Coil Problems?! Testing Ohms and Volts..

18576 Views 47 Replies 3 Participants Last post by CAM2, Oct 10, 2012

N!pples

Discussion Starter · Sep 24, 2012 (Edited)

I took the Blata 13 to the race this weekend also. It was running great. Then on race day I couldn’t get it started.. I had spark so I checked compression.. 80 PSI.. DOH! After another racer with a blata bike died and he seemed to be having the same issue we checked his PSI with my Compression tester.. 80 PSI.. Then a scooter racer wanted to check his PSI.. 65! Lol Was my compression tester broke? The scooter was starting and hauling as.s on the track?! I checked my BMS and it was showing 120 when it was showing 170 before I left for the races.. I didn’t know what to think. Maybe it broke maybe its not.. lol

So I just took my time and checked the reeds, cleaned the carb and put it back together.. Low and behold it started! Shot a bunch of gas out the muffler then sounded strong.. I took it for a spin and it started out great then kept missing a beat.. It died but I was able to start it again.. Charged it back to the pit and it was still idling but skipping for sure.. I changed to a 1 size cooler spark plug and it ran a little better but still skipping or bogging just a little.. The scooter racer said he thinks its my coil or ignition something.. When that thing bogs at high speeds its scary.. It has no stabilizer.. It took a little bit to get it started today but I did get her to start and it almost sounds fine on the rack..

I can’t seem to find a clear answer on what the correct Ohms should be and what setting should I read it at? 2000k ya?
The Coil Ohms test shows 5.86 at 200k and 10.80 at 2000k Positive to Cap and Negative to mount hole
The Ohms reading on my BMS are a little lower at the 2000K in the 8.somethings.. But the Same on the Polini 10.8 and 5.8 something.
Cam, U posted in an Old thread..

“On the flywheel is a set of magnets set side by side;-this is called a "magneto"........... they should be clean and free of rust;-so should the pick-up coil............the magnets revolve past the pickup coil;-this passing produces a magnetic pulse..........this magnetic pulse is transmitted to a/c power to power the plug through the coil windings...............theres a certain size air gap between the pick-up and the magnets in their passing to produce the strongest spark;-that gap is the thickness of a business card........................

you can test the coils power output with a digital multimeter................

remove the sparkplug to get the best revolutions for the test....................

set the multimeter to 500 or 750 volts a/c....................

stick the red probe in the sparkplug boot......................

ground the black probe to the engine good........................

pull the pullcord and note the voltage reading while the engine is rotating....................

it should read around 448 volts a/c.................if you dont get voltage thats 448-425 volts a/c;-the coil is bad and needs replacing..............Peace”

I tested the coils on all my Euro bikes and it seems to be all over the place when I pull but when it stops the Voltmeter reads 538 or close on all 3 Bikes. I’m assuming this still good?!

****! I just went down to double check my numbers and is seems my volt meter has malfunctioned.. Its sparking on the display when I pull my cord and leaving perminate marks.. It constantly reads 536 or -1 on all settings.. Oh ****! Not my day, Again! lol

Even my tools are breaking! On a good note! The BMS Rocked it!! That bike is very nice!!

Thanks in advance Cam and EPR..

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