Loss of power at 40 mph

I just finished tuning the carbs ( wet set floats, cleaned, synched) and I thought everything was ok but.... I was riding today and it was driving like a dream and after about 15 miles I lost power and it seemed to bog down. when I rolled the throttle it still had some power and the exhaust seemed louder than usual, but if I laid off the throttle and squeezed in the clutch it died. I started it back up and drove about .5 miles and it regained full power and it seemed to run ok after that.

Any ideas of what could have caused this power loss. I think it's running just right. I pulled the plugs and they seem to be light tan.

 

Sounds like there was a small obstruction somewhere in the fuel and you pushed it out.

 

Check your vacuum line going to petcock - make sure it is a good line and firmly secured. Have you checked your fuel flow from the petcock? Sounds like a fuel delivery issue of some sort.

Did you have an inline fuel filter? If not, do so to prevent any small debris from mucking up your fresh carbs. If so, how old is it? Ensure that fuel is freely flowing through that too.

 

Lanker I do not have a inline fuel filter. Any advice on what type I should get? Would just a regular lawnmower one work? or do I need a special one?
thanks,

 

Could be a vacuum in the tank as well. If it happens again, open the tank and listen for a quick sucking of air.

The tank cap has an air vent.

 

Buy a FRAM Universal Inline Filter.

Don't by one NOT "Made in the USA"

Imports can be troublesome.
I bought an Import when AutoZone was out of FRAM's'.
The paper filter was more of a Plug than Filter.

 

There's not a whole lot of room on the 550s so I prefer the "straight-through" type.

You DO need to replace them regularly though: http://xjbikes.com/Forums/viewtopic/t=34020.html

Here's the only pic I really have of one installed, and this was before I had the rack off to set the floats and install black carb hats, at which time I trimmed the portion of fuel line at the bottom so the filter sits more "downhill" than in this pic:

 

your #1 intake boot looks like it is cracking pretty good.....

 

"Looks like" being the key phrase...

That's an old pic (pre remedying) but none of the cracks went all the way through. I flushed them and packed them with black adhesive high-temp RTV and they're fine (and that was 10K miles ago.)

 

So if I do hear a sucking sound does that meen I need a new cap or can I just get new rubber for the cap

Thanks for the tip on the filter. I will drop by oriellies or autozone and grab a fram. I know what you mean though. I only put fram filters on my vehicles transmissions, fuel and oil.

 

gas cap rebuild

The link above includes references to chacal's inventory on a lot of the parts used. I haven't had the luxury or need to disassemble a gas tank cap, so I don't have any further experience to share.

btw: it may be a good reference site for you to "bookmark" in your Internet browser... www.xj4ever.com