TOPIC:

Hi everyone, I am writing from New Zealand and have an issue I am sure some one can help me with. I am diagnosing a fault in a friends 1991 RC600 (I have a Nordwest) and I need some information.

I have checked the pick-up coil and have the correct resistance of 116 ohms and 115 ohms between the centre terminal (yellow/black) and both of the others individually but the manual does not suggest a test or a resistance between the white/green and yellow/blue. I have 235 ohms, is that normal or is there a fault here that could be causing the problem? Also, there is a gap between the rotor and the pick-up probes of about 3.5mm, is this excessive?

Thanks or reading and for any replies.
kiwisrv

Looking at the manual I think you should get near "double" resistance across the white/green and yellow/blue. You should however get no continuity between any lead on the pickup and earth.

That air gap sounds rather wide. I can't find a recommended figure but I used to set the gap on my 93 CDI Nordie with a feeler gauge to about the same as a plug (25 thou in imperial). So long as there is an air gap (after allowing for thermal expansion of the rotor) it should work and I used to find my tuned 604 would give a weak spark if it was much wider.

Ignition coil OK?

Check the kill switch isn't shorting. You should also be able to eliminate the ignition switch by disconnecting a lead somewhere but I can't remember which as it's been 18 years since I had to do it a track day when I forgot my key (it won't work on induction ignition models).

Otherwise I suppose it could be the CDI unit

Thanks for that 72degrees, no there is no short to earth in the pick-up and I suspected the higher resistance was correct but needed to check with someone in the know, yes the CDI has been replaced (diagnosed elsewhere but not the cause), however the air gap had me concerned as it is really wide. I am pleased you confirm that suspicion. I also noticed that the base plate of the pic-up mounting has been modified to move it closer yet it still has the massive gap so I suspect it is not the original and may be adapted from another make. I will check the ignition and recheck the kill switch but I think they are o.k. Thanks for your help I really appreciate it.
kiwisrv

since when the bike did not start?
Did you (or your friend) get it still not starting?
Soemtimes someone did mix up parts of the 2 ignition systems.

I suppose it's an 'old' RC with metal tank and a CDI system.
For example, mounting a flywheel from a inductive system will end up in not starting
I also found out this by the hard way
So maybe it's worth to compare the Gilera spare parts numbers.

As you have 3 wires at the connector there are 2 coils in the pickup and you should get the doubble resistance like Pete described.

The gap is somehow far away from everything i know.
I did not own a RC, but Gilera claimed 0,7 to 0,9mm for the Nordies.
I also use this on my Saturno which should have more or less the same ignition system as you.

ciao Joachim

PS just found the technical advice from Gilera Germany
Every 600ccm engine should be adjusted to this gap at the pickup when having problems to start
I will try to send a copy this evening

Joachim wrote:

The gap is somehow far away from everything i know.
I did not own a RC, but Gilera claimed 0,7 to 0,9mm for the Nordies.
I also use this on my Saturno which should have more or less the same ignition system as you.

ciao Joachim

PS just found the technical advice from Gilera Germany
Every 600ccm engine should be adjusted to this gap at the pickup when having problems to start
I will try to send a copy this evening

Phew! I wasn't far out at 25 thou then but perhaps a little on the tight side.

Does sound as if either the rotor or pickup may be 'wrong' and so don't match. Perhaps modifying it to get an even smaller air gap might work if that's possible? Are the 'lumps' on the rotor for the induction ignition system also differently timed? I seem to remember they are roughly in the same place having owned a CDI and induction Nordie at the same time and changed belts on both. The CDI one was more sensitive to the pickup gap in my experience. One time after a long winter not running the tuned 604 I had to clean up some corrosion (yes rust!) on the rotor and polish up the pickup pips before it would start.

Thanks folks for the helpful advice.
The bike was purchased not running by my friend and we think it is the only one in New Zealand. Yes it is an older machine built in 1991. I have no idea how it got here but we are both passionate about getting it going. I was thinking over night that I might "modify" the pick-up some more to close up the gap. Now I will also get the numbers off the rotor etcetera and compare them, any idea where I can get a reliable parts listing?
At the terminal end there seems to be a repair covered with shrink wrap so I suspect the pick-up may have been replaced with a non-standard unit, in this case modifying the mounting bracket won't be devastating if pick-ups are still available for purchase somewhere.
Just went and photographed the gap and I may have over estimated the gap but there is genuinely a 1.5mm gap between the pick-up probes and the induction mounds on the rotor. Judging by what you have both said this could very easily be a contributor to our problem. I will have a play and let you know. Thanks for your help.