Hi guys, Hoping for a little help! Had my 748 for around 6 months...first 6 months have been perfect...no better than perfect. The bike is everything I wanted it to be...however. It has recently developed a fault. Due to her being a second bike I tend to only ride her in the dry and one evening returning from a ride I got caught in a shower. Since then the bike has been dropping on to one cylinder...sometimes it won't rev over 5k...splutters and stutters accelerating....it will sometimes idle lower then norm then shut off. At first this was intermittent...as turning her off made the issue go away. Now it is constant. Sometimes she looses all electrical power for a few moments. The problem seems to occur when the bike gets up to running temperature. Any ideas what this could be? It may have nothing to do with the rain and that was just a coincidence....help greatly appreciated!
You need to determine which cylinder and then try swapping plugs etc to see if the fault follows what you swapped or stays with the same cylinder.
The up-side of it getting worse is that it should become easier to diagnose. Intermittent faults are a nightmare.
Has it only lost all electrics ONCE, if not sounding like a wiring loom problem. As the one time you lost power they ignition key might have moved??
Loom would be my guess but no idea if front mid or back section but i suspect water ingress somewhere or a broken/split section perhaps
Missed the bit about losing all power. If switching off and back on cures it, it could be a broken/pinched wire or a corroded connector or fuse holder.
Weird that you should lose all power sometimes and just one cylinder at others. Could it be the ecu earth not making proper contact perhaps? That is supposed to produce weird symptoms.
No several times. Could it be coil related? The water ingress sounds like a possibility. As does a lose or damaged connection somewhere.
Sounds like you may have two faults, one affecting one cylinder and one affecting the whole system. If switching off and back on brought the electrics back, it could well be a loose or corroded connection. First thing I'd check is battery terminals, then fuses, then relays, then other connectors. I had trouble with the highest rated fuse in the fuse box on my SS. It's essential that the fuses are completely flat with no twisting. If the fuse is twisted the contact area becomes tiny.
My bet would be corrosion on some of the socket poles in the electrical system... My 998 sis some of the same things but only when it was over 80-90 degrees celcius..
Had similar on my 748 when the rubber boot on the pressure sensor had perished/split and let water into the sensor plug contacts (this is the sensor on the water header tank under the RHS of the steering damper). One of the three pins was white with oxide when the plug was pulled and you could see where the water had been sitting leaving a tide mark . It would loose power then run on one cylinder then cut out completely, would restart, but that was dependant on running temp and it was most prevalent on hot days when it was over 70F outside. The fault was confirmed with diagnostic check but I had already cleaned up the contacts in the connection plug socket and got the bike working. It is worth pulling apart just about every connector to check for cleanliness and if you get some contact cleaner/preserver spray give them a good spray to include the ignition barrel and handle bar switches - do not use wd40 to do this. Also check the yellow relay and big fuse contacts down by the battery and the two relays/and fuses under the seat.
Thank very much for the advice. I will have a good look this weekend. In checking the fuses...a small fuse in right next to the battery (right hand side) had blown. What fuse is this? Could this be causing the problems? Thanks Ric
Ricardo, the main 40A fuse is located just to the right and below the battery near the starter solenoid, it is a big fuse. Is the small fuse on a flying lead from the battery positive post or in the fuse box with a few others but located above the battery? Perhaps a photo??
I have a 996 still and during the beginning of the year had to do a major engine repair. I was quick shocked how much corrosion was evident on some of the connectors. I invested in a small fibre pen like this- http://www.halfords.com/motoring/paints-body-repair/fillers-preparation/abrasive-pencil-4mm and took 30 mins cleaning off the surface of connectors, many were green.... not the best colour for a connector surface ( only beaten by Black/ on fire) also check the battery connectors and earths, and the regulator cable. but the first step I would take before anything is to replace the pugs and see what happens as they are low cost items.
happened twice 900 super light and F1, trigger coil? change the ignition coils over if problem shifts cylinder buy 2 new coils if not try the trigger coils hope you get it sorted mine would start on one cylinder and the second would fire up after a while?
Dicky connection somewhere.As mentioned above,connectors corrode anyway.It wouldnt be a bad idea to pull them apart,one at a time, give em a clean and bung em back together.
Had a good look at the weekend. Exactly as you said...one of the sensor plugs was white with oxide so I have cleaned it all up. Also changed the small fuse on the flying lead. What is this for? I will take her for a ride tonight....fingers crossed!
Yep, they dont't like water... I clean EVERY switch/plug every winter. That makes a huge difference in timesaving wen it comes to searching for weard faults
