Won't start, what have I done?

[BillyKnight]

Hello,
I bought a VFR / NC30 about a year ago and finally got it back into one piece and running pretty well back in September.
Last week I decided to get it running again but the battery was a bit flat and it wouldn't even start with a push. The gas in it is about a year and a half old but it ran fine on it in September and I have recently topped it up with fresh. Then I decided to help it along a bit as I had a car battery in the shed but I stupidly connected it the wrong way round, idiot! I know.
So there were a few sparks on the leads and the main 30A fuse on the bike blew. The ignition was off this whole time.
Since then it does not want to go, BUT there is a fairly good spark visible at the plugs. I got it to go today on easy start but it just goes on that and won't pick up on the carbs.
Have I wrecked the coils or Igniter box, or what? someone else out there must have done it. I know it was dumb but it all happened pretty quickly and now I just need to move on and get back to where I was!!
Any advice much appreciated, thanks.
Billy.

[Morespeedvicar]

Hiya,
if its sparking when its cranked then i would of thought the electroincs are working. Try taking the sparkplugs out and cleaning them, there really small and get wet real easy especially with old petrol.
Maybe worth cleaning the carbs out while your playing.......

Cheers
Ian

[wullvfr]

hello-

if the plugs are sparking well then your electrics are fine,the fuse is there to protect the system in the event of things like what happened,because there is a good spark then i would put my money on it being fuel related.

chances are the carbs are needing a good clean.....

when the battery is fully charged how good does it start?does it take a while or does it turn over no problem at all......

are you using the correct method for starting?choke on and no throttle!!!!!!!


william

[BillyKnight]

Thanks for the comments guys,
I have been out this morning and pulled off the carbs and removed the float bowls, all perfect. Put back together and with new petrol still amazingly dead.
I am quite sure the igntion has been damaged and I am guessing the coils as there is still a spark but not strong enough to fire the mixture in the cylinders.If the igntion box was damaged I think there would be no spark at all. I am embarrassed to have been so stupid, aaargh!
I wonder if there is anyone reading this living in or near to Southampton that could try one of my coils on their bike to see if good? Give me a call if that may suit, 02380 666639. Its a damn easy way to getting a few free beers!
thanks again,
Billy.

[wullvfr]

im guessing it's not starting at all!!!

next time you try and start it and it doesn't take a plug out and see if it is wet with fuel,just to be sure it's getting fuel....this will also let you know for definate that the mixture is not getting burnt.....

do you have a multimeter?

the downside to the coils is you can only really test them for resistance and not much else,but if you are certain they are faulty then they are usually available on ebay for pennies.......but personally i would try coils that you know are working perfectly and see if it makes any difference.

if all 4 plugs are sparking weakly then chances are the problem lies somewhere else,like the cdi unit like you say.......im just thinking what's the chances of both coils playing up or being affected by the mishap.

if you have a multimeter then i would test the coils first



william

[Morespeedvicar]

Hi,
have you taken all the plugs out and cleaned them? try heating the plugs up with a blow torch to burn off old fuel and then clean them (when there cold like..lol), i would still think it not that serious if its sparking.
Maybe take all plugs out, leave it over night to dry out.
Giv it all a good clean, and try a bit of easy start down the carbs ( im assuming you can still get easy start?) without the tank on.

Cheers

Ian

[Sligeach]

when you had the carbs off did you clean them with solvent and an airline or just a visual inspection?
is the choke linkage fully functional?

[BillyKnight]

Hello again people,
when I pulled the carbs apart I just swilled out the gas and put them back together. They are obviously fine, no dirt or anything. The plugs are nice and clean, and you can smell gas coming out of the pipe. Not the best spark in the world but it is there. Every now and then it goes bang out of the pipe as a spark on the valve overlap part of the stroke fires the fuel in the pipe but it won't fire under compression.. Yes choke is working fine.
Its ignition! What ever the problem is, it is total. This bike is quite dead.
I measured the resistance in the primary and secondary circuits in both coils which came up OK, also measured the pulse coils resistance, also OK, so am now looking at the Igniter box. I will get one and swap it over and see how we go.
The bike has a new battery which spins it over very well, maybe I should just put it in gear and ride it on the starter!
Billy.

[CMSMJ1]

I reckon new plugs are needed - theya re fickle and delicate little buggers and even though you get a spark out of the heads it might not be strong enough to fire when under compression.

The repeated starting attempts can also kill them by flooding.

Try no throttle and 3/4 choke and buzz it for 20 secs a time - if you can get any life then it might catch up and start.

My 20p is on dead plugs...

[wullvfr]

My 20p is on dead plugs...

as much as that

2nd that,if the spark is there but not very good as you say then try replacing them first.........or if you have any other plugs kicking about put them in the caps and see if the spark is any better.

if you can easily get hold of another cdi unit then try it and see if there is any difference



william