Running Bad at Full Throttle
Posted: |May 5th, 2012|, 5:11 pm
This is an open and shut case, already solved it but thought it useful to post it here anyway.
The bike has been running great for a couple of weeks since getting it on the road, gave it a wash on Sunday ready for the week and took it to work on Monday, had to fill up with fuel on the way but it felt peculiar taking it to the petrol station.
I put this down to low fuel so filled up and set off down the dual carriageway to work, this is when the problems started.
The bike was fine at low and mid throttle position, would idle fine and ran best when cold.
I had set the fast idle cam on Sunday as well so did not know if that was the problem because when you opened the bike up, it died. it surged and slowly came to a halt. If you let go of the throttle it ran great, even after the surging at full throttle.
I had the same problem when the bike was new, the fuel cap had been changed under warranty so thought it was air not getting drawn in to the tank that was causing the fuel starvation.
Checked the cap and it was working fine, checked the vent (small hole inside fuel opening that exits near the side stand) and it was blocked. quick shot with the air compressor and it was cleared out. Thought I had fixed it.
Took it for another run and it did the same thing, stopped, opened the fuel cap and tried it again leaving it open, same problems so not the vent issue.
Wed night, drained all the fuel (full tank) and removed the tank off the bike, removed the fuel pump and filter as per the workshop manual and looked for the strainer, couldn't see it for a large, what looked like, ball of mud. The entire filter and gauze was caked in slimy brown crud. The metal casing of the fuel pump had started to rust and bad fuel dealt the death blow to the running.
Cleaned it up with fresh petrol and the compressor, replaced the fuel pump and filter, bought good quality petrol not from a supermarket and the bike is running better then ever.
I'm amazed it actually ran at all looking at the amount of debris in the tank.
Live and learn, only buying quality petrol and changing the filter regularly from now on.
When the bike was running bad, I tried holding it at about 9000 rpm in second (I think about 90ish mph) and it didn't hiccup, only at full throttle opening and in any gear.
The bike has been running great for a couple of weeks since getting it on the road, gave it a wash on Sunday ready for the week and took it to work on Monday, had to fill up with fuel on the way but it felt peculiar taking it to the petrol station.
I put this down to low fuel so filled up and set off down the dual carriageway to work, this is when the problems started.
The bike was fine at low and mid throttle position, would idle fine and ran best when cold.
I had set the fast idle cam on Sunday as well so did not know if that was the problem because when you opened the bike up, it died. it surged and slowly came to a halt. If you let go of the throttle it ran great, even after the surging at full throttle.
I had the same problem when the bike was new, the fuel cap had been changed under warranty so thought it was air not getting drawn in to the tank that was causing the fuel starvation.
Checked the cap and it was working fine, checked the vent (small hole inside fuel opening that exits near the side stand) and it was blocked. quick shot with the air compressor and it was cleared out. Thought I had fixed it.
Took it for another run and it did the same thing, stopped, opened the fuel cap and tried it again leaving it open, same problems so not the vent issue.
Wed night, drained all the fuel (full tank) and removed the tank off the bike, removed the fuel pump and filter as per the workshop manual and looked for the strainer, couldn't see it for a large, what looked like, ball of mud. The entire filter and gauze was caked in slimy brown crud. The metal casing of the fuel pump had started to rust and bad fuel dealt the death blow to the running.
Cleaned it up with fresh petrol and the compressor, replaced the fuel pump and filter, bought good quality petrol not from a supermarket and the bike is running better then ever.
I'm amazed it actually ran at all looking at the amount of debris in the tank.
Live and learn, only buying quality petrol and changing the filter regularly from now on.
When the bike was running bad, I tried holding it at about 9000 rpm in second (I think about 90ish mph) and it didn't hiccup, only at full throttle opening and in any gear.