@automan I have this motor installed in a 74 DT360 chassis, using the DT speedo and tach.

This seems like a case where taller gearing helps acceleration. Stock was 14/51 I believe. This one is running 17/44. Doesn't run out of top end until about 95, and the first few gears are tall enough to put some power down without just smoking the knobs off the tire.

@RT325 I am always surprised to read reviews like that. I've got about 550 miles on this thing so far, no problems with scuffing or seizure. Piston seems to be hanging in there just fine. Noise is not excessive and is not increasing.

Seems like a pretty good design for the era, with some minor issues resolved its been solid. I'll put up with some quirks for a 500cc two stroke, that powerband makes it pretty easy to overlook things.

Whew doggy LSR bike indeed!

I had to go look see what i said.
Ah, the Cycle Road Test!!.
Great job getting yours to run the way you want it.

Turbodan talked to Lunati today he said he knows that he has extra cylinder and other parts plus the complete bike maybe sell it for 3 to 4 hundred dollars it’s in there shop in Mississippi about 30 min from me. I’m pretty sure he will give me the cylinder 

Joey told me today his Dad has a toggle switch on the handlebar and he remembers he could flip the switch and it would retard the timing so it would be easier to start. Is that even possible?

Anything is possible. With the standard decompressor and Rex's ignition it starts pretty easy though.

It will be interesting to see what he's got. A spare top end would be cool. I like having a spare.

I vaguely remember there was a service bulletin for the SC500 where you could modify the CDI wiring for easier starting.  I don't remember a switch...  it was more like adding a capacitor into one of the CDI wires which would retard timing at low rpm.  I suppose you could do the mod with a switch to go back and forth?

I vaguely remember reading a magazine article where they switched out the 500's complete ignition
system for an MX 360 system . They were very impressed with the results ,
which gave the 500 a much nicer power delivery .
I can't remember which magazine it was now .

This should be here next week. This is pictured test fitted on a 360. When it arrives I'll hope to get it on the 500. All dimensions with the exception of exhaust head pipe diameter appear to be the same. With luck it fits right up.

Estimated power and torque as predicted by the software used to model the pipe is in the neighborhood of 43 hp and 39 ft-lbs at the rear wheel.