Curse of the fuel pump?

[matt]

OK yet ANOTHER what's gone wrong question for you budding Honda engineers out there.

PROBLEM

Start bike, sounds buzzy at 5,000rpm and a bit gutless but don't have perfect AT to compare it too.

Ride around town sub 4k rpm seems OK. Temp 27-32C.

Out onto long straight, take it over 5-6k rpm and into 60-80mph for about 30seconds then all power goes, coast to a halt.

Will not restart but plenty of battery juice. Could turn over for about 30 secs non-stop.

Leave bike to cool for about 10mins, takes a few turns to restart and a bit rough when fires up but then OK.

Repeat riding style for fault to reoccur.

The fuel pump doesn't have a constant thud thud thud, more intermittent, though it does speed up with rpm. It also feels very hot, baked potato hot.

WHAT I HAVE DONE SO FAR
It has fuel in the tank!
No vacuum seems to be in the tank.
Checked battery connections and left on Optimate.
Checked all connections and fuses. (Bike very clean, only 14,000, never seen mud/rain)
Check fuel lines (not with tank off)
Replaced Rectifier and modified this with additional heatsink.

WHAT I WILL DO NEXT
Replace fuel pump.
Tank off for choke cable lube & check.
Airfilter check.
HT leads and plugs check.
Put carb cleaner through engine.

Diagnosis so far: Can't imagine it is electrical, otherwise low speed running would be faulty. It does seem to buzz a bit over 5k rpm, so maybe loose sparkplug but this would not cause it to cut out.

It now seems that at high rpm the fuel pump has to work harder, and then overheats and locks, this would explain all the symptoms.

Of course I am getting really mad with this because I am now unable to use the AT for fear of it breaking down as I cross the level crossing/busy M11 junction etc.

Anyone report similar problems and how they fixed it?

Thanks.

Desperate Matt

[Chad]

is there any improvement with a full tank of fuel check plugs, it dont sound like the choke cable . and the symtoms are very much like the fuel pump to be honest you should just fit the facet pump conversion for peace of mind when i had my @ i just did it even though the oe pump was fine

[djadams]

Probably best way to diagnose would be to temporarily bypass the pump.

1) Brim the tank (important to ensure there's enough fuel pressure to feed the carbs without the aid of the pump)
2) pull the electrical connector to the pump
3) disconnect the hose going to the pump, connect it to the hose coming from the pump.

Then, repeat your test ride to see if the problem goes away.

If it does, then you can ride it like that (so long as the fuel level is kept topped up) until the relpacement fuel pump rocks up...

If not, then time to explore other avenues.

[BobA]

Had similar symptoms on my RD03, and it was due to a bad earth.

Check the grounding points on the frame and the battery, and also check you are getting proper earths to things like coils and fuel pump.

This will cost you nothing but a couple of hours with a tester, before you start lobbing out on new parts

Good Luck

Bob

[mgillespie]

OK yet ANOTHER what's gone wrong question for you budding Honda engineers out there.

PROBLEM

Start bike, sounds buzzy at 5,000rpm and a bit gutless but don't have perfect AT to compare it too.

Ride around town sub 4k rpm seems OK. Temp 27-32C.

Out onto long straight, take it over 5-6k rpm and into 60-80mph for about 30seconds then all power goes, coast to a halt.

Will not restart but plenty of battery juice. Could turn over for about 30 secs non-stop.

Leave bike to cool for about 10mins, takes a few turns to restart and a bit rough when fires up but then OK.

Had a very mysterious problem on mine this evening, sounds almost identitcal to your symptoms.

I was going to take the @ upto a bike meet at West Bay, on the way out of town, on a longish straight, and i noticed it loosing power. I assumed it was time to switch to reserve (but a bit early), hoever, it did not help, and the bike eventually died. turning over did not start it.

I put the choke on full, and it would run, but not rev and promptly die. I could see petrol in the filter, so I knew there was supply from the tank. I removed the air filter, no improvement, I checked the spark on 1 cylinder, by removing the cap, it sparked like a good-un. I then turned the bike off, and went about getting the tools out, and weighing up my options.

However when I started it about 10 mins later, it ran perfectly (and in fact better than it has for ages). Went to WestBay, as planned, and the bike has MUCH more power than of recent!!!

Does this also sound like a pending Fuel Pump Failure???

[pinoy-al]

I have had this same problem on other bikes. I beleive that your coil is bad because that is the exact thing they do.
They will work well when they are cold but when they get hot they quit. That is the reason when you let it stand for awhile, it will cool down and work again.
I was told that they "break down" inside. What ever--- I just changed them and all was fine.

[matt]

Well this is what I have found and done so far:

Air filter was caked with black gunge - replaced.
Fuel filter was full of gum - replaced.
Fuel pump had copper dust inside solenoid cap and no contacts left - Facet pump fitted.
Solenoid off battery positive corroded - cleaned.
Frame earth and stock area corroded - cleaned.

Seems sorted so far.....but next on the list is:

choke cables lube/replace.
Coils replace.
Switch for single head lamp only