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WEAK ORANGE SPARK 2003 vn800

8K views 20 replies 3 participants last post by  magneto69 
#1 · (Edited)
got my 2003 vn800 15k on the clock V&H cruizers standard air box and filter 135 main /48 pilot jet A/F mix 4 turns out running rich coughing and sneezing

opened her up with 170 main and 52 pilot ran great sounded awesome while idling and still sneezing did top slide carby mod throttle smoother but still coughs and sneezes when riding checked plugs still very rich and wet not fuel fouled plugs

went to 140 main and 48 pilot jets and 1 3/4 turns out plus extra 1/2 turn on the A/F mix as per Russian wolf and a .018 brass washer shim on standard needle

took her for a spin on the highway blow out the cobwebs and get a spark plug reading 80 - 100km zones sweet great power and response all through the range gagged along the way gave it a flip of the throttle and she was good then again down the road she stalled I stopped and she restarted the 30 minuted into my ride she stalled and stopped I let her cool for a few minutes and she started not more than 500m down the road she stalled and was not able to restart weak battery

friend came and we replaced with fully charged battery swapped fouled plug in the rear with the clean plug from the front drained high octane fuel and replaced with 91 octane fuel checked spark against bolt weak orange spark on both plugs reconnected plugs and she kicked over rode home cautiously no heavy throttle she rode home through 60, 80 and 100k zones sweet and smooth no missing and stalling

got home checked plugs front fouled plug now much cleaner with grey tip and charcoal ring and clean porcelain the rear plug now looked the same

checked ignition coils front and rear primary readings 2.9 ohms - secondary readings front w/o lead 13.62 ohms - with lead 18.49 - front plug lead only no reading
rear coil w/o lead 14.04 ohms - with lead 18.86 ohms - plug lead only 4.83 ohms

front plug lead not showing reading tried rear plug lead on front coil 18.49 ohms - plug lead defective will swap

main reading on ignition coils firm just reading after decimal point flutters on both coils

tried applying heat with heat gun to ignition coils readings went from 13.79 - 14/15.00 ohms fluttering up and down

checked pick up coil through connector .4 0hms ( is this 400 ohms? or is it stator coil resistance which should be between .3-.5 ohms) (standard reading for pick up coil should be 380 ~ 570 ohms) i am testing through connectors at the end of the pick up coil added heat to pick up with heat gun and reading jumped up to .5 ohms

checked rectifier reads 872 one way and zero the other way on multi meter - all good

want to check ic igniter but paranoid as manual says not to use any other multi meter other than kawasaki one might damage unit

put new spark plug in leads checked for spark still weak and orange

battery fully charged - 12.59 v ( should be 12.6 or more)

coils are $230 dollars a piece from japan w/o plug leads

prior to taking her on the highway I rode around the neighborhood - again great while idling but after riding for a while 15 minutes started to feel like she was dragging and needed to keep revs up so she would not gag and stall and just got home - so i thought may be because i have just been starting and idling the bike that she needed a clean out so i thought i would hit the highway

mechanic said check earth wire connections found wiring diagram can see earth connections to battery, coils, fan, starter etc but no earth connection to frame of bike ?


any help would be appreciated
 
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#2 · (Edited)
I've had my motor out a couple times and the main ground goes from battery to the rear of the motor at bottom of the rear jug, in center of motor where cases bolt together. Make sure this is clean and tight. Another thing to check I've found o cars back in the day, if the power leads are reversed on the coil, you will get a weak spark from the coils. I have found my rear plug wire was corroded at the coil end causing an intermitting miss on the rear cylinder. Cutting about a 1/4-1/2" off the wire fixed this.
 
#3 ·
HI Rick

Thanks for the reply - do I need to take the motor out to access the ground wire?

will check the power leads are on properly I did not think the ignition coil would work if wrong wires were attached?

will look at rear plug wire - is showing a reading of 4.8 ohms resistance on multi meter should this read 0 ohms resistance in plug lead if in good condition - no corrosion present in either lead, front plug wire is frayed and is showing 0 resistance- and it is the rear spark plug that is being fouled with carbon build up - combustion is not happening - need to understand this before I go chopping leads

i am getting the feeling that the rear plug lead has resistance and is causing my rear plug fouling

and that the weak spark in both ignition coils may be a grounding issue
 
#6 ·
Thanks for the picture Rick - I had corrosion in there she's all clean and tight now.

sfair: I double checked my ignition coils as per service manual - secondary winding should be between 12.0 - 18.0 k ohms without the spark plug leads - checked them at motorcycle shop with mechanic and my coils are sitting at front 13.93 and rear 14.08 k ohms - all good

cleaned all leads, connectors and earth lead at motor, new spark plug cables kept the caps all good I have no resistance now, battery on trickle charge for 4 days - went to kick over bike to check for spark with new plugs and very weak orange spark still and bike hardly kicking over - I now have a clean electrical system and I suspect the battery does not hold a good charge and will need to be replaced - service manual states battery should be 12.6 v or more my battery will only charge to 12.59 and currently holding at 12.5 v

thanks for your help guy's I really appreciate it
 
#8 ·
Thanks for the picture Rick - I had corrosion in there she's all clean and tight now.

sfair: I double checked my ignition coils as per service manual - secondary winding should be between 12.0 - 18.0 k ohms without the spark plug leads - checked them at motorcycle shop with mechanic and my coils are sitting at front 13.93 and rear 14.08 k ohms - all good
The "k" makes all the difference in the world doesn't it?
 
#9 ·
just a thought guy's i might re check my pick up coil

service manual states

set multimeter at the x100 ohms range and connect it between the terminals in the connector

if the resistance is more than the specified value - the coil has an open lead and must be replaced
if the resistance is much less - the coil is shorted and must be replaced

pick up coil resistance: standard = 380 ~ 570 ohms

multimeter set at 200 ohms = .4 ohms (less .1 ohms for test probes added resistance makes my reading .3 ohms total)
multimeter set at 2000 ohms = 000 ohms
multimeter set at 20k, 200k, 20m = 000 ohms with decimal placings accordingly

multimeter set at highest resistance range - 20m ohms test between pick up coil leads & chassis ground
any tester reading less than infinity indicates a short necessitating replacement of the pick up coil assembly


my multimeter has no beeping option and the reading was = 0.L

If the screen displays a value of zero (or near zero), and the multimeter beeps. Continuity!
If the test current isn't detected, it means there's no continuity. The screen will display 1 or OL (open loop).


new to using multimeter but I feel i'm doing everything by the book

new spark plug leads - all good
know how to test rectifier now - all shows good readings
replaced battery that was not holding charge

resulting in stronger whiter spark but still bit of orange in there

took bike for a test spin round the block and half way home died on me again walked it a bit tried starting it kicked over rode it home under very little throttle and made it - thinking i might take the shim out from under the needle and reduce my jets back to standard as when I gave more throttle to clear it when stalling she just continued to gag and stall


I'm getting the feeling I might need to replace my pick up coil ?
 
#13 ·
sure: I just want to be sure I am using my multi meter correctly and that I am sure it's read out's make sense when matching to the service manual - all my other readings match up and make sense except the pick up coil readings ( 380 ~ 570 ohms and getting a reading of .4 ohms this is starting to do my head in as even motorcycle mechanics are starting to be unsure???? I thought they did this for living..

what you got for me..
 
#21 ·
sorry about omitting the K in K ohms

I feel my ignition coils are looking healthy

I am still experiencing a weak orange spark in both plugs

now that I feel confident I am using the multi meter correctly and understand my readings I am going to re check my electrical components and will get back to you

really appreciate your patience - I am learning a lot through the process
 
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