Please help - high oil consumption

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by RedRupert, Feb 7, 2013.

  1. RedRupert

    RedRupert Brit in the Soviet Union

    Joined:
    Jun 12, 2006
    Oddometer:
    590
    Location:
    Riga, Latvia / Bergerac, France / Colchester, UK
    My bike had the crankcase breather valve installed as an official KTM modification back in 2005.

    I agree about the angle of the hone marks - my speed was low - should have been around 600 RPM (I used a battery drill) but I accept that I didn't plunge fast enough. However, I hope too shallow is better than too steep - logically it would seem so. Flex-Hone stated 'around 45 degrees' but I would not have known how to get to 45 without more practice, as you've pointed out.

    What oil did you use while running-in (break-in)?

    Thanks,

    Rupert
    #41
  2. Northyork

    Northyork Been here awhile

    Joined:
    Jun 25, 2009
    Oddometer:
    271
    Location:
    Canada
    Here is some info I have gathered from Amsoil's website http://www.amsoil.com/shop/by-product/motor-oil/gasoline/break-in-oil-(sae-30)/

    AMSOIL Break-In Oil is an SAE 30 viscosity grade oil formulated without friction modifiers to allow for quick and efficient piston ring seating in new and rebuilt high-performance and racing engines. It contains zinc and phosphorus anti-wear additives to protect cam lobes, lifters and rockers during the critical break-in period when wear rates are highest, while its increased film strength protects rod and main bearings from damage. AMSOIL Break-In Oil is designed to increase compression, horsepower and torque for maximum engine performance.
    Quickly Seats Rings
    The primary goal during engine break-in is to seat the rings against the cylinder wall. Properly seated rings increase compression, resulting in maximum horsepower; they reduce oil consumption and prevent hot combustion gases from entering the crankcase. To achieve this, however, the oil must allow the correct level of “controlled wear” to occur between the cylinder wall/ring interface while maintaining wear protection on other critical engine parts. Insufficient break-in leaves behind peaks on the cylinder wall that prevent the rings from seating. The deeper valleys, meanwhile, allow excess oil to collect and burn during combustion, increasing oil consumption. Too much wear results in cylinder glazing due to peaks “rolling over” into the valleys and preventing oil from collecting and adequately lubricating the cylinder wall.
    AMSOIL Break-In Oil’s friction-modifier-free formula allows the sharp peaks on newly honed cylinder walls (fig. 1) to partially flatten. The result produces more surface area for rings to seat against, allowing formation of a dynamic seal that increases compression, horsepower and torque (fig. 2).


    [​IMG]
    #42
  3. AdvRonski

    AdvRonski They call me......Ronski

    Joined:
    Feb 4, 2007
    Oddometer:
    728
    Location:
    Wishing I was back in Grand Junction, now in MN
    That's rather encouraging. Perhaps the Amsoil break-in oil will seat those rings.
    I just used a synth blend oil, and rode it like I normally do. Hard.
    #43
  4. Northyork

    Northyork Been here awhile

    Joined:
    Jun 25, 2009
    Oddometer:
    271
    Location:
    Canada
    Can it be used on a bike with wet clutch? Cannot find any info
    #44
  5. RedRupert

    RedRupert Brit in the Soviet Union

    Joined:
    Jun 12, 2006
    Oddometer:
    590
    Location:
    Riga, Latvia / Bergerac, France / Colchester, UK
    The info from AMSOIL is useful, but they are not well represented in the UK. However, a well respected British company, Millers Oils www.millersoils.co.uk have recommended two of their products. They have representatives in US and around the world.

    Classic Running In Oil

    http://www.millersoils.co.uk/scripts/tdsPrint.asp?prodsegmentID=240

    Liquid Glaze Bust

    http://www.millersoils.co.uk/scripts/tdsPrint.asp?prodsegmentID=165

    I'm going to try the Liquid Glaze Bust, as I've covered 12,000 km since the rebuild. The Classic Running In Oil sounds ideal for first fill after a rebuild.

    Millers have confirmed that both the above products are suitable for wet clutch engines.
    #45
  6. RedRupert

    RedRupert Brit in the Soviet Union

    Joined:
    Jun 12, 2006
    Oddometer:
    590
    Location:
    Riga, Latvia / Bergerac, France / Colchester, UK
    Update:

    I used the Millers oils as described in my last post, but oil consumption has not improved, just gradually worse. The bike has less power than a friend's 950 that I have recently ridden, so I'm pretty sure that I have lost power and well as a fair bit of oil!

    I'm a little surprised, as the Nikasil bores are very wear resistant and no step is evident; the piston ring end gaps were all OK and the pistons look pretty much like new - also with virtually no discolouration below the rings. Strange - oil was getting past the rings, but combustion gasses were not getting past in the opposite direction. Is that normal? KTM do say in the manual that pistons should be replaced if oil consumption is excessive.

    I never did check the cylinder for wear lower down - just at the top, as described in the manual - so it could be that the bores are worn lower down, or even a little oval. I have not access to the proper tools to measure accurately.

    Anyway, proper repair is uneconomical, and as the original 950 motor had covered about 60,000 miles, I decided to fit my nearly new 990 SD engine (with an ADV gearbox). The SD 990 motor produces a fair bit more power above 5k and about the same as a good 950 below. I'm very happy with the result. No changes to the carburation were necessary.

    I'm not sure what to do about the old 950 motor, as the 990 version is better in several ways, and worse in none. If I dismantle the top end to check it properly, I will no longer have a working spare motor. Neither will I ever get to know why the old motor burnt oil.

    Thanks to everyone who helped with advice and comments.

    Cheers

    Rupert
    #46