I am rebuilding a DS7 
while not an enduro, it’s a Yamaha and a 2 stroke, albeit with 2 cylinders. 
I looked up spark plugs and found these Nippon Denso plugs.  I’ve never seen plugs of this style.

do they perform as well as standard electrode plugs?  Do you happen them? 

any experience appreciated, thanks I am rebuilding a DS7 
while not an enduro, it’s a Yamaha and a 2 stroke, albeit with 2 cylinders. 
I looked up spark plugs and found these Nippon Denso plugs.  I’ve never seen plugs of this style.

do they perform as well as standard electrode plugs?  Do you happen them? 

any experience appreciated, thanks

Was that the original plug type Yamaha used?  I don't remember them in Yamaha's but Kawasaki was big on side and surface gap plugs.  NGK had a "C" instead of nothing or "S" at end of part number...  B9HC instead of B9HS

The idea was to "unshroud" the spark which was supposed to make for better combustion?  I remember them fouling a lot easier and no noticeable difference in performance. 

Just when i thought i'd seen it all--i've never seen one like 'that'. Thanks for posting. looks short reach. Were DS7's still short reach.

I'm surprised Morley hasn't seen them...  Kawasaki used them on a lot of the smaller displacement two strokes into the mid-70's along with surface gap plugs on the CDI models. 

 

I was stuck in a Yamaha shop lol so no out of the ordinary stuff with them. Did see my first surface discharge plug though when ended up working on a Kawy 500 triple, the first go-fast model & damn scary it was too haha. I do remember using KLG-FE220 race plugs years ago with adjustable side pin gap & i think there was an adjustment special tool for doing the gap although i never adjusted one. Had to go into deep memory recall to find that lol. But i've got a box full of NGK BUE plugs that are surface discharge. Ran one in my 360 for a bit & might still be in it.

That makes sense.  I only saw them because my best friend's dad was huge Kawasaki fan.  Yamaha and Honda were the most common bikes in my neighborhood with Suzuki a distant 3rd and Kawasaki 4th...  Which coincides with which dealerships we had in our little city. 

We went into Orange County with friends dad to get Kawasaki parts..  but usually he just brought parts home with him.  He worked as a mechanic at Disneyland. 

Hi All -
I had stepped away for a few days, thanks for the interesting comments.
Mark, the original plug was B8HS and my research led me to this plug as "equivalent" which I hope it is or I have 10 paperweight that I can pass out to this group!
This DS7 is a very cool machine...another dessert rust bucket that I am bringing back to life.  I lucked out with a good crank and bearings and bores that I honed and re-ringed.  Clutch was disintegrated and so many parts hard to find.  The horizontal "split" cases were much easier to work with than a 1 banger with vertical split.  Many of the rubber bits are very hard to find/expensive.  

The wheels are pretty rusty, I am thinking about respoking/rerimming - how hard could this possibly be!  Any tips on this appreciated.

God bless all our fallen troops

There are companies here in the UK that sell reproductions of many of the rubber parts - eg Sumo Rubber, Yambits, RDLCCRAZY. I'm sure that there must be places in the US doing the same thing (Clauss Studios, HVC?).

If you haven't done so already, use Partzilla and CMSNL to see which parts were shared with other models.