suddenly revving high

[bizza]

Hey, any help with this would be appreciated, I'd normally get a mechanic to take a look, but I'm kinda broke atm...

Bike is a '94 M600

Here's what happened:

I was on my way home from work in the rain last night, I got to my street and the bike just suddenly started revving really high, like the throttle was 3/4 open. Switched it off, started it again, still revving high. Waited til morning, went down, checked the accelerator cable, it isn't getting stuck anywhere and the throttle closes all the way, it's just revving high for some reason.



Other things that may help with the diagnosis:

A couple of weeks ago, on my way home from work (at night - during the day I never experienced this problem) it was losing power as I applied throttle and the only way for it not to slow down to a stop was to apply 1/3 throttle or less. I attributed it to dirty fuel (it started doing it not long after filling it up) and just to be sure, because I heard high octane can be a problem with some ducatis, I switched from vortex to regular unleaded, filled it up and it seemed to be ok...

The other day, again after work, when I first started it up it was acting like it was gonna stall so I gave it a bit of choke. The choke seemed to be ineffective though, so I pushed it back in and just gave it a few revvs.

Last night, it was doing the losing power thing again on the way home. It was low on fuel and it's been raining a lot, so I figured some water may have gotten into the tank and was making it's way to the carb with the fuel being low, so I pulled into a servo and filled it up. Leaving the servo, I gave it to her a bit more than normal to clear whatever crap out of it's system. It seemed to be ok by the time I got home until the revving thing.




Any help/suggestions would be greatly appreciated. I really don't wanna have to catch the bus to work until I can afford to get this fixed...

[Mr.S2R]

check that the carbs arent loose.  if air is getting in betting the seal between the carb and manifold that can attribute to the symptons you are describing.  otherwise you may have crap (technical term  ) in the bowls affecting the float, need and jets.  taking the carbs of and cleaning them is an easy job.

I am sure someone else will post some more and quite probably technically correct advice!  But here is a start!

[bizza]

check that the carbs arent loose.  if air is getting in betting the seal between the carb and manifold that can attribute to the symptons you are describing.  otherwise you may have crap (technical term  ) in the bowls affecting the float, need and jets.  taking the carbs of and cleaning them is an easy job.

I am sure someone else will post some more and quite probably technically correct advice!  But here is a start!

thanks for that, I'll take a look over the weekend. Are there any guides around? I've only ever in the past attempted the most basic of maintenance.

edit: preferably a guide with pics

[loony888]

MR.S2R has made a good point, i'd definitely be checking for cracked and perished manifold rubbers, as well as that i would (if it has one) change the fuel filter and drain the float bowls and the petrol tank. once the tank is empty, there is a bung on the lhs rear iirc flush it with metho to see what crap has stuck to the sides etc. give the hoses a good going over and make sure they're not cracked and perished also. if you need to replace the rubber hoses inside the tank make sure you use IMMERSIBLE fuel hose, normal stuff will deteriorate very quickly, and efi hose will NOT do inside the tank.

paul.