Bike lost power at speed

billo

billo

Joined
Nov 3, 2008
Messages
295
Location
san diego, ca
Bike
'07 ST1300
This is my first performance problem on this bike. A little background:
The past few times I've started the bike cold there has been a slight roughness in the high speed idle for about 30 seconds, then it smoothes out and runs completely normal for the rest of the day. Temps around her have been mid sixties to mid seventies. Bike warms up normally and shows three bars. The Iridium plugs have about 12k on them so I bought some new ones this week but haven't installed them yet. So Today I fill up with gas and jump on the freeway and get up to speed (80 degrees, 70mph) - bike was fully warmed up and ridden about 17 miles prior to gas station, no problem. It's downhill so I'm gradually letting up on the gas when near idle I feel the power drop. I looked down to see the FI light on. I give it a little gas and everything goes normal, bike runs fine the 7 miles home. No error codes. Ideas? Any help appreciated. Thanks!

Bill

P.S. Bike is an '07 with 37k on it.
 
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I doubt it is a vac leak (it would be persistent), but what you're doing can't hurt.

Sounds like an intermittent connector issue, perhaps. I think I'd reseat connections to the ECU just to be sure.
 
BakerBoy said:
I doubt it is a vac leak (it would be persistent), but what you're doing can't hurt.

Sounds like an intermittent connector issue, perhaps. I think I'd reseat connections to the ECU just to be sure.
Click to expand...

I'll do that. Thanks.
 
May be oversimplifying a bit here, but was the gas tank close to empty when you refilled? Did you get a top tier gas or a no name brand? If the latter fits, I think the first thing I would do is ride it as is if it runs reliably without stalling and still has enough performance to keep up with traffic, then refill with some name gas when it nears empty, after adding Seafoam to the tank. If you still have a problem, then it will be time to go to step B.
 
Of course, the first thing after a fill up, gas is always suspect. It was a name brand but you never know. Fuel pump? It will rear its' ugly head soon enough I suspect, if that's it.
I have tightened the manifold bands, replaced the plugs and reseated the computer connections. The bike runs great! We'll see...
 
Good to hear Bill.

FYI, When mine had fuel pump issues it didn't exhibit any sudden engine stalls or loss of power at speed--it always showed as bucking/surging when restarting the bike (when fuel & pump was heat soaked).

Another thought, probably worth ensuring the power connection to the fuel pump is seated well. You can find that connection under the seat, lower, forward, left. You may have to take off the left side panel (the panel that is below the seat) to access it.
 
Sounds like vacuum in the tank, have you had the tank up lately , maybe you kinked a vacuum hose at the back of the tank.

But what really stumps me is the fi light coming on. That points to some kind of connection problem. Not sure where to go on this one but back track anything you may have done lately.
 
I'll check the fuel pump connector too. I haven't done any work on the bike lately so this really did come out of the blue. Thanks again for your suggestions.

Bill
 
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