HT Leads on coils

[royhall]

The code on the 350/4 coils is FL703-12V. Cheers.

[AshimotoK0]

This is really a message for Roy. Had some fun and games and trashed a set of (faulty anyway) coils during the Ashimoto repair experiments. However, making good progress now with plan 'B' . Basically the TEC  coils are encapsulated in black thermoplastic material. The secondary coil  brass terminal inside can be got too quite easily BUT on one lead, if you try to de-solder the old HT  lead from the terminal, the heat melts the plastic, the terminal comes loose,and  the really fine wire from the secondary coil just snaps off and renders the coil useless. So I am just soldering onto the remains of the old lead.

Totally different with the Honda twins coils made by Nippon-Denso (yellowy/brown plastic body.). They are much easier to get to the internal secondary terminal because they are made from filled epoxy/ or thermoset resin which files/ grinds really easily. The HT lead conductor literally pushes into an internal pointed pin,no soldering. May solder it dunno yet. Was a bit worried that the replacement HT lead would not screw onto the metal -clad plug caps I just got from Germany but it's OK, after you create an initial hole where the conductor wire is, to start it off screwing in.

All 'TEC' coils  (four Cyl) around bit less than  5 Ohms ... Nippon-Denso's (twins) 3.8 Ohms..

Still need to find rubber sleeve 1mm or less wall thickness. I don't want to use heatshrink,  not flexible enough.
Progress and PICs to follow but on none of my coils, so far,  is there any coil failure, just HT lead fatigue where the HT lead comes out of the coil.

[royhall]

That's very interesting reading Ash.

As I have them do you think the DSS coils will be okay at 2.7 ohms with points, or are they going to eat the points and condensers?

Have been thinking of fitting a Boyer instead and have noticed they do a full kit including matched coils but it's really for a 400/4. If I go electronic that's the route I shall take.

Just weighing up before I fit the other coils, if I should return them to DSS and put the money towards the Boyer kit. I remember someone fitting the 400 kit to a 350 but can't find the thread now, some difference in the advance curve if I remember correctly.

What do you think Ash.

Cheers.

[Chris400F]

I think these may be the threads you are thinking of Roy.
http://www.sohc.co.uk/index.php/topic,8952.msg61112.html#msg61112
http://www.sohc.co.uk/index.php/topic,9062.msg62181.html#msg62181

[AshimotoK0]

Pretty sure the same setup on 350/4 as on 400/4 Roy. Makes sense to buy everything from Boyer although standard coils should be fine I think. Points with coils less resistance than standard sounds like bad news though as your points would arc and wear more with the extra current. DS pretty good on refunds & returns.

[royhall]

Taken the plunge and ordered the full Boyer kit including the coils off eBay. Strangely I couldn't find it anywhere else.

Will update the 350 Project thread with the details when it arrives.

Thanks guys for the advice.

Will get an email off to DSS in the morning and get a refund on the pattern coils. Will let them know about the resistance issue at the same time.

Don't know if that will change anything as DSS are only a retailer for these, and they are available in many other places.

[gtmdriver]

If you buy the Boyer kit you will need their coils too as Boyer specify a minimum coil resistance of 4 ohms.

As I posted earlier you can use the DSS coils with the Boyer system but you need to wire a 1.6 ohm ballast resistor in series with the power (black) lead on each coil.

I posted a few photos about the Boyer system a couple of months ago so if you search under my user name you should find it.

http://www.sohc.co.uk/index.php/topic,8979.msg61594.html#msg61594

[royhall]

Yeah found that post, very helpful. I have gone for the full boyer kit with coils as its really one of my existing coils thats failed. Thanks.

[royhall]

The new Boyer Bransden kit arrived today. I'm now in need of a little more help.

The coils are not direct replacements, and I assume that although its a £220 kit you have to make all the brackets yourself. Also I've no intentions, after spending 100's of hours restoring a bike to as new, of tie wrapping a digital box to a frame tube. I will have to manufacture a more elegant solution than that. Were not off to a good start.

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Thought I would see what the resistance is across the Boyer coils, and its only 1.4 ohms. What the hell, now I'm confused, I thought it was supposed to be over 4. My existing coils are 5.1 ohms, whats that all about. I assume its to do with some digital wizardry, and the fact the coils are linked in series?

Also are these standard (new) plug caps okay for this application, says something about 5000 ohm suppressed?

Beginning to wish I had just bought one genuine replacement coil instead.

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Any ideas anyone, and does anybody have a photo of the best way to fit this kit to a 350/400 four.

Saves me reinventing the wheel. You may have guessed by now that electrics to me is all magic and conjuring.

Thanks.

[gtmdriver]

No.

The Boyer kit that comes with their own coils is different to the kit designed to use the OEM coils.

1.5 ohm is correct for that particular Boyer kit.

The lower resistance allows more current to flow to produce a fat spark but the Boyer kit you have bought is designed to handle that current.

As to mountings I can't help you there. I'm the person who inelegantly ty-wrapped the box to the frame.

Stick with it though. You'll be very pleased with the final result.

Have you tried contacting Boyer as regards the mountings? They are usually very helpful.

[Chris400F]

Also are these standard (new) plug caps okay for this application, says something about 5000 ohm suppressed?

The NGK plug caps listed by DS are P/N VD05F (plugs 1 & 4) and XD05F (plugs 2 & 3).
The 05 in the P/N means the caps are 5K ohm resistance, the resistance being to do with suppression.
So yes, your plug caps should be OK.

[royhall]

Thanks guys. Will make up some proper aluminium mounts for the coils and digi box. Will post what the outcome is in the project thread, with some pictures. Cheers.

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