Same problems, but thought I'd ask what's my next step

The front pot oils up if let idling too long when cold. Generally the front cylinder doesn't run cleanly up to 3.5K then everything smooths out. No problem at the top end and will rev through to 11.5K no problem

The list of things tried so far;
top end (replate etc)
new coils
new pickups
cleaned carbs and jets air-lined
tried an iridium plug, which worked ok for a couple of weeks
switched to super plus fuel
adjusted the idle to 1200 when warm
just cleaned every contact, but haven't put in new plugs yet

I did notice stands of wire collect on the pickups when they were replaced. I guess the only place the could have come from is the generator windings. I haven't checked again recently.

Since adjusting the idle the bike fires 1st kick, idles at 3-4K revs then settles to 1200

I did take the bike up to Gibsons in the summer for them to look at, but no success. The carbs were taken off & cleaned, but not re-balanced

When you rebuilt the carbs did you check the float hights? They can be quite critical on the NSR.

If the windings are starting to give up though that wont be helping one bit.
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If I have to take the carbs off once more...

I haven't rebuilt the carbs yet. Is it worth replacing the jets?

Is it worth putting in new float valves?

Depending what spec the bike is I would jet it to stock and check the float hights.

I wouldn't replace the float valves unless they show signs of wear. You'll have to see what they look like when you strip it all down.

Hey Rob, are you running on premix?

At current, my 18 is running on premix and I have the sam problem. If I drive in slow traffic for too long the one plug will die due to fouling. At the moment I'm trying to tame or solve the problem by running the idle mixture a little more lean than stock. This seems to be fixing me problem for now but I am still testing. I've literaly removed the airscrews and their springs and plugged the threaded hole it screws into with a short piece of blanked micro-irrigation pipe. The idea is that the system draws more air at low revs to keep things lean and hot. I've changed the size of the MJ's to 138 and 140 on "freeflow" air filters. The result so far is that I'm not having any fouling problems and the bike is running well with the bigger jets. I'm also showing a slight drop in petrol consumption.

Coming dow hills remember to run on compression only for short intermitent periods as I don't think it'll be a good idea to leave the crankcase un-oiled for longer periods. My mix is 40:1 so I'm sure theres enough oil in there to keep stuff slippy but Im just being safe.

Oh, does anyone have a pick of how the power-jet plumbing looks on a 18 R2J? The one in the tech section shows two solenoids for the PJ's but I only have one (one connector aswell so the other solenoid is definatly not missing somewere).

So your not running with any air screws at all and its still in the land of the living?
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If I have to take the carbs off once more...

Thats right Stephen. Its been like this now for 200KM's I checked the condition of things aprox 50km's ago. Had the barrels off to do some work on the powervalves and I couldnt find any marks of major scuffing or anything. Pistons look fine, as do their rings. Please note that the airscrews are out but the holes they screw into are closed. I suppose the right thing to do here would be to get a smaller SJ but my local dork dealer wants to scam me for far too much money. Besides, like I said, I'm just testing the setup now and I wont recomend it to any1 else unless they REALLY have to.

My powervalve servo controller is burned and I've manually positioned the servo half way. This gives me a good midrange but the power totally drops off at about 9000 - 9500 rpm. I feel this is ok since it limits the strain on the engine given its perculiar carb setup.

Sounds like some crazy ideas. I think the best idea is to wait for my bike mechanic mate to come down this weekend and get his big hammer out!

I'v gotten so pissed at the bike before for exactly this foul plug issue that I thought of driving it off a cliff and waving it goodbye! At this point I'm willing to try almost anything you see.