B4 Coils

[aNiMaL]

Hi all,

I have just been reading loads of old posts about testing coils and there readings.
When to reply to one of them but it told me to start a new thread as the other one was too old.....

I been having running probs , bikes been in bits in me garden for the last 5 weeks now,
Had the carbs off god knows how many times .
Desided to quadrupal check the sparks on #1 again, and noticed it was very very weak to non existant.

checked the manual for the readings then set about testing.

To be honist im not sure of the results as the settings and my multimeter are differnt.
I'm suposed to use 1 ohm and 1K ohm settings and my meter dont have them.



For the + & - spades , i used the 200 ohm setting and got 03.7 ( on the 2000 ohm setting it jumps between 003 & 004 ) .
For the spark plug caps ,I used the 200K ohm setting and got 39.2 ( on 20K ohm it just flickers or stays at 1, & on 20M it give 0.04 ) .
These numbers seam to be on par with the manual, but the testing ohms are way off so the results are completly wrong  ???? .
Also ,b4 i took the coil off the bike, i poked the test lead ends in the spade connector blocks ( red to + & Black to - ), and fired it up,  I only got a reading of about 5v ( on the 20v meter setting ) , going to double check this in a min when i put it back on.
Is this how U check the voltage supplied from the CDI to the coils, or am i suposed to do red to + and black lead to earth/ground ?

cheers , Jay

[Chris H]

The actual setting on the test meter is not important so long as you start higher than the manual, so if the manual says 1k and you set at 2K you will get the same reading. If you notice as you flick the meter setting the point just moves up or down until you get a too high/low reading and the meter shows 1.
You need to remember that the coil feeds 1 and 4 so if 4 if firing then the supply must be good so swop 1 and 4 to see if the fault swops to 4. If it stays at 1 the fault must be the plug or carb if the spark is nice and blue (not yellow).
To check voltage supply you would put your + probe on the + supply at the coil and the - probe to ground.
Hope this is of some help.
Chris.

[aNiMaL]

Thanks Chris.

The reason i was checking coils, is, #1 plug/ lead, was not giving a nice bright blue spark.
It looked rather frail and week to be honist . New plug in lead, with not so old one still screwed in barrel  , just to test ....


I did type this bit below about 5 min after the first post, but went back out to test coil for #2 & #3.
Just came back in , copied what i had wrote and refreshed the page just incase anyone had answered already.

...............
ok , update . ( from earlyer , about 2:35pm )

just started the bike up with #2 & #3 coil connected ,
& #1 & #4 coil back on the bike and plugged up , but disconnected from the 2 spaded wires.
I put me red and black tester leads on the spade connectersand got these results.
Bike started with a cold engine & about 3/4 choke , within sec's .
and ticked over ( only firing on #2 & #3 )
Gave it a little gas and the revs and Voltage climbed slowly to about 6v-ish.
A little more revs and it went up to about 8.5v (ish).

This is taking reading from the 2 wires ( + orange w/white & - white ) that connect to the spades on the coil ..

Is this normal ??
.............................

BACK to now ,

I now see i should of used an earth for the black lead so above is probably way off.

Also, i was faffin about and didn't / couldn't get propper readings of the 2nd coil , the way i did the 1st one.
( left it all connected and tried to just poke and prod at it with the test leads, but it needs a clean up like i did to coil 1. )

ive just put it all back together for now, ( first time tanks been on in 5 weeks ).
started it up , first click, its still warm from earlier.
Still not got 'fizzzal' on down pipe #1, even though it sits ticking over at about 1 1/2 , and reved up to 10k on a quick plip of the throttle .

I just dont get it . lol

Cheers again . Jay

[Chris H]

Ive done this myself and i know from experience that if 4 fires 1 should unless you have a bad ht lead, cap or plug. You can swop them over and if thers a fault it will go over to 4 if not it is 100% the pilot system and 99% of the time if you take the pilot jet out it will have a micro piece of dirt in it. The pilot jet is only .32 or something similar and this is VERY small and can pick up crap from the float bowl real easy.

[canyonbreeze]

Your resistance readings look fine.  As far as the signal going in you need an oscilloscope to really check it.

If #4 fires and #1 doesn't your problem is most likely the high voltage wire, the cap on the plug or the spark plug itself.  Try separating the cap and seeing if there is corrosion on the plug cable.

Or get rid of plug cable problems forever by switching to coil on plug.  That is discussed in another thread.