| Author |
Message |
Spike
| | Posted on Wednesday, November 06, 2002 - 6:08 pm: | |
hello,
I'm having trouble with my ignition…
Coils are good, tested with or without the plug cap, points are OK, no broken cables anywhere, juice flows to the coils, but... no spark (with or whithout sparkplug, sparkplug cap), nothing!
I'm getting baffled here, anyone can help?
Cheers,
Spike |
Spen
| | Posted on Wednesday, November 06, 2002 - 6:41 pm: | |
Are the plug leads OK? |
Spike
| | Posted on Thursday, November 07, 2002 - 8:02 am: | |
Yes, plug leads are OK. I can test secondary of the coils though them (with or with plug cap). |
Spen
| | Posted on Thursday, November 07, 2002 - 8:17 am: | |
I had a similar problem with my B40 trials bike, power to the coils and everything seemed in order, there was even a spark to the plug, it still turned out to be the plug lead, when the plug was out and resting on the engine it sparked but when it was back in it's proper place, it didn't, the problem was that there was a break in the lead which joined itself up when the lead was bent, ie; when the plug was out of the engine and resting on the cylinder head for testing.
Is there some sort of kill switch in the system which you don't know about?
Earthing points alright??? Have you painted the frame recently and coated an earthing point with paint? Might require cleaning up if you have.
Bit of a puzzler, it generally turns out to be something simple, I hope so!! |
Adrian
| | Posted on Thursday, November 07, 2002 - 11:44 am: | |
Spen's point about the paint is a good one. SO many times, restorers have problems with 'the electrics' when really it is a bad earth connection. Check it carefully, and then recheck!
Also, make NO assumptions about parts when working through the system. As a mechanic I got call-outs and problems all the time where the person 'knew' that this bit was Ok so it must be something else.... etc
If you have a supply to your points and capacitors, and they are opening and making and braking the circuit(can you see sparks across them? - If not, there is your problem) AND then the feed goes to correctly working (and Earthed)coils, IT HAS TO WORK! Its Physics, it can't do anything else!
So either, a component that you think is OK is knackered, or the electricity supply is not going where it should.
keep us posted
Adrian
PS A possible idea, but is the battery a good one? if it is very flat, all the generated electricity goes to that and there is not enough juice left for the ignition. When a T20 battery is totally flat, to start it you disconect the battery, kick it up, and then reconnect before you blow all the bulbs! |
Spike
| | Posted on Thursday, November 07, 2002 - 4:20 pm: | |
My T 20 is all original (hence my search for a blue LH cover), with the exception of an extra earth to the rear light. (when you brake, you get a more visible brake light).
Now, two things:
1)I will change the leads, but how do you do it? They seem to be cast into the resin of the coils. I dismantles T250 coils and there was no screw on the coils for the lead. As if the lead was built into the coils.
2) I have no arcing at the points (or sparks at the plug (or lead)). To me this is normal, ie aren't the condensers meant to prevent that?
Thanks for all your posts,
spike |
Adrian
| | Posted on Thursday, November 07, 2002 - 5:13 pm: | |
Forget the coils! There should be a spark across the points.
The condensors reduce arcing and make the spark at the plugs stronger, but don't stop all sparks. Put your voltage tester across the points and see what it reads when open and then when closed. (With the ignition on of course!) You should get two readings of about zero and 12V. If you open and shut the points several times with a screwdriver you should get sparks at the points and at the plugs. As you aren't, you have a supply problem from the battery to the points. To prove this, bypass the old wires. Get two long wires from the battery, earth the negative one and join the positive one to where the condensor and points connect up. (However, it is possible that your fault is at that junction as if anything there is connected to earth, it won't work.) NOW open and shut your points and see what happens.
Let me know
|
Spike
| | Posted on Friday, November 08, 2002 - 5:10 pm: | |
Good news! for an unknow(!) reason one point started sparking. at the points and at the plug... ye gods! but the other one shows 0 Volts either open or closed. What could that mean? wires from alternator are not broken, and juice arrives at the point but is not prsent at the tip of the points...
btw, thsnks to all of you guys, this is REALLY making a diff.
Cheers,
Spike |
Spen
| | Posted on Friday, November 08, 2002 - 5:47 pm: | |
Have you run a file across the points?? Clean 'em up on their faces. |
spike
| | Posted on Friday, November 08, 2002 - 6:30 pm: | |
Yep,battery's full, points are filed, checked for gap and cleaned umpteenth times. they're dry.
As you said, it MUST be something stoooooopid and the thought of it makes me mad...
Thanks. |
Adrian
| | Posted on Friday, November 08, 2002 - 6:51 pm: | |
OK, you reckon that there is a supply to the second set of points, but zero volts across them - that means that the supply is either NOT getting there, or, that the condensor/points connection is not insulated properly from ground, thereby stopping the points from doing there job. RECHECK that there is a supply to these points. If so, then the side of the points that should be insulated from Earth (the moving bit), isn't insulated, and if it is, your points may be CLEAN but have they got an oxide layer on them? Dissemble and clean/file again.
Keep us posted
|
spike
| | Posted on Tuesday, November 12, 2002 - 5:39 pm: | |
Hooray!! (sort of...)
After much hair pulling and reading and rereading your advice, i just dismantled the whole ignition sys down. And OF COURSE, these points (moving bit) were juuuuuust touching the earth.... Thanks a lot guys, this saved the last neurons i had!
Never trust parts not installed by you, i suppose.
Anyway, the little T fired away this afternoon, great white clouds and all!
But, just to keep this thread alive:
the beast just revs right up (i m running without airbox, for accessibility's sake) and i have to choke with my hand to about 3k revs. To me, it means massive air leak somewhere... (carbs are clean,set up per the rules, etc..)
if i put on the choke, there is a difference...
Can i have your opinion, gentlemen?
Many Thanks,
Spike
(photos shortly on your site, Adrian) |
Adrian
| | Posted on Tuesday, November 12, 2002 - 7:06 pm: | |
If it is over revving, with or without airbox, then your slides probably aren't returning to the bottom. So, either your tickover adjuster mechanism is set too high, or your slides aren't returning RIGHT to the bottom of the carbs. |
spike
| | Posted on Friday, November 15, 2002 - 5:18 pm: | |
This is to Thank Allllllll of you who gave helped me: the little bugger is now running. A few more tweaks and getting the neutral switch to work (prob just dirty) and she'll be fine.
Many many many thanks.
Cheers,
Spike |
Spen
| | Posted on Friday, November 15, 2002 - 7:17 pm: | |
Excellent news, well done mate. |
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