Welcome Aboard !

You'll want to...
• Run fresh high test namebrand fuel
• Strobe time the ignition at high RPM
• Check the diaphragms in the carbs for holes or rips
• Update to the latest carb floats and float needles
• Build one of these..... http://www.powerchutes.com/manometer.asp
...and balance the carbs at 1000 RPM with the Idle Screws, and again at 1800 RPM using the cable adjusters

Then Look Right Here to see if there's anything else you need.

Hope this helps.

Thanks for the response Wobbly. I did attach a Carbtune (Manometer) again today and discovered I needed to do quite a bit more tweaking of the throttle screws to get the vacuum balanced, but once I did she is much smoother and I no longer have the flat spot at around 4000 rpm. Mixtures are a little rich for now (about 13/4 to 2 turns). I forgot to mention in first post that I measured primary and secondary resistance of the original coils and they were both a little below spec in the Clymer manual. I have an aftermarket Dyna coil I plan to install next and see how that affects the performance as well. Thanks again for the reply!

Thanks for the response Wobbly. I did attach a Carbtune (manometer) again today and discovered I needed to do quite a bit more tweaking of the throttle screws to get the vacuum balanced, but once I did she is much smoother and I no longer have the flat spot at around 4000 rpm. Mixtures are a little rich for now (about 1-3/4 to 2 turns).

Thoughts...
• By "throttle screws" I assume you mean the Idle Speed Screws.
• Adjusting the Idle Speed Screws will have zero effect on 4000 RPM. That's what the cable adjustment is about. You made no mention of that. Was that done ?
• Sorry, but the Idle Mixture Screws have almost zero effect on running "a little rich for now". And how was that determined, anyway ?

I forgot to mention in first post that I measured primary and secondary resistance of the original coils and they were both a little below spec in the Clymer manual. I have an aftermarket Dyna coil I plan to install next and see how that affects the performance as well. Thanks again for the reply!

Thoughts...
• I was always taught that if it ain't broke, then don't fix it.
• So you believe a 3rd party manual in place of an OEM part ? You are free to believe what you want, I'm simply interested in the thought process that got you there. Why would you want to make dramatic changes to an engine that seems to be responding to standard tuning techniques ?
• The measurable effects of a Dyna coil are going to be negligible. Metrics are only going to be gathered in 1/4 mile times and overall fuel mileage. The R65 is not a 1/4 mile bike. And since the carbs are still in a state of being washed out after long non-use, fuel mileage is going to be radically changing even if you do nothing. So I'm curious as to this "plan".
• And the plan is to swap the coil without replacing the 40 year old wires and plug caps ? The wires and plug caps are known problem areas due to aging. I'm again just curious.
• I note that setting the ignition timing was in the list of suggestions. No mention of that was made in the reply, and yet it's probably the one thing that holds the most control over engine smoothness, throttle response, and fuel mileage. Just sort of seems like factor #1 is being ignored in favor of factor #87. Again, it's your machine, I'm only interested in the thought process.

Glad it's running better. All the best.

Geez Wobbly, easy does it!
Yes, I meant idle screws not throttle screws.
Regarding running rich, I can actually smell a change after enrichening the mixture, plus I get a few pops from the exhaust when closing the throttle from higher RPM from unburned fuel.
I did switch to an aftermarket Dyna coil which seemed to help it run a little smoother.
Regarding the timing, I did say I checked it in my original post. I spent a LOT of time getting this right including checking the static and dynamic timing.

Contrary to my own intuition, I’ve been led to believe that popping on deceleration with a closed throttle was likely due to the IDLE mixture being set a bit LEAN. Of course this would have no effect above idle speed. True?

Thanks for your comment Cubdriver. In my previous experience with Honda carbs/motorcycles rich mixtures could cause popping on deceleration, although those carbs had a special diaphragm control device which was there to stop flow of fuel in closed throttle conditions on deceleration. Our carbs are different though of course. After reading some posts regarding the "EGR" (pulse air injection) system on the early 80's bikes, I may remove or disable mine to see if it affects performance as many have done.

There are numerous reasons why an engine might pop on deceleration. One big reason is oxygen entering the fuel rich exhaust. So it stands to reason that your EGR might be the cause of the popping and NOT the carb settings.

There are numerous reasons why an engine might pop on deceleration. One big reason is oxygen entering the fuel rich exhaust. So it stands to reason that your EGR might be the cause of the popping and NOT the carb settings.

Thanks Wobbly, I was thinking the same thing. Several times during my adjusting of the carbs, I would point a heat gun at the top of the exhaust nut just to get an idea if both sides were at about the same temperature. They were not. The right side was consistently 50-70 degrees hotter. I don't know how significant that difference is, but I did immediately suspect the EGR system since it can provide ambient air right at the exhaust port area. I am going to remove it soon and will report back anything noteworthy.