xeris

Maybe at steady throttle the mixture is good, but when down shifting and whacking the throttle open the slide does not lift quick enough (because of the blocked lift hole) and there is a momentary lean condition.

twist

The HRC type slide is also the cure for the Dr. Honda stacks which cause the over rich mid-range. The problem here is the stacks create too good of a vacuum signal to the slides causing them to open to quickly. So in this case you would plug one hole in each slide. This will eliminate the rich condition without causing a lean condition on the top end.

I'm running the billet stacks so following hawks suggestions, the stacks pull more vacuum so I need to slow the slides down. More air coming into the carbs would produce a lean condition, no?

NZSpokes

Agree 100%

But if its when you wack it open from a steady cruze i would suspect low needles over the slide opening to slow. Idle will have almost no play in this area.

xeris

Yes, that is how I understand Hawks write-up. Maybe all you need is to adjust the shims a bit. Hawk states that his numbers are only a starting point.
I dream of FI.

twist

I have adjusted the shims on the front carburetor needle, was .35 adjusted to .40. front and rear carbs are the same now, test drive today.

AndyMX47

Have you tried the slides with two lift holes in them?

I do not have the billet intake stacks, but had a slight hesitation when you whacked the throttle open, and actually ended up putting the extra lift hole back in my slides. The bike takes off like being shot from a cannon now.

A dyno run showed I was momentarily going lean - even though my shimmed needles had me running rich at cruising rpm. Opening up a lift hole in the slide eliminated the hesitation. Holes are free and can be plugged...and you don't have to remove the carbs altogether to get the slides out.

If you can start the bike and idle cold with no choke, you're idle settings are likely too rich as well. Use the idle drop procedure to set the fuel screws, and see what that tells you - you should probably turn them in a bit.

twist

so here is what I've found with the carb tuning.....
I added shims front and rear, just under .04 front and just over .04 for rear.

I discovered the choke cable for the rear carb was under the slide dome so kinda sticking I think. I moved the cable so it is over the dome and it moves much better, no longer sticking.

By complete coincidence I discovered an exhaust leak on the left side muffler, (2 bros carbon cans, sleeves are riveted to assembly that connects to exhaust header) The leak was coming from where the sleeve is riveted. That has been fixed along with a new exhaust gasket on the right side header to muffler.

The irritating hesitation is gone and the bike runs great! Problem is, I think it can be better. I discovered a shop that rents out space to work on bikes, they have all the tools and a fantastic facility with lifts to work on bikes only. Moto Shop ? A do-it-yourself motorcycle shop located in San Francisco offering classes and space to fix your own moto. Cheap too, $15.00 hr during the weekend and $10.00 during the week. So I now have a better place to work on the hawk than I had when we had our house. I'm lovin life!!

AndyMX47

when you test ride it try to find the difference between rolling the throttle on, and whacking it open. Rolling it on producing a stumble tends to indicate needle height issues, whacking it wide open tends to indicate slide speed issues.

The lift holes have nothing to do with your mixture when cruising (the slides aren't moving up and down then), just how quickly the slides react to changes in vacuum.

It's tricky juggling needle shim vs. slide speed. I had the same issue, and made it "better" by shimming my needles more - then found out I was too rich at cruise (too much shim - .040" or so front, .06" or so rear) when running on a dyno with and A/F measurement, and spiked too lean when the throttle was whacked wide open.

I found a local dyno guy to help me out for $60 - it sure made it a lot faster to find out what was going on.

Turned out to be a little too much shim with too slow lift speed.