bogging down

[Drewski]

Hey all. '98 SuperHawk with 23K on it and in the past month or so just started bogging down between 3 and 4K RPMs. I recently changed out the stock gas cap for a Vortex cap but didn't notice the issue at the time of the change. The only other thing I did that was out of the ordinary was add Stabil to the fuel. I did change out the diaphragm in the petcock in the Spring for a similar issue, but it seems a bit off that I might have a tear in another diaphragm after only 1 season. Any other ideas on why the bogging might only be limited to the 3-4K RPM range, otherwise, she runs strong. Thanks in advance for any ideas on what to look for.

[butcher bergs]

When is the last time the intakes were sync'ed?

[Woodsy]

does it get better as it warms up? Superhawks hate the cold and you will feel hesitation in weather like this initially. If not than i would say it is a partially clogged jet in the carb or, like stated earlier, mis-sync.

[Drewski]

I've had it for about 10K miles and haven't had it sync'ed in that time, this just popped up out of nowhere. Thanks for the suggestion on where to look. It just seems weird that it would only be acting up in this RPM range.

[butcher bergs]

I've had it for about 10K miles and haven't had it sync'ed in that time, this just popped up out of nowhere. Thanks for the suggestion on where to look. It just seems weird that it would only be acting up in this RPM range.

Maybe check the diphragm again. I have seen petcocks get sticky if they aren't semi-regularly used.

In the event that the bike sat for any amount of time, Woody's suggestion on looking at a clogged jet issue would be the first thing.

If the carbs aren't balanced, there can be a stumble anywhere in the engine RPM. Even though it won't hurt anything if left alone, the characteristics will change with time and miles meaning that, what is noticeable at 3-4k now might change to another RPM range as miles are put on.

With 23,000 on it, if it's never been done then it's probably a good idea to consider it anyway.

[LuvDog]

Check the jets... when I've had problems with bogging down mid rpm that was the problem.

[Drewski]

Thanks guys. It will be a Spring project for sure. I took it out again today and lost all power. I had to limp it home the last mile in 1st gear. At least you all gave me a few things to start with.

[jasnmar]

Lost all power...

Unlikely a carb sync issue.
Probably not jets.

Check the coils. See if you have good spark before anything else.

It very well may be a fuel issue... Eliminate a spark issue first. Simple to check.