Slow acceleration on 1996

Hi all, pretty new here, been lurking and searching for a while.

I have a 1996 VFR that has been sitting for a couple years. After cleaning the carbs and replacing the spark plugs, the bike is running, and rides like a dream, so long as I don't get enthusiastic with it. Getting onto the highway is a bit of a chore, too.

What is happening is this:

When the bike is fully warmed up, choke off in neutral, the bike will rev freely as expected. Starting off from a stop, it seems to run OK at low revvs, but once you start to climb in the revvs, it is *slow*. It will eventually get to redline, but it takes forever. Like 20 seconds forever. Does not matter if I slowly roll on, or grab a handful of throttle. Slow. Same condition in all gears.

Also to note: when I do quickly open the throttle, there is an initial surge in power that immediately disappears and continues in slowness. The surge does not come and go.

Now, I'm new to carbs (always had EFI on my other bikes). I'm thinking I may have not totally cleaned something. Based on research it seems that the bike is getting a lean condition with the throttle on. This leads me to believe it isn't getting fuel. So, something is clogged.

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My questions:

1) The needle jet holder (part #15 on page 6-18 of the service manual) was pulled and cleaned. All the tiny holes down the side were cleared out. However, I noticed that I couldn't see down the bore of it. I cleaned it best I could, but I'm not sure I got it hollow. Should it be? And if so, is the bore constant end to end, or is that hole smaller?

2) Could this also be caused by a clogged float valve?

The pilot screw remains in stock position as I don't have the D shaped tool. Bike also needs a sync, but that is for later when I get a tool.

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What has been done since bringing it out of storage:

-New battery
-New oil and filter
-New spark plugs, properly gapped
-Pulled the carbs to clean them
-I pulled all the jets to clean them. In the process I broke a slow jet and so I replaced all 4. All jetting is stock.
-Checked fuel pump, it works well.

The bike does have a slipon Two Brothers exhaust, but I do have the stock pipe and the problem persists with that pipe.

​​Thanks in advance for any help, sorry for the long post.

Matt.

 

It's really easy to get the slide diaphragm installed wrong if you've had the caps off. Test by blowing air into the large air vent hole to see if all slides rise.

Main jet holder tube must be clear. If you cant see through it, the main jet may be clogged, although that is very rare.

When you get the adjusting tool, it usually helps to open the idle mixture screws 1/2 turn or a bit more as the jetting is set lean to meet EPA standards.

 

Slides all move, and together, so quite confident the diaphragms are OK.

Hmm main jet holder may be it. Do you recall if the holder has a constant inner diameter? IE: 1mm end to end? I'm thinking the hole was smaller, but maybe it is clogged buildup...

 

remove main jet from holder and put a wire through the tube. tube is constant in diameter.

 

Well, pulled it all apart, gave everything a good cleaning. Main holders looked clear when I pulled them, but still gave them and all else another go-over.

Bike is now running great!

Thanks for your help!