I very well could be, it is unusual to have a pump prime on a carbed bike as there is fuel in the float bowls so can start and run without a pump (even just gravity fed) unlike an injected bike needing the pump to generate the pressure and fuel flow. Could possibly have been over engineering from Mr Honda

 

Ohh, needs a bit of TLC that one...

 

the only reason for the pump is to keep the bowls filled under higher RPM's. the only issue is that it can become a restriction if it fails. I thought it was odd to have a fuel pump on a carbed bike too until I put thought in it, and now it makes a lot of sense. now, lets say you pull your carbs off to clean them and when you reassemble everything, the bowls are empty. would it be easier to have a fuel pump prime at key-on? or would you rather rely on gravity to try and push fuel through the pump to fill the bowls? I would think that from a reliability stand-point, the prime at key-on just makes sense.

 

I personally don’t see point of pump for carby bikes. Previous generations didn’t have one. I’ve converted my F4s and VFRs to gravity-feed without any problems.

Prime on start is variable too. If bowls are filled from previous ride, pump might not even move full-stroke before turning off, so you won’t hear anything. After carb pull, yeah you won’t have anything in float bowls, so pump may run for second or 2 to fill bowls.

You can do final functional test of pump:

1. Disconnect hose from carbs and aim into measuring cup
2. Key ON, start/stop=RUN
3. Press START for 10s

How much petrol did pump flow?

 

I will do a pump test tomorrow,

Just out of interest to convert to gravity im guessing i would just bypass the fuel pump.
Tank - fuel filter - carbs ?

also assuming that then if the fuel relays were at fault it wouldn't mater as the fuel pump wouldn't be needed

 

yeah, just leave pump & relay as is.

Trick to converting to gravity-feed is to shorten hoses as much as possible. And keep hose-run as vertical as possible without any downward loops where fuel has to go uphill to reach carbs.

Here’s an example. Short with no down/up sections. Maybe just 5” of hose between petcock to carbs.

 

thank you i might have a look at doing this, did you unplug the power connector on the pump to stop it trying to run ?

 

Yeah, just unplug pump and relays.

 

My '99 does that also!