Africa twin run around

[ratty]

Help !! I´ve been following many of the threads on similar problems and hoped that I had already sorted out my 1989 africa twin 650 problems. But no.
One cylinder cuts out with the rpm counter then two minutes later the bike grinds to a halt. A few minutes later it re starts on a single cylinder then the second kicks in before it dies again. Some fuel still in the tank.
So due to the rpm counter cutting out I first made sure that I have 2 good cdi s.
So then I have the same problem with the engine stopping but without the rpm counter and single cylinder issues. So I go to the fuel pump figuring this could be a combination of two problems at the same time.
I take out the fuel pump and connect it direct to the battery. No life so I buy a new HUCO pump and install it.
Everything works great except the rpm counter has cut out again but both cylinders are working fine!
Then the bike cuts out again. I check the Huco pump that I have installed by connecting it direct to the battery. It works with no problem so I check the power supply to the pump and find that there is no current going to the pump. So I have infact been running on gravity.

Can someone explain what controls the power to the fuel pump and how the fuel pump regulates itself. Does the power only come to the fuel pump if the reserve tank sensors work. My fuel level lights haven t worked for some years now. Are they connected to the fuel pump power supply. Is there a relay that cuts the electric supply to the fuel pump?

I m not too bother about my rpm counter not working so long as the two cylinders are running fine. This could just be an old counter with a dodgy connection that I m not going to try to find unless it is connected to the problem of my engine cutting out.

HELP, HELP !

[Xman]

Not sure why your rpm guage isn't working it may be just a coincidence but your fuel pump is fed 12v via a relay (under l/h side panel on an RD07) when your ignition is switched on. The fuel pressure is sensed by the pump, it sends fuel to the carbs when it senses low pressure and switches off when it is up to pressure.
The bike will run without a fuel pump or if you by pass it, until the fuel level is below the carbs and cannot feed by gravity.
It sounds like your problem is classic (erratic, running on one cylinder etc) pump failure, but as you say you have replaced the pump and it is serviceable...I would check the 12v feed from your fuel pump relay and also the fuses.
You can bypass the relay to diagnose the fault, but I wouldn't run it for long, there are fuel and sparks in awful close proximity within the pump, and the relay is there for safety.
Good luck

[ratty]

Thanks for your answer. Yes I m convinced it has to do with the power supply to the pump. To help me identify this relay is it a relay that is exclusive to the fuel pump and when you say under the left hand side panel do you mean where the air filter is, because I can t see any relay there.

[Xman]

Yes, I know it is under the L/H sidepanel on a RD07, but don't know where it is on yours. The relay just powers the pump. You could try a feed straight off a 12v battery to your pump and see if the motor will run, if it does. you know the relay is at fault...all you have to do is find it!!??
Someone here will Know.

Be careful though, if the pump is broken (like mine at the moment) sending an unfused 12volt supply to the pump could heat it up, and they get very hot!!!(I know I just did it!).

If you bypass the pump by fitting a connector to join the fuel lines together and fill the tank up with fuel, and it runs fine, you know that almost certainly you have a pump that is not running. So all you have to do is diagnose a faulty pump, relay, or open circuit somewhere (unlikely).

I am waiting for a Facet pump to arrive for mine, my pump is broken. It's not the contacts inside but the actual diaphragm inside not pumping. A Facet pump is only about 40 quid incl 10mm fittings and solid state, so much more reliable. Why Honda didn't fit one in the first place is beyond me!
Hope this helps.

[ratty]

Yep, it sounds like the relay as the pump does work when connected direct to the battery.
But I can t identify the relay without opening the whole cable package and following the wires which head off up to the "dash board" infront of the handlebars. My manuel makes no mention of the pump relay.
If anyone knows I would appreciate it.

[jonspan]

A thought, not sure about the 650 but believe on later bikes there is only a power supply to pump if engine is turning (i.e. on starter or running). So to check current to pump you need to turn engine on starter. Might answer question about failed or not relay but can't help with other issues.

[BobA]

Ratty


Welcome to the forum.

As you know, there are 2 CDI's on the XRV650 RD03, and one controls the front cylinder, the other controls the rear.

As well as this, one CDI sends a electronic pulse to the tacho/rev counter, and the other CDI sends a pulse to the contacts inside the fuel pump to make it work.

I would say start your testing again.

If one of the CDI units has developed a fault, it will affect the tacho in one of the wiring positions, and the fuel pump in the other.

If the fault stays with either the fuel pump or tacho when you swap them, chances are it is the wiring.

There is a guide for repairing the CDI, or some of the Transalp CDI's are compatible.

Let us know how you get on.




Bob

[Kjell Lindberg]

As usual BobA knows his way around the RD03

I would also at first suspect the CDI-box to be the problem, but by reading your description I'm not so sure.

I have a electric diagram or schematic for the RD03 that could be to some assistance.

I will post a part of a copy for you on this thread in a minute

//Kjell

Edit 1, after the minute:



Edit 2, after one more minute:

[BobA]

Some excellent diagrams Kjell has dug up there from his personal records


Looking at them, I'd say I might be a bit wrong, as the feed to the tacho and fuel pump seem to be from the same CDI and feed to one of the coils.

One of the black/yellow wires from one of the CDI's seems to feed the tacho and pulse circuit to the fuel pump.

I'm guessing that if you are getting intermittent problems with the tacho and fuel pump, not necessarily at the same time, it MAY be a wiring issue.

Check the connectors that plug into the CDI and make sure all the contacts and wires are clean and not damaged or loose.

I think you'll just have to work your way logically through everything, but with Kjell's info this will be a whole lot easier.

I'd be tempted to check or replace the coil that is fed on the same circuit as the tacho/fuel pump. If this is faulty, it COULD be shorting/breaking down (even momentarily) and this would affect everything else on that circuit.





Bob

[ratty]

Thank you for your very helpful replies. You have taken the mystery out of the problem/s. Now I just have to spend the time running through this. I m going to change the relay and swap some coils as I already have new cdi s and pump. Thanks.