Re: 86 750 Carb Trouble
Sorry to bump a pretty dead post. Took the bike in to a shop and they found a few key things wrong:
1) 2 of the carbs had missing / damaged retainer rings on the needles
2) carbs were quite out of sync
They resolved those issues, which got the carbs back in good tune. Bike idles great, runs great at low RPM etc. Now the only thing left to resolve is the WOT issue. They love the bike (guy who was working on it actually built this exact bike up back in the 80s), and spent quite a lot of extra time on it for me, trying to track it down. The things they did, along with the results:
1) Compression test - all results were above 160 and all about 160
2) leakdown test - less than 10% loss
3) checked all electronics
4) completely checked through carbs
4) jetted up and ran on dyno
5) jetted down and ran on dyno
Per the mechanic, it sounds like it's dropping 2 carbs at WOT (probably 3/4 -> WOT).
Next steps as far as I can tell are to check the valves, and probably pop the carbs off and check all of the values for the pilot air jet etc. I'm not sure what all they have changed over time (I know that it ran great consistently with the current setup).
If you guys have any advice I would greatly appreciate it!