Power loss

[Youngsmoke]

Hey all,
  Hoping you can help me with a problem.  I took a little trip with the wife down to laughlin this weekend (from vegas) and noticed that on the way out there I was losing power in fifth gear.  To be fair, we were doing some hills and there is an elevation difference of about 4000 feet, but even with the throttle wide the RPMs and speed were dropping, and i didn't feel a response.  Could the elevation difference be the culprit?  if so why were the RPMs dropping?  the other thing that confused me is that I was riding around mount charleston last week which has an elevation of about 7500 feet and didn't notice any loss of power.  The obvious difference between the 2 rides is charleston was just me and laughlin was 2 up but is there something else that I am missing?
thanks for your help

[sandy]

You don't say the age or miles on the bike. But it's common for the petcock to reduce flow if the diaphragm is going out. Also the vacuum lines can be old and if the petcock's line to #6 intake is bad, higher throttle settings can reduce manifold vacuum which will cause the petcock to shut off till the rpm's reduce.

[Youngsmoke]

Sorry, totally forgot.  it is a 98 tourer with just shy of 50k miles.   I just bought the bike about a month ago and have been going through and giving it a tune up.  changed oil and filter, air filter, adjusted the valves, about to change the rear drive oil.  
  when I took the tank off to change the air filter I did take apart the petcock to clean the screen, which i saw mentioned in the shop talk section, and found that the screen was gone, but the other parts were there and clean.  i thought it was weird but didn't know what to do about it. thoughts?  I also did change the plugs and when I did it seems that the #5 cylinder is running rich.  i was thinking that i might need to sync the carbs to fix this, though the previous owner said (and i talked to the shop who confirmed) that he had had that done just last year.
  also forgot to mention that it is a cali model bike, and does not seem to have been desmogged.  is this necessary?
  Last thought, what do you consider "higher throttle settings"? because I was cruising at around 65mph in 5th at around 3k rpm when the loss of both power and rpm occured.  even wide open i couldn't get the engine past like 3200rpms in 5th.  it would rev when i dropped to 4th though.

[sugerbear]

did you change the type(brand) of gas you put in. change stations?

[Valker]

Anytime the tank is taken off, always suspect the vent line being slightly kinked upon reinstalling it.

[jammer]

U said upon tank removal there was no filter.  Did U check the tank? The plastic filter   often remains in the tank when U remove the petcock assy.

G

[BOZ]

1.) When you had the petcock out, did you take it apart to inspect the internal diaphram?
2.) You said there was no screen on the petcock tube. What can happen is that the screen sometimes remains in the tank rather than staying attached to the tube on the petcock. Did you check inside the tank to look for the screen?
3.) From what you've said, I'm guessing you have a vacuum line leaking or a petcock that needs to be rebuilt.

Good luck with it.

[Youngsmoke]

i guess i don't understand where this screen is, i assumed that it would be in front of the diaphragm.  how big is it that it is staying with the tank?  also when i am inspecting the diaphragm, what am i looking for?  just cuts and tears?
thanks all

[lee]

I suggest you go to HDL parts sight.  Go to the OEM parts, look under Fuel Tank.
This will show the petcock and SCREEN (#4).  The screen usually stays in the
tank when you pull the petcock off.
As for inspecting the petcock,  IMO it does more harm than good to take it apart
and not install a new cover set.  Just pull a vacuum on the petcock and if it leaks
off in 3 or 4 seconds or less then its bad and the cover set needs replacing.

[lee]

http://www.hdlparts.com/fiche_section_detail.asp?section=148816&category=Motorcycles&make=Honda&year=1998&fveh=3477