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Carb Vacume at Idle

Mikuni flatslides of the same size as stock?

But, I would start with valve clearance adjust, new plugs, ignition timing, and then try to figure out the carbs.
 
So, just wanted to update this post in case anyone else finds it useful. Upgraded the slides to 40's and the idles from a 48 to 42's and synced. What a huge difference! It's got some pep now, as I would expect, the mains I purchased were 5mm thread and I need 6mm, so just ordered the correct size in 135 and 140, to see which works better. I know the 125 is way too small with velocity stacks, as it won't go more than about 7000 rpm, it's starving for fuel! Once I get those in I'll post another update. Thank you to everyone for your suggestions. Here are some pics of the bike as she sits today.
 

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rdrguru said:
Has anyone ever seen a small flat washer on the idle jet of the carb? Mind you it is only on one side, the right cylinder carb had a washer, the left doesn't. None of the drawings show a washer there. I removed it and it is running great, so???
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On some there would be a fiber washer o-ring or both on the idle mix screw at the end of the spring. On the idle screw you place teh spring, then the washer followed by the o-ring ro keep everything in place and prevent air leaks. Check a DelOrto book.

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