Correct coils? - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 13 (permalink) Old 10-09-2019, 10:56 AM Thread Starter
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Main Motorcycle: 65 t120r 650 Bonneville
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Correct coils?

My '65 Bonney has two 48mm 6V. coils which I suspect are bad. I have been searching for replacements for some time now with no luck. Finally I found some at classicbritishspares. Problem is they have a statement that reads as follows. "Today we have new Lucas coils and Cycle Craft brand coils for sale all in this single listing. We stock 6v and 12v coils both the smaller 40mm (Triumph & Norton style) as well with the larger 48mm types (BSA style) ready for installation." So my question is, do I have the wrong (BSA) coils installed? Should they actually be 40mm? Other than size, what is the difference between them? My parts book lists the coil as #45152 MA6. Once I get this figured out I will hopefully get the old girl started after a 49 years rest.
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post #2 of 13 (permalink) Old 10-09-2019, 11:54 AM
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Why do you suspect your coils are bad?
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post #3 of 13 (permalink) Old 10-09-2019, 12:13 PM Thread Starter
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I've ohm tested them with multimeter and also pulled plugs and grounded them to engine. No spark when kicked over. Fully charged battery. Meter readings were sketchy on ohm readings from primary to secondary. Re-wired everything according to workshop manual diagram initially. So I'm assuming.
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post #4 of 13 (permalink) Old 10-09-2019, 12:23 PM
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Quote:
Originally Posted by bonneydude View Post
......Meter readings were sketchy on ohm readings from primary to secondary......
Primary resistance = ???????????? positive to negative reading
Secondary resistance - ???????????? positive or negative terminal to center reading


I just wnated to ensure that we're on the same page. 8))

Owner Very Early 1972 Triumph Tiger 650 TR6R OIF
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post #5 of 13 (permalink) Old 10-09-2019, 12:34 PM Thread Starter
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Both. Positive to negative OK. Secondary little or no reading.
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post #6 of 13 (permalink) Old 10-09-2019, 12:38 PM Thread Starter
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I wasn't sure of ohm setting on meter, so I checked at different settings. Same results. Lunchtime now, back shortly.
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post #7 of 13 (permalink) Old 10-09-2019, 01:17 PM
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Main Motorcycle: 66 Triumph TR6
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Pre 1966 I believe both export and home market bikes used the large Lucas MA6 coils. From 66 on export bikes used smaller (Sigma?) coils, these required a different mounting system that used a folded metal plate bolted to the frame and the circular coil bracket bolted to the plate. The MA6 coil has a bracket more like you find on a motorcar bolted to the frame.

I can probably sort some pictures if required.

Rod
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post #8 of 13 (permalink) Old 10-09-2019, 01:51 PM
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According to the parts books

The Larger Lucas 45152 m6 coils are fitted between 63 and 65 to the unit T120.

The ‘Genuine Lucas’ coils at Classicbikespares are made in India Genuine Wassel copies.

There are these on e-bay USA at the moment, and might be a better bet.
Item numbers.
161977960552
161977960212

Regards
Peg.

Quick fixes are named after how long they stay fixed, not how long it takes to make them.
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post #9 of 13 (permalink) Old 10-09-2019, 02:32 PM Thread Starter
Grand Prix 500
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Thanx folks. Ebay ones look pretty iffy. Not going to replace old ones with different old ones.
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post #10 of 13 (permalink) Old 10-09-2019, 02:39 PM
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My T140 has PVL coils - don't know if they will do your size
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