Question on ignition coils - 1979 Ducati 900 Replica

[Blacklightning]

Hi,

I'm restoring a 1979 Ducati 900 replica (MHR) and have come to reassembe the igniton coils.

I've cleaned everything up, had the alloy frame parts for the assembly polished, restored the bright zinc parts and have bought new NGK plug caps. All the connection terminals I have cleaned and polished with a dremel - so it's looking pretty nice to me.

This question is in relation to the HT leads, They go into the coil and are sealed in some fashion with a material which has set hard and brittle around the cable. I was wondering if there is a recognised way of getting these ends cleaned and remove the HT cable so that it enables replacing of the HT leads as a precaution - whilst the bike was firing and running fine when I took it apart, new fresh HT cable would probably be a good idea.

But how to get the ends out of the igniton coils?


They are Nippondenso 029700's - white/cream colour.

I'm sure someone has come across this before

Any advice much appreciated.

Regards

Stuart

[Craig in France]

Hi Stuart,

In one word: Don't (bother). They're most likely working fine.

But, if you really must, this is what I have from John Wilson of IIS fame:

"Replacing HT cables on Nippon Denso Coils
(pinky-biege colour, stamped 028700.)

First, carefully remove the epoxy resin around the HT cable entry point on the body of the ND coil. You can do this, for example, by using small side cutters. Take care not to damage the body plastic.

There are two parts to the HT lead:
• the inner HT lead/copper wire with insulation cover
• an outside thin sheath.

Pull hard on the HT lead until it comes out of the coil body tube. This will leave the outer sheath still inside the coil tube. Break this bond by carefully pushing a screw driver down between the sleeve and inner bore of the tube until you feel the remaining epoxy, then continue working around the sleeve until it frees from the bore. There is a standard spike termination at the end of the bore.

Insert a good quality copper core HT lead of 7mm diameter (8mm will not fit) into the bore (tube) until is stops. Then secure the new lead to the ignition coil body using a good quality silicon sealant or epoxy.

Try not to use building grade silicon as it cures by liberation of acetic acid which attacks copper components. Use 738RTV, if you can find it at the local electrical wholesalers; or at least a neutral cure silicon which is becoming more available from hardware stores.

Once done, terminate the HT leads using NGK spark plug covers with 5.0K ohm suppression resistor for clean firing of the spark plugs."

HTH.

Craig

[Blacklightning]

Hi Craig,

OK will take your advice - the bike fired and ran perfectly when I bought it in October 2011, so there is every reason (yeah, I'm a issupressible optimist) that it will fire and run after I have rebuilt it.....

I had thought best left well alone but wanted to ask those with experience here....

So far I have very little experience of this machine....never even ridden one yet.

But very soon now, she is up on her wheels, brake systems all done, now onto the re-wiring.

I hope to be able to start her in April/May - fingers crossed.

Thanks for all your help Craig, posts replies most welcome.

Stuart

[Craig in France]

The other thing, Stuart, is that, should the need ever arise, they're relatively easily available anyways. 'Cos they were used on contemporary Suzuki GTs. So go, for example:

http://www.ebay.co.uk/itm/gt380j-k-ign- ... 4ac28216d4

Plus Steve (for example) will sell you a Dyna replacement, should you not be bothered by originality.

Have a blast on your first outing . And let us know ...