So rebuilt carbs, new jet kit. This was happening before I did that but just a bit of insight so I know it's not the jets clogged or similar.

I've tried different mixture settings (2 out from bottom, 3 out from bottom, 2.5 out from bottom) and it changes the effect but only slightly.

Basically, when I just blip the throttle, the RPMs will rise to around 4K and SLOWLY come back down. If I'm riding and I shift into gear, I can force them back down with the gear but at idle this is what happens. The ride isn't terrible, it is a bit rough as far as the engine feels "skiddish". It feels like very slight stuttering every now and then.

I made sure good seals were on both ends of the carb boots so I don't think that would be the issue. Any recommendations? Here are pictures of my plug and also a video of what's happening.

https://drive.google.com/folderview?id=0B5G4y-tb-IZcV2I0LWFIYWc2Nms&usp=sharing

Short and sweet, it sounds like either too much air or not enough fuel. Do you have an inline fuel filter? That can cause fuel flow issues. If not, I'd recheck the vacuum lines. You may have one exposed.

Also, is it completely stock? Your setup (exhaust, air filter, jet sizes) might be useful.

Everything is stock. The new jets are stock. I do have a fuel filter, but this was added when I rebuilt the carbs and this issue was occurring before I rebuilt the carbs.

So... I have a vacuum line connected to the petcock that goes to the left carb. The other carb vacuum inlet has nothing connected to it and doesn't have a cap on it. I was under the impression that this was closed internally. (I'm not talking about the ports on the top of the carbs but rather the side, the port that, on the left carb, connects to the petcock.

Should this be plugged/capped?

Well, I just went outside and held my finger over that exposed vacuum inlet on the right carb while I blipped the throttle and nothing changed, so I can't see the being the issue.

what do you mean by jet kit?  original Mikuni jets or Dynojet crap

~~~ Paging Mr Buddha ... Mr Buddha report to the thread please!? .. ~~~ 

Sorry if I wasn't clear. The jets are part of a carb rebuild kit I got online.

Like I said before, this problem was happening before I put new jets in so I know that the jets are not the issue.

Have you tried adjusting the idle adjust knob?  that can result in similar issues

Quote from: pixlgeek on April 10, 2014, 08:26:39 AM
Sorry if I wasn't clear. The jets are part of a carb rebuild kit I got online.

Like I said before, this problem was happening before I put new jets in so I know that the jets are not the issue.

They could still be a contributing factor.  Either due to different geometry of non Mikuni jets or being a somewhat different size.

What I'm reading, this sounds like symptoms of carbs that are out of sync?

That could be the case. Pull the plus and check for color differences. They should both be a nice brown color. If there is a variation between the two, it most likely is a sync issue.

And don't forget to post pics!

There are pics and a video in the link in the original post. thanks

Whoops. Definitely skipped that lol. The plugs (assuming that's both of them) look a bit lean to me, but the bike runs lean from the factory. So with stock settings, that's expected. However, I'm still thinking there's a vacuum leak somewhere, or the fuel isn't quite making it to the carbs properly.

It's a long shot, but if the vacuum lines are fine, try removing the fuel filter. The jets may have been clogged beforehand, causing the issue. Now it could be the filter. If it's not the filter, it could be the tank vents? Easy way to check that is by putting the petchicken on prime, as it bypasses the fuel vacuum. Actually, I'd try prime first. It's easier lol.

Syncing the carbs is always a good idea

When were the valves last checked? Tight exhaust valves can also cause hanging idles