Best jetting for stock carb and M4 exhaust?

[baroquenride]

I did a search on this and didn't seem to find what I'm looking for so I'll ask. I've been riding my Baghira around town and out on country roads for a couple hundred km's and the carb seemed fine. Today however, I did about 160km with most of that at freeway speeds of 65-75mph. Although it was a little windy, I began noticing slight stumbling/hesitation after awhile while using steady/constant throttle. It was mostly annoying but I did have a couple backfires. After half of the ride was done I realized that I could add some choke and used the 1st notch on the choke to add fuel, which eliminated the hesitation, but it seemed nice at the 2nd notch as well- perhaps better. This tells me I'm a little lean on the main jet or the needle position isn't ideal and as far as I can tell I've got stock carbs, with stock configuration, with the M4 exhaust.
Here are the specs: L- Main=130 R- Main=165 L-needle slot=4 from top, R-needle slot=2 from top
So should I move the clips to a different setting, or do folks go bigger on the main jet size?

I found this thread which kinda helps: viewtopic.php?f=3&t=1157&p=7474&hilit=needle+position#p7474 and makes me think I should move the needle on the R side to the middle position?

[baroquenride]

So everyone is using the stock needle height?!?

[baroquenride]

I went to swap the circlip on the needle and holy cow that carb is buried in the frame. It appears this will be an all day job to simply gain access to the needle jet. While I can access 3 of the 4 screws on the top of the slide, the 4th is buried under the downtube with a 1/2" to spare and I have no idea how to access it (not enough room to put a screwdriver, or turn a small vise-grip clamped on the screw) so I'm not going to do it any time soon and will just run the bike with the choke slightly engaged.

[baroquenride]

That might be why the carb was never cleaned?

You're assuming alot. This bike only has 4500km. Hardly any miles and almost stock.

[breakwellmz]

I did a search on this and didn't seem to find what I'm looking for so I'll ask. I've been riding my Baghira around town and out on country roads for a couple hundred km's and the carb seemed fine. Today however, I did about 160km with most of that at freeway speeds of 65-75mph. Although it was a little windy, I began noticing slight stumbling/hesitation after awhile while using steady/constant throttle. It was mostly annoying but I did have a couple backfires. After half of the ride was done I realized that I could add some choke and used the 1st notch on the choke to add fuel, which eliminated the hesitation, but it seemed nice at the 2nd notch as well- perhaps better. This tells me I'm a little lean on the main jet or the needle position isn't ideal and as far as I can tell I've got stock carbs, with stock configuration, with the M4 exhaust.
Here are the specs: L- Main=130 R- Main=165 L-needle slot=4 from top, R-needle slot=2 from top
So should I move the clips to a different setting, or do folks go bigger on the main jet size?

I found this thread which kinda helps: viewtopic.php?f=3&t=1157&p=7474&hilit=needle+position#p7474 and makes me think I should move the needle on the R side to the middle position?

When i had the standard carb on my Mastiff (same carbs as yours) i seem to remember making those needle recommendations. With the M4 exhaust fitted that advise would be even more relevant as would larger main jets. Do some searching for Bill Jurgensons jetting suggestions on here or on the FB page - https://www.facebook.com/groups/MZSkorpion
The standard pilot is too small as well.
Check out the hidden filter under the float needle whilst you have the carbs off.
Good luck with it.