Hi all, I've not been on here for a good while as unfortunately I've had health issues. However, I fitted a new battery to my 92 first gen, carefully making sure that all was correctly reconnected. Went out for a test ride, around my usual test route (about 20 miles) and all seemed just fine. Then a week later with the (new) battery showing 12.69 volts at start up, I started the bike and ran it for a couple of minutes and then switched off and checked the tire pressures ( as i always do before riding). Then I set off slowly while the engine was warming up properly. After less than a mile down the road, I noticed that the engine didn't want to rev beyond about 3000rpm, then it got worse and quit completely. I had filled the gas tank with fresh 98 octane Euro gas ( about 95 US), so I'm sure that the fuel wasn't the problem. When I first started the bike before checking the tire pressures, all was normal (clicking etc while the carbs were filled up). After repeatedly trying to restart the bike, i gave up and had to push it home ( all uphill which nearly killed me!). I'm doing all of the test checks, but still no clicking on turning the ignition on. One other weird thing though was after the engine quit running I noticed the fuel light was on (very difficult to see in the bright sun here in spain), which was weird as I had just filled the gas tank. I tried it on reserve but still nothing. When I dismantled the bike I could see that the fuel lines were virtually empty. Also I noticed that the previous owner had fitted incorrect fuses in the fuse box, one of which was blown and of a too higher rating. I've changed all of the fuses for the correct ones now though. The mysterious low fuel light that happened previously does not come on anymore, which was a relief. At the moment I feel that I've narrowed the fault down to either the fuel pump or the fuel pump relay. I will be testing the fuel pump away from the bike later today. However I checked out the cost of a new fuel pump relay from Yamaha spain and was totally stunned to find that it was 315Euros, plus 21% sales tax!!!!! Staggeringly expensive for a small relay. I'm hoping if the fault is the fuel pump that i can get a pattern non yamaha one. So my question is how much is a fuel pump relay in the USA? I'm doing a voltage to the fuel pump test a bit later today. Which according to the tech service sheet should tesll me which of the components is shot (relay or pump) Has anyone got any ideas, as the price from yamaha spain is enough to provoke heart failure!!! Sorry about the long message but it seems to me important to give all of the syptoms of the fuel supply failure for anyone else to help out.
Fuel system electrical issues.
- Thread starter Tim spain
- Start date
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1992 fiche, look up the price here
1992 fiche, look up the price here
I checked out the power supply from the fuel pump relay to the fuel pump, with a fully charged battery, My test meter was showing 12.6 volts going into the fuel pump, for about 5 seconds then nothing. This seems to be correct, having tested with both the fuel switch on the main tank and also with the switch on reserve. The fuel pump itself looks like it might be the original one fitted, genuine yamaha. Putting power directly into the fuel pump from the battery (having disconnected the power lead to the pump) nothing at all, no noise from the pump at all and no signs of fuel movement in the lines either. So it looks like the fuel pump relay is OK and just the fuel pump itself is shot. But if the fuel pump is the original one, then it is at least 30years old. I can't complain as nothing lasts forever. I can get a new fuel pump here for a reasonable price (not genuine yamaha) so that is a great relief money wise. Finally when riding two up on the spanish autovia( US freeway equivalent) I had noticed before that at around 60mph (100KM) there would be a strange surging with a fixed throttle position, this was more noticeable when going up hill. At the time i felt that it was fuel starvation. So maybe the fuel pump was almost shot when i first got the bike. Anyway I'm getting a new fuel pump. I would like to thank everyone on the forum for being there, and hopefully my experience will be of help to others re the fuel system issues.
