Help Needed !!

[Team Toila]

Hi guys . just finished rebuilt on my sxv .550 .2007 and for about 500 m it works just brilliantly , after that all the power is gone and it doesnt rev and has no power .
Any ideas what could be the problem ? Ive heard that if the ECU recognizes any fault then it automatically turnes off one cilinder , don´t really know if that is correct or not . Any help is welcome ..

Martin

[swerver]

Do you have any way to connect to the ECU? Fuel line not kinked? Does the bike idle indefinitely or does it lose power even when idling?

[icho99]

do you check your spark plugs?, i had the same problem, 1 spark plug was bad, i changed the spark plugs and the problem finish

[Team Toila]

Fuel line seems to be OK . at that short time when it works properly it revs better while idling . after the anomaly starts then its feels like "hard working" sorry cant explain that one better as English is not my native language . I changed the spark plugs when reassembled the engine so there shouldnt be any problems . Now that i think about it , there was some issues with the first starts , my mates told that there was some sparks or smth that they saw on one side coming from one of the pipes and they saw them because one side was in the dark . Could that be the issue that the ECU recognizes some fault and turns one of the cilinders off ? The guy who told me that this model turns one cilinder off when it detects some faults works in the Aprilia Estonia .

[Targa Florio]

what were you valve measurements like ?

[Allen Noland]

Fuel line seems to be OK . at that short time when it works properly it revs better while idling . after the anomaly starts then its feels like "hard working" sorry cant explain that one better as English is not my native language . I changed the spark plugs when reassembled the engine so there shouldnt be any problems . Now that i think about it , there was some issues with the first starts , my mates told that there was some sparks or smth that they saw on one side coming from one of the pipes and they saw them because one side was in the dark . Could that be the issue that the ECU recognizes some fault and turns one of the cilinders off ? The guy who told me that this model turns one cilinder off when it detects some faults works in the Aprilia Estonia .

The ECU does not turn off one cylinder. It sounds like you have the cams out of time.

[Team Toila]

The ECU does not turn off one cylinder. It sounds like you have the cams out of time.

But then its weird that it works after starting it and then sort of loses power 2 minutes later , shouldnt it have no power all the time then ?

Martin

[Allen Noland]

Hi Martin,
These engines don't have a cam position sensor. When you start the engine, it runs in batch fire mode. The ECU "finds" the cam position by sensing an increase in crank speed and then switches to the normal firing/injection order. If one of the cams is 180 degrees out, it will start and run normally, but will feel like it has a "dead" cylinder after it switches modes. This process usually takes a few seconds, but I've seen cold engines start and idle perfectly for minutes, then loose power when you give them a little throttle.

[Team Toila]

Hi Martin,
These engines don't have a cam position sensor. When you start the engine, it runs in batch fire mode. The ECU "finds" the cam position by sensing an increase in crank speed and then switches to the normal firing/injection order. If one of the cams is 180 degrees out, it will start and run normally, but will feel like it has a "dead" cylinder after it switches modes. This process usually takes a few seconds, but I've seen cold engines start and idle perfectly for minutes, then loose power when you give them a little throttle.

Thanks for your reply . i got to ride with mine about 500-700 m . before it "died" . So basically you suggest that i turn one cam 180 degrees and then it should be ok ?

[Allen Noland]

I'm suggesting that you check the cam timing first.