1 Fuel Issue (I think). FPR or Air Meter? Wed Sep 22, 2010 9:45 am
The Chad
active member
Hi all,
I've been lurking the forums for a while trying to figure things out. Just want an opinion of what you think my issue may be. Picked up an 86 k100rs with 27,000 miles on it. It had been sitting for a long time and he no longer could get it started. I got the bike home, and she fired up with a little hesitation, backfired and smoked for a minute, then smoothed out. I rode the bike for about 5 miles with no apparent issues before she suddenly died. Wasn't able to get it started again and had her towed back to the house.
First thing was first, I couldn't hear the pump. I was surprised it actually worked for 5 miles after I pulled it out (it was rusted bad). Also, the previous owner had coated the inside of the tank with a sealant a long time ago, and that sealant paint was peeling inside the tank. So I spent a few days and removed all of the sealant from the tank, I replaced the fuel pump, I replaced the fuel filter. Again she wouldn't start. Pump was not working. I eventually poked and prodded with a multimeter and found that the fuel level sender unit and power leads had a short in them right at the junction of the wires into the tank. Since the fuel level sender unit was rusted, I simply removed it and re-soldered the power lead (ground was still good) to one of the sender unit leads.
The bike came back to life, somewhat. Got a block down the road and it started sputtering again and stopped.
Here are the symptoms:
Starts fine
Idles fine
bogs down when given a touch of the throttle but can get it to rev to about 3k rpm before it bogs down again and dies.
smells flooded
I've changed the spark plugs, old ones were wet and semi fouled.
I've checked the spray pattern of the injectors and they seem to be misting just fine.
Now I have the air box out and the FPR out. When I removed the FPR, there was positive pressure on the rail side of the FPR (it sprayed pretty good). I'm going to try the best I can to test the Air Meter according to the trouble shooting guide, but will need to go get an temp gauge first.
Any ideas as to the symptoms described?
I've been lurking the forums for a while trying to figure things out. Just want an opinion of what you think my issue may be. Picked up an 86 k100rs with 27,000 miles on it. It had been sitting for a long time and he no longer could get it started. I got the bike home, and she fired up with a little hesitation, backfired and smoked for a minute, then smoothed out. I rode the bike for about 5 miles with no apparent issues before she suddenly died. Wasn't able to get it started again and had her towed back to the house.
First thing was first, I couldn't hear the pump. I was surprised it actually worked for 5 miles after I pulled it out (it was rusted bad). Also, the previous owner had coated the inside of the tank with a sealant a long time ago, and that sealant paint was peeling inside the tank. So I spent a few days and removed all of the sealant from the tank, I replaced the fuel pump, I replaced the fuel filter. Again she wouldn't start. Pump was not working. I eventually poked and prodded with a multimeter and found that the fuel level sender unit and power leads had a short in them right at the junction of the wires into the tank. Since the fuel level sender unit was rusted, I simply removed it and re-soldered the power lead (ground was still good) to one of the sender unit leads.
The bike came back to life, somewhat. Got a block down the road and it started sputtering again and stopped.
Here are the symptoms:
Starts fine
Idles fine
bogs down when given a touch of the throttle but can get it to rev to about 3k rpm before it bogs down again and dies.
smells flooded
I've changed the spark plugs, old ones were wet and semi fouled.
I've checked the spray pattern of the injectors and they seem to be misting just fine.
Now I have the air box out and the FPR out. When I removed the FPR, there was positive pressure on the rail side of the FPR (it sprayed pretty good). I'm going to try the best I can to test the Air Meter according to the trouble shooting guide, but will need to go get an temp gauge first.
Any ideas as to the symptoms described?