Losing power, I think it is a fuel problem

[HarryL]

If I run fairly hard throttle up to around 6,500 rpm in any two gears, I start losing power. I can then back off the throttle and get full power back after about 20 seconds. The bike otherwise starts and runs fine. This started a couple of days ago. I have 125k on the bike but only 10k on the fuel filter and carb rebuild.
I pulled the fuel pump tonight and the filter is not clogged and the pump seems to be working OK when I started the bike back up. ( there was enough fuel in the carbs to start the motor for this test ).
I had about five gallons in the tank that I drained through the hose that supplies fuel to the filter and it took forever as it flowed very slowly, which makes me think that there may be a restriction in the tank.
Is there a screen in the tank that may be clogged and is there a pressure/flow test that I can do on the fuel pump?

I have read that the fuel pump has a set of points that can fail. The pump looks sealed, is there a way to get to the points without ruining the pump?

Thanks in advance for any and all help

HarryL

[voyager55]

https://amervoyassoc.org/techtipsXII2.p ... Pump_Point" onclick="window.open(this.href);return false;

[ekap1200]

Hello from Nj. take a close look at the 90 deg tube at the bottom of the fuel tank. also make sure you have the correct hose from the tank and not an automotive line. the OEM hose is two different sizes making a nice fit. auto hose requires a hose clamp. there have been times I have seen that 90 deg tube bent to less than 90 and causing restrictions.
to listen to the fuel pump work. just remove the two wire connection on your starter relay. ( left side , ahead of the 3 relay pack ) then key-on , start button pressed , you will activate the pump. having the carb drains open to a clean container you can observe the fuel flow.
Look at that fitting first.
Gene

[triton28]

Along with Ekap's suggestion which may well be the problem, try opening the filler cap 1/4 turn on the gas tank and then trying your problem rpm range. Make sure you don't have a high level of gas in the tank or it could splash or spill out while riding.
If the problem goes away then the tank is holding a vacuum when the filler cap is tightened, which possibly means the rubber tube from the fuel tank spill cup is blocked. Or the white plastic tank breather assembly, attached to the cup and forming part of the hose from the cup back into the tank, is blocked.
If the problem still persists and you have checked the feed line to the filter/pump as per Ekap's post, then I would look at float levels.
In so far as the fuel pump points, they either work or don't work so I wouldn't look at that area.
Just a thought,
Dave

[HarryL]

Problem solved. The hose from the tank to the fuel pump was cracked at the fuel filter inlet which caused the pump to suck air and cavitate. It is the original hose, wasn't crimped, and actually didn't look bad, except where it was cracked. I cut off the bad spot and put it back together.

I appreciate all of the advice, which allowed me to run the pump and troubleshoot without having to start the engine.

Thanks again

Harry