I just checked Partzilla and they showed a B8ES for a 79 DT175... a few years ago I believe it was superseded to BR8ES there for that exact bike? I checked RMATV_MC and they still supersede to a BR8ES.

So maybe something has changed and the non-resistor NGK's are becoming available again?

Enduronut used to recommend the Denso plugs as an alternative to the NGK 

It would be interesting to see if the quirky plugs would act that exact same way in different bike.

We have no problem getting hold of NGK B8ES non resistor plugs here in the UK. Whether they are genuine or not is another story.

It would be good to try the dodgy plugs in the 175. Unfortunately it has an even dodgier piston..

Soon as you get the thing running good, the exhaust paint will turn grey/white and flake off.

.025" max gap on those plugs

and.... I grind a taper on the ground strap for a sharp focused spark
then grind back to 1/2 of center electrode so ground point is dead center of of center


cliff

I contacted NGK UK about this knock off problem.The head UK distribution and technical manager called me. He said that they are a problem but not so much in the UK.
" how's that like?" i asked . "Because they come from the plant in France and are tracked to the distribution point". that was his reply.

Well.  Here I am.  The one armed paper hanger...

To cut a long story short.  Smacking the gear carrier pins out of the reduction hub of a kessler axle on monday.
They are TIGHT and flush to the outside of the hub so you need a short drift to get them moving.

I found an old two inch diameter drain plug.  Perfect.  Proceded to swing the 16lb hammer and on the third pin, the drift proceded to fly out at great speed,  hit my right hand before flying across the workshop.
Hospital says poss hairline fracture but because of the swelling they could not be sure as xray was not clear enough.

Minutes before it happened i was moaning and groaning because I have man flu and was feeling sorry for myself.

So now right paw in a brace, two fingers taped together... And man flu..  . 

Have I ever mentioned my luck?

Anyway I took the opportunity to do a little lefty, one handed work on the 100.  Checked spark with new denso plug.  Fat spark.  Checked it with the old NGK.  Fatter spark.  Presumably because the denso has the U electrode that lets the spark grow inside.

Kicked bike over. Ran briefly but stopped.  Plug wet.  Crankcases flooded?  Dried plug, kicked bike over with  fuel off and plug out, but no real sign of flooding.

Plug in.  Ran for a second but stopped.  Plug still dry.  Could it be the starter circuit?

Removed airfilter and dribbed a little brake cleaner down the carb throat.  Kicked and she popped off second kick. Set a fast idle.

Ran it for five minutes and turned off the fuel to scour the crankcases and combustion chamber clean of any excess fuel.
Yup, rpms rose as she went lean and carb emptied.

Fuel on and tried again.  Second kick and she was away, sounding crisp off the throttle.  I ran the carb dry again to preclude any flooding issues and will resume tomorrow when she is cold.

Also checked fuel tap to make sure it shut off and opened correctly.  It did.  I did not want it allowing the crankcases to slowly flood overnight if faulty.

So we have always had a fat spark at the right time.
We have always had air.
We have always had fuel.
We have had no running from cold with heat cycled plug.... But it should.
once running it sounds crisp off the throttle and has a nice smooth idle.

I am thinking either cold start plunger or fuel lost just enough zing for a reliable winter cold start, but it came from a sealed container.
Around 50% of the fuel content in the tank was premix at 32:1 and the oil pump is conected.  It does white smoke quite heavily, but I recall RT100s being similar heavy smokers until the exhaust got hot.

Any other ideas?  It is plain weird. I know for a fact the reeds are in very good condition and the crank seals are new genuine.  The problem is not mechanical.

Bad hand is a bloody nuisance.




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Yep "choke" or enrich jet plugged(more likely)

cliff

Hand a bit better this morning.  Kept brace off last night and probaby rolled around on it during the night.  Must have been rolled back into the correct position.  Hurty but moves.  I can use it lightly.  Don't think it is broken after all.
Time to see if the bike would start.


Choke on, ignition on.  Kick.    Nothing but a feeble fart then nothing.

I resolved to brace myself today for a little more stringent outing in the freezing conservatory than my usual of late, run in, kick, swap the plug, get it running and retreat asap until the next test tactic.

Found the original carb and traced through the enrichment circuit inlet tube in the float bowl right to the plunger housing.
I got out my trusty welding torch cleaners and ascertained I could not clean out the drillings in their entirity.  Too many dog legs blocked off by ballbearings.  It had several 90 degree bends.

Removed the choke plunger and got a length of windscreen washer tubing to blow down the plunger orifice to see if I could feel air coming out the inlet tube.  I could.

All righty.  So if i did the same on the bike carb I should hear bubbles and the bowl vents venting air.

Removed plunger and blew down the plunger orifice.  No restriction evident.  Same as the other carb and air was coming out the vent tube.  No bubbles though, does this mean the float height is too low? 
Another thing to worry about and add to the mix.  My head is akin to a bingo machine full of floats, carbs, jets, sparkplugs, points and coils all whirling around and intermixing like a madmans kaleidoscope.
Which is going to pop out next?

Before I refitted the plunger I gave it a good polish with some grey scotchbrite and a good squirt of GT85.

Pull out plunger, fuel on, ignition on.  Kick.  Away she went first kick.
To coin a phrase from Dereck at VGG.  " Well I'll be dipped". ​​​​​

I have absolutely no idea what I did, but whatever it was, it seems to have worked.  I will try again tomorrow to see if it is cured, or is still toying with me.  No point in hiring the mariachi band until then.

I guess I can take those poor, maligned NGK plugs out of my conservatory bin bag now.  They are probably still good.