Ignition pulse generator. (Pickup)

[connor]

Hello All

Recently had a starting problem with my 94 Magna which has now been resolved by fitting a replacement Igniter unit. ( Thanks again to Terry).

However during the course of trying to diagnose the problem two points of interest came up..

1)   At one point I suspected that the ignition pulse generator was at fault because I was getting a low resistance reading through it.  The manual states that when checked with an ohm meter the units resistance should be between 450 and 550 ohms. I was getting a lower reading of 320 ohms. At that time I did not know if this lower reading was enough to cause a starting problem.  Anyway after further checking I sussed that the igniter unit itself was the culprit and sure enough on fitting the replacement unit supplied by Terry the bike fired up instantly and runs perfectly now.

So my point is that although the pulse generators resistance reading was low acccording to the manual it is actually operating fine. So if at any time you have to check your pulse generators resistance it may pay you not to condemn it outright if its resistance reading is lower than normal.

2)  I had to replace the bikes starter clutch unit cos the original had cracked. I obtained the new unit from Bike Bandits and duly fitted it. The engine cranked over ok but ran erratically. Anyway to cut a long story short I found the following fault on the new starter clutch itself.

Around the edge of the starter clutch cover there are 9 raised metal segments, I'll call them nodules. As the starter clutch spins round these nodules trigger the pulse generator.  These nodules are pressed out by a stamping machine in the factory. 8 of the nodules were standing proud of the clutch cover by exactly 2.5mm. One was only proud by 1mm.  This one had not been pressed out correctly and was not triggering the pulse generator when it should. This in turn meant that the igniter unit was not receiving the correct sequence of pulses which resulted in ignition timing being all out of sync....hence the engine ran erratically.

I carefully managed to prise out the nodule to 2.5mm and the engine ran perfectly. As a tip I can only suggest that if you have to fit a new starter clutch then please double check that these nodules are all equally pressed out to 2.5mm.  It was a bit of a b...... and meant engine cover off and on several times before I sussed the problem.

I am a motor car mechanic and as such have access to tools and test equipment in my workshop so am lucky in as far as I was able to determine the fault myself but I suspect that maybe an average biker might have been given more than a headache if he'd fitted that starter clutch unit. So like I said check those nodules before fitting a new starter clutch and save yourself a lot of potential hassle.

Regards to all...Connor.   

[hootmon]

Conner -
I also replaced my start clutch with one off of e-bay yesterday. Looking at my original starter clutch I can confirm that each of the nubs seem to be the same hight, so good catch on your part, the lower nub probably would have escaped most peoples inspection.. It probably got dropped somewhere along the line.

[Chad in Michigan]

connor, that is what i was trying to tell you in my posts about the starter clutch. it could have been out of alignment at some point, or those things that trigger the pickup. i bet you you're old ignition module may still be good. good catch

[lragan]

This is very valuable info, Conner, and needs to be preserved in a "hints and kinks" or FAQ somewhere where it won't fade from memory.

Terry, are you keeping such a cache of useful info?

[connor]

Hi Chad....The original module/igniter/ECU has definitely failed. Tried refitting it after the starter clutch fault was rectified and it would not perform..Starts instantly with the replacement unit supplied by terry.

It seems I was very unlucky..

1)   Lightning damaged the Igniter / or it just decided to fail at the same time as the lightning strike..???.....Strange though that a computer and a tv were damaged in the workshop where the Magna was parked. I was in the workshop at the time of the strike and the air sizzled with static and my hair stood up...It was a very strong burst of static.

2)  Bike Bandit sent me a faulty Starter clutch unit.
The offending nodule on the clutch did not look like it had been dropped and in doing so depressed it, but rather it had not been punched out correctly by the factory. With a very small metal chisel and small lever I had to break the partially pressed sides of the nodule's metal in order to open it out to 2.5mm.

Electrickery can be fun...!!!!!

[connor]

Perhaps my luck is changing...

On e bay uk I found someone who is breaking a 94 low mileage Magna. So for the equivalent of about 300 US dollars inc postage to Cyprus I have bought...

A complete set of carbs. ( Have seen the price of new diaphragms..! )
A starter solenoid.
2 ignition coils.
Fuel tank on / off tap.
Igniter/ECU unit.

30 day money back warranty. Have dealt with this chap before and he seems quite genuine. 

Here in Cyprus am out on a limb as it were with regard to Magna used parts so when I see parts like this on offer I think I'm being wise in grabbing 'em quick.

[TLRam1]

This is very valuable info, Conner, and needs to be preserved in a "hints and kinks" or FAQ somewhere where it won't fade from memory.

Terry, are you keeping such a cache of useful info?

Thanks for the heads up Lawrence, I will.

As said before Connor, valuable info and may not have been picked up by many of us.

[Bill Arche]

My 1994 Magna ignition pulse generator also reads low resistance, 304 ohms. Engine misfires under load. Both Coil primary and secondary resistances ck ok. Spark plug caps ck good. No visual sign of insulation breakdown. New spark plugs no improvement. Igniter?