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How to check if M8 bikes are 'transferring' and pumping the gearbox dry.

  • Nutty
    Nutty
    5 years ago
    Set gearbox oil level to centre of 'X' on dipstick with bike on lifter.

    Set primary oil height at 12mm BELOW the square notch at the bottom of the clutch cover. 

    Every 4000km and before each dealer service check primary height is still spot-on 12mm.

    * helps to use 20W50 full syn oil in primary and 75/140 or similar in the gearbox. Oils of differing colours also make the issue easier to spot.

    The MoCo have made four! (4) different slave cylinder seals and three (3) different oil slinger set-ups trying to fix the issue.  We've cured the problem and info for fix is free if your bike is a transferer. 

    Note : Dealers use Formula+ in both holes and cannot spot transfer. There's NO HD service method for detecting transfer. 
  • Grease Monkey
    Grease Monkey
    5 years ago
    Hey Nutty, good on you for trying to get the info out to the masses, don't worry if not many seem to take it on board, lot of people just don't want to know.
    So what are you saying is the definitive fix?
    I been following the threads on HTT so aware of Maddo's considerable input into solving the debacle, there was a lot of brainstorming going on.
    Seems there are a few things you can do that can stop it but not many on here would be aware of them all.
    I'm near convinced just slotting the cover out so the oil can't stay around the pushrod would do it, venting the primary can't hurt either and can help as well, the AIM slave cylinder is just a better mousetrap in my view, I'd have one anyway just for the improvement in friction zone.
    The Fat Rod has stopped some transfering but it's a band-aid solution in my view as it doesn't address the cause.
    I just check my gearbox dipstick regularly to make sure it hasn't changed, mine is a twin cam but it's the same HYD set up as the M8 so prone to it as well.
    I have a few pics saved of the various mods if anyone is interested, Nutty you probably have better ones?

  • Nutty
    Nutty
    5 years ago
    Quoting Grease Monkey on 11 Apr 2019 10:08 PM

    Hey Nutty, good on you for trying to get the info out to the masses, don't worry if not many seem to take it on board, lot of people just don't want to know.

    So what are you saying is the definitive fix?
    I been following the threads on HTT so aware of Maddo's considerable input into solving the debacle, there was a lot of brainstorming going on.
    Seems there are a few things you can do that can stop it but not many on here would be aware of them all.
    I'm near convinced just slotting the cover out so the oil can't stay around the pushrod would do it, venting the primary can't hurt either and can help as well, the AIM slave cylinder is just a better mousetrap in my view, I'd have one anyway just for the improvement in friction zone.
    The Fat Rod has stopped some transfering but it's a band-aid solution in my view as it doesn't address the cause.
    I just check my gearbox dipstick regularly to make sure it hasn't changed, mine is a twin cam but it's the same HYD set up as the M8 so prone to it as well.
    I have a few pics saved of the various mods if anyone is interested, Nutty you probably have better ones?

    You're 100% correct GM. Simply milling the cover fixes the issue. The S/C diaphragm design is a shocker and the MoCo is on its 4th version. The part is made by Brembo so it's not a quality thing, it's a design issue.  

    The Aim-Tamachi S/C is far more than just a 'better mousetrap', because it has no edge-seal it breaks and bleeds off the oil passage responsible for transferring.  It helps in its own right.

    The combo of milling, the Aim-Tamachi slave and a vent just bulletproof the job. They also shift smoother with the mods done. 

    I recently installed a RSD prototype  milled cover and it works perfectly as well. 
  • Grease Monkey
    Grease Monkey
    5 years ago
    Seems the moco have decided the breather in the primary will be their get of jail free card, seen this on HTT...

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  • Nutty
    Nutty
    5 years ago
    Ha! Mine is made from OEM Yamaha and KTM parts and I reckon it'll work better than that. That's mounted too low in the assembly and has no one-way valve. I can see that pushing a fair load of oil around...
  • Grease Monkey
    Grease Monkey
    5 years ago
    Quoting Nutty on 14 Apr 2019 02:19 AM

    Ha! Mine is made from OEM Yamaha and KTM parts and I reckon it'll work better than that. That's mounted too low in the assembly and has no one-way valve. I can see that pushing a fair load of oil around...

    I'd be doing it as you blokes did it for sure, as usual their cure is half arsed and minimum cost.
    They know Nutty, they must do aye 
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