Last year I bought a '92 F2, and it was in rough shape. It ran, but barely. Among it's latest developments of never ending issues, it has decided that between 9-10k rpm, I'm going to go absolutely nowhere. As soon as it hits 9k, it loses all power, and slowly crawls from 9k to 10k, and it makes no difference if the throttle is at 1/2, 3/4, or full. It's slower than trying to take off in third gear..

This issue developed after I had noticed it began to stutter, and generally run rough around 4.5k-6k, sounded like it was bogging down slightly. I noticed some holes in the exhaust so I patched them with some aluminum 3M tape (a little ghetto, I know) just to see if the exhaust leak was causing the issues. That made the bogging issue slightly better. The throttle is giving a much snappier response all the way up to 9k, where again it just loses power. After it hits 10k or so, power comes back mostly and I can rip it up to redline, slower than before the issue, but definitely not terrible.

Anyone have any ideas what could be causing this? If it helps, it's got a manual CCT and I hear a slight whistling/gurgling noise at idle when I blip the throttle.

Thanks in advance for any help!

 

Has to be a carb issue. The exhaust may have made things worse, but its still a carb issue overall. I'd take them apart, clean and sync them.

 

How hard is that for a newbie to working on engines? Most I've done yet is replacing the stator.

 

Well, if you've never messed with motorcycle carbs, its a bit of a pain in the rear. But on the F2 is pretty straight forward. Pull the seat, then loosen the tank, unhook fuel line and vacuum line from petcock. Remove tank, then air box lid, filter, velocity stacks, then the bottom of the airbox. Loosen the clamps that connect the carbs to the engine, I loosen the clamps on the engine side of the manifolds (the black rubber tubes between the carbs and engine). Now the hard part, push down, pull up, on the carbs over and over and finally they'll come loose. If they have never been off or havent been for a long time, its going to be a struggle. Get your rags ready. Once they're off lay a big towel where the carbs once were to soak up the gasoline that going to drain out while your flipping them all over the place trying to get the cables unhooked. You could drain the bowls before hand if you want. And Im sure I left little things out like crankcase breather tube hooked to the air box and the carb breather tube that goes to the little square filter thingy. Most important thing after carbs pop off the engine is cover the intake ports with duct tape or something so not to drop anything in your engine. I stuff paper towel in my velocity stacks as soon as I get the filter out, just to be safe and again when the carbs come off, in the intake ports. Also label your cables when you get them off, that way you get them back where they go. As far as dismantleing the carbs, Im tired of typeing so go to a "carb sticky" in the F2 or F3 section. Good Luck.

 

Listen, there's only one way to learn how to do it - by doing it!

So, pull the carbs, make sure you don't drop anything into the ports, and then follow the sticky in the F2 section.

You can make a sync tool for a couple of bucks, too - Google is your friend. And everything else can be worked on with a long screwdriver and a couple of wrenches.

What's also cool, is if you get comfortable with these carbs (don't worry, you will), you'll essentially know how to work on any CV carbs. You'll just need some specs.