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No Spark, help please!

Posted: Mon Apr 02, 2012 8:31 am
by steve H

Hiya everyone,


 


bit of a problem here. After replacing my throttle cable (necessitating replacement of my Magura throttle and brake lever with Minda ones) I found I could not start the bike. Further investigation revealled no spark at the plug. The battery has just been charged, the fuse is fine, the lights work. Everything looks alright.


What may be the cause?


I recken the coil, but any other ideas would be most welcome.


 


Ta


 


Steve


No Spark, help please!

Posted: Mon Apr 02, 2012 9:34 am
by Midge

I don't suppose the engine cut of switch or wiring by the throttle has been disturbed? No I'm sure you have checked that.


 


No Spark, help please!

Posted: Mon Apr 02, 2012 9:38 am
by Alan R
Hi SteveH---------- round 2 ( lost the 5-mins worth of typing just now)  Assuming all was well beforehand then somewhere along the line you have done something / not done something tnat's given this fault.  Why do you think its the coil ? You can test the coil independantly by removing the bike's leads and connecting}-- the battery---coil----points(closed)----With the plug properly earthed then flick the points open and you should get a fat, blue spark. Also, with a test meter check to see if there is a feed from the ign. switch to the coil (turn the ign switch on). Why did you need to change to Minda units ?? Have you missed a connection somewhere ?? Is the wiring loom trapped on the handlebars etc ??  I don't mean to lecture but  just a steady re-run of what you did will probally give you the answer. Best wishes----

No Spark, help please!

Posted: Mon Apr 02, 2012 9:51 am
by Alan R
Hello Midge & SteveH---a few years ago , on my Bullet '65  and on my way to a mid-Summer bike-fest when a wasp flew near my visor (a 60mph wasp at that !!). I casually brushed it aside ------ and the bike faultered and slowed down-----and stopped. A quick check showed no power at the points so I rigged up a jumper lead, getting  the power direct from the battery----and had a good rally during which time somebody said to me " How do you get the bike running with that kill-switch turned off??"----------------------DOH !!!!!!!!------------------- I wear gauntlet type gloves and the long cuff must have caught the switch when I swiped that wasp !! Also, this was my first "Modern " bike to have a kill swich on so never even thought about it. Jumper leads pulled off---switch turned on and Alan R lights up the evening with his blushes. HAR HAR HAR. Serves me right too. 

No Spark, help please!

Posted: Mon Apr 02, 2012 9:53 am
by apparently lucky eddie

I always found the quickest way to check the coil was to find an idiot to stick his finger in the plug cap while I gave the engine a good kick. Assuming each expletive was worth about 6,000 volts that meant 4 "F" words meant the coil was pretty good : )


No Spark, help please!

Posted: Mon Apr 02, 2012 10:06 am
by Alan R
Hah!! Does that mean LUCAS now have a new "F" rating system for their HT coils ?? Try using a Harley rider's finger---they ALWAYS acknowledge your friendly nod as you cross paths---don't they ?? I nodded at an oncoming biker last year----turned out to be a Police Constable "going about his lawful duties upon the Queens Highway"  OOerrr.  Sorry Steve--can't help much with the problem but a little humour might be useful. By the way---when you first realised the bike wouldn't start can you tell us what Anglo-Saxon words of distress you summoned up ?? (Purely for future reference and Apprentice Training you understand).                                                         Oh yes----- ultimately you might want to borrow my 2lb Engineers ball-pein hammer ??

No Spark, help please!

Posted: Mon Apr 02, 2012 10:34 am
by steve H

Just to clear up things a little, my bike (bullet 500, 1995) has never had a kill switch. There are no electrics on the throttle side apart from the front break switch.


I've changed the throttle from Magura to Minda because the Magura throttle was getting very worn out. New throttle cables will not fit anymore, so rather than have to have new cables specially made, I got a second hand Minda throttle from our hosts.


I've earthed the plug on the barrel and given it a kick, but no spark (tried 2 different spark plugs too!).


No Spark, help please!

Posted: Mon Apr 02, 2012 11:05 am
by Alan R
Hi Steve--- yes, that helps narrow things down a bit. Just a thought----remove the HT cap and see if there is a spark from the end of the HT cable ?? Have you tested that wire from the Ign. switch to the coil for power ?? Try a 12v bulb (sidelight type is ideal) from each of the coil terminals  to earth---- should light up, dim or bright doesn't matter. Did you remove the fuel tank at all ?? Check the ign. switch connections for security. It might just be coincidental that the Ign. switch has decided to go "open circuit" internally right now ?? so you really do need to see if there is a feed actually AT the coil, OK 

No Spark, help please!

Posted: Mon Apr 02, 2012 11:29 am
by Norm
 Test light is good here, with the ignition on and points open you should have power on the points spring, if not trace back to the coil and work your way back to the ignition switch

No Spark, help please!

Posted: Mon Apr 02, 2012 11:54 am
by steve H

Thanks Alan (and Norm). I will give that a go after work tonight.


 As for the Anglo-Saxon used, no need, I expect this kind of thing every now and then. What I want to know though is why when one things goes wrong, other things start going wrong too. Are they just keeping each other company? Does the bike know that its lovely riding weather?