Eric,

I am VERY grateful to get your feedback.

You are correct- I need to sit back for a moment, re-set and think what I've been doing. This fault findng process is a little exasperated by long gaps of work travel in between where some of the finer details of what I've done fall between the cracks.

I was very excited that I found the choke issue and really thought that was the issue.

So to address your initial reply.

I rebuilt the engine myself- with rebuilt cranks and all new OEM seals but I'm no expert so there's always the thought I may have made a catastrophic mistake along the way- however I am fairly confident the integrity of the engine is good because I very carefully performed a leakdown test and the results were the best I've ever achieved on an engine. Can't remember the exact numbers but it held pressure for a long time. In addition- I've just been an assembler in this process, the engineering such as crank rebuild and cylinder replating were done by experts....

I did a compression check just to make sure nothing mechanically had happened since I got it running such as a holed piston or cracked ring or something. The exhaust bridges have been mended and I was just wondering if maybe that repair had failed and in some way was affecting the compression. Both cylinders had identical PSI so that's good.

Anyway...as to which cylinder is the problematic one- it's always been the front. I think I was confused by the twisting and turning of the TYGA expansion chambers.

Thanks to your advice I think I have a new path which is...

1- The bike was performing quite well when the RC Valve controller was in Japan getting fixed. That was when I think I talked about it having a very narrow power band, and yes it was before I discovered the choke issue. I read somewhere that not firing after 4000 rpm could be a sign of the valves be maladjusted so I might try running the bike with them disconnected and held in place - and if both pull cylinders pull all the way to the redline then that will be interesting.

2- Love the idea of connecting a strobe and seeing if it still flashes all the way up the rev counter.

3- Will try switching the coils and see if the the fault follows the coil.

4-Will swap out the plug caps for new ones, actually, I have some brand new NGK red ones on my RZ500 which is sidelined with bad crankseals so I'll probably rob them. Been using the BR9ECM plugs for sure.

Thanks again for the time you spent thinking about this!!