Hi all,

Before the winter I put my bike away, stripped the bodywork off and have just finished having it resprayed. Because i'm an engineer (Forensic) and an idiot I removed the carbs, stripped them down, cleaned them and put them back on the bike. This is the first time I have ever done anything like this.

I tried to start the bike and she would turn over but not fire. To cut a long story short I identified that fuel was not being supplied to the carbs. Thanks to the help of Mr Haynes I bypassed the fuel cut off relay and the fuel pump worked so I ordered a new relay (£45 in total). I tried the new relay, flicked the ignition on and it still would not pump. I also checked all of the fuses I could find.

So after reading some posts, I bought a new battery because mine was quite old and there was a possibility that there was not enough current to close the contacts on the relay (£25). Alas that did not solve the problem.

This issue is seriously beginning to wind me up. Numerous times I have threatened the bike with chopping her in for a Street Triple but it doesn't seem to have any effect. Plus I just ordered the single seat cowl for her.

I am just about to take the electrical loom off and test every bloody sodding connection for the yellow and blue wire but I thought I should ask the community if there is something obvious that I am missing.

Any help would be greatly appreciated.

Regards,

Cuzy

Quick update: Got to spend half an hour with the bike. The earth wire on the fuel pump is in contact with the earth mounting point on the frame.

I have discovered that the yellow and blue wire from the relay has 'continuity' with the metal casing of the carbs. I am guessing this is bad?

 

Is it safe to assume the bike was running before you removed the carbs? In other words, fuel was being delivered to the carbs before they were removed? A relatively simple approach can be taken to see if the problem is carb related or electrical. If you have enough fuel in the tank gravity can replace the fuel pump. By-pass the fuel pump and try to start the bike. If no fuel is making it to the carbs still then you may have a kink in the fuel line, or a plugged inline filter, stuck float ,etc.
If the bike fires up then go hunting for the electrical issue.

 

The bike was definitely running before I removed the carbs.

Thanks I'll bypass the fuel pump through gravity.

I did bypass the relay so the pump was continuously working when the ignition was on but the engine flooded. But there was fuel in each of the float bowls.

I may have missed a major point in the first post. With the fuel pipe disconnected from the bottom of the carbs, when the ignition is switched to on, the fuel pump will not deliver fuel with the fuel cut off relay connected. I have to bypass the relay by placing a jumper wire on the black and black blue wires for the pump to work when the ignition is switched to on.

Thanks though, I'll check the hoses and the filter

 

Not necessarily as it goes to the spark unit and the tach. Could be finding a ground that way.
Does the bike run at all? The pump does not pump at all times while the bike is running. Usually at idle with the float bowls full, it will click very slowly. When gas runs out of the bowls , then the pump will speed up to fill them. I used to disconnect the pump to drain the bowls for winter.

 

My bike has similar symptoms. My fuel pump doesn't work unless the engine's running. I think of it as a post-crash safety device, but its probably just old age. So if I've worked on the carbs or the fuel's evaporated, the engine won't start due to lack of fuel in the carbs. So I prime the carbs by by-passing the relay, so the fuel pump chucks a load of gas into the carbs. Once the pump stops clicking, I reconnect the relay, and the old girl starts first bang of the starter button.

Not many other people seem to have this problem - dunno why my bike is different. For some reason the tacho doesn't work until 5- 20 seconds after the engine has started. May be related, because I think one of the fuel pump relay leads is connected to the tach.

Hope this helps.

 

Gearloose, you are a legend, it got working this evening!!!!

Not on the first attempt mind, but the engine did not die as normal and with continual persuasion she roared into life and sounds stronger than ever!!!

Thanks to everyone who offered assistance, it's good to know that there are people out there who are willing to help.


Regards,

Cuzy

 

Yeah Gearloose I have the same symptoms. If my bike is running it will restart no problem but if I wait overnight then try to start her she won't start unless I use starter fluid or jump her and pump the throttle a lot. For now on I will just bypass the relay much safer and good to know.

 

Thanks guys... could you each tell me... does your tacho start reading the revs immediately the engine fires up, or does the needle stay on zero for a while and then start reading the revs? There might be a clue there as to why the relay doesn't work and why other owners don't seem to have this problem. Thanks!

G

 

The needle stays on zero for a brief moment on my bike. I just never thought nothing of it.

 

That's good, thanks, a brief moment being... a second? Less or more? Thanks!

G