the ignition.

A few other weird symptoms I have are:
1. I have a cutout air filter cover, and a twin air power-flow kit. I was always able to hear the air being sucked in, but since this problem started, the sound became louder and more noticeable.
2. The weekend this problem started, I was stuck on a nasty hill climb. With the bike shut off, gas started dripping out from the clamped boot between the carb & air-box.

Would it be possible I have a problem with the float? I know it's not stuck, and was adjusted correctly before this issue started. Could I have a bad float needle? I'm not sure if there's a spring inside the float needle, but mine seemed to be pretty soft. It's the only other carb thing I can think of...


Posted September 18, 2007 - 11:02 AM


I'm far from an electrical guru, but I also noticed something strange. My bike runs fine and runs the lights fine, but when I put a meter on the lighting leads, it shows around 13 volts or so at idle and then goes down as the bike is reved up. That is the wiring upstream from the regulator. Again, no issues with the lights, but seems like that would be the opposite of what you'd expect.

  • suharianu

Posted September 19, 2007 - 09:19 AM


take the fluke reading which is rms and multiply by 1.4 this the peak voltage

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