The condenser is 12mm OD x 26.5 L.
The other condenser is 17mm OD 
The three wires are actually source coil ,Ignition coil and contacts. I pulled the sheathing back and found more than what i was looking for. What looked like the source coil wire was actually shrink wrap. That's my solder on melted in with the original .

 


I found that Bowden cable type wire when i ran a new ignition coil wire in. That's supposed to be new old stock.
Something tells me that's not genuine Yamaha NOS wire.

If I can remember correct I used one for a Honda ct70 for my ht1 but my stator only had 2 coils. I found one that might work for you

I've been scouring docs to see if I can find an HT1b with 3 stator coils...  It seems the 3 coils started with the 72 LT2?

It's possible you have a JDM model that's a little different than the US models or someone has swapped parts over the years too... 

Whatever it is, that may be why the "normal" condenser doesn't fit. 

Great stuff thanks. I managed to get one from one of the other members and fitted it today.
It's worked .
Now the spark quality is much better and blue instead of orange.
I went down this rout as i was fault finding . The motor has started cutting out on idle when it gets warm. When i fitted the condenser the bike fired up first prod and ran much better but i hadn't located the fault and it was starting to get worse. While i was running the bike with the case off i could hear a squeaking sound so started looking and listening . Checked my work to make sure nothing was touching the rotor. All okay. With each item i removed, i kicked the motor over checking for the sound and finally arrived at the problem . I looked at the crank seal and saw it straight away. The seal had popped out and the squeak was pressure blowing past the lip on the crank seal. Not a genuine item. It came with a pack of seals i got with the bike .Now i know i can get that one in the UK from Fowlers Yamaha so there'll be one here tomorrow .
Once again thanks for that.

Glad it worked out ok, Dave! 

Hahaha, had to laugh. the seal i got with the bike . It's the same make as genuine . ATE !