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Discussion Starter #1
Just picked this bike up and noticed its got a pretty good oil leak on the left side. Does anyone recognize this mess and where it could be coming from. Many thanks

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Possibly just chain lube....but also could be the sump gasket. The side stand bolts into it. Known source of leaks. Check the sump pan bolt tightness.
 

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The first two photos show source of oil coming from above the messy area, so +1 for me on chain lube, or perhaps countershaft seal (but this is a pure guess as I don't know if this is common on MVs).
 

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My 750 F4 did the same (same engine) , it was the sump gasket and needed a new one. It was the MOT station that caused it as they tilted the bike on the side stand to raise the rear wheel to check for play. Was not happy and never went to the MOT station again.
 

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leaky bitch?

my vote.....countershaft nut isn't torqued correctly

oil is too high up for it to be the pan gasket

:wink2:
 

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I had that mess, for me it was the water-pump O-ring, I got the proper size from a hardware supplier, stopped the leak. You can remove the water pump without having to disconnect/drain the coolant. To check, take off the bolts holding the pump in place, pull the thing out to see if that's the source of your leaks.
 

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Agree with Donsy, give everything a good clean first. I had a similar problem on my 910S and initially thought it was too much chain lube but turned out that was just the clean engine oil mixing with dirty chain lube, becoming black in the process and getting flung everywhere.

I also pulled my countershaft/front sprocket cover and degreased behind there.

Turned out I had two problems, the first slightly unusual and almost certainly originated at build. The slots on the front sprocket nut lock washer were slightly misaligned with the countershaft splines during assembly and partly folded over as the nut was tightened. The effect of mangling the lock washer prevented the full torque being applied to the nut, only the lock washer tab prevented the nut from coming undone. When I knocked back the tab the nut was just finger tight. Having gone that far I changed the countershaft seal and reassembled everything to find the leak returned, albeit reduced.

I also had a leaking sump gasket, split right next to where the side stand mounts. I pulled the sump, cleaned everything up and used Toyota liquid gasket on reassembly. No more leaks. Hope this helps.
 

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?

Sundodger;
At a correctly applied 140 Nm, a slight misalignment of the lockwasher won't matter....... it'll seal

:wink2:
 

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Sundodger;
At a correctly applied 140 Nm, a slight misalignment of the lockwasher won't matter....... it'll seal

:wink2:
Noel, Maybe I didn't explain myself too well and with hindsight a picture of what I found when I stripped my bike would have probably explained it better but to be honest, all I wanted to do at the time was get the bike back on the road.

The lock washer was more that slightly misaligned,, it was more like half a flat out if you see where I'm coming from and if you stop and think about it, most of the effort (torque) being applied to the nut with the washer misaligned that much is being used to crush the washer down against the sprocket instead of pulling the nut down hard. About half of the castellation on the washer that is meant to reside within the spline on the countershaft was bent back through 90 degrees which also made the contact surface far from flat. Think about torquing up badly corroded or poorly threaded fasteners if you like, you'll never get a true torque value as much of the effort is expended overcoming the poor threads, not in applying the required degree of stretch to the bolt. In the case of my bike, much of the effort would have been expended crushing the washer into place.
 
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