How to bleed coolant on 1190 RC8 engine

Discussion in 'Ridiculous streetbikes with 6 CPUs and too much HP' started by keener, May 13, 2014.

  1. keener

    keener Speed changes you.

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    We flushed the coolant on my friend's RC8 a week ago. It has the same engine as 1190 ADv of course. We followed the manual. Raised the front 50cm, opened bleeding screws and filled up the coolant then lower the front and fill up the expansion tank.

    The trouble is, bike keeps losing coolant when its hot through the expansion tank's drain hose. When it gets cold, coolant level goes bellow min. I repeated the bleeding process again yesterday, but nothing changed.

    Is this because there is still air in the system?

    I'm not sure what else we can do to remove the air. No bulbs coming out of the bleeding holes.

    On my 950, I don't even raise the front (even as it suggests on the manul). I just squeezes the 1" hoses several times and that does it. What's the trick with RC8?

    thx
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  2. Wissam

    Wissam Adventurer

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    I have the same problem. I could not bleed the system. Have you found a solution
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  3. keener

    keener Speed changes you.

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    kinda!

    I raised the front and removed the radiator cap. Then ran the engine and kept adding coolant as the level went down. Also I squeezed the hoses many times.

    Becarefull when you squeeze the hoses as it pushes the coolant into the rad so it may overflow if the level is high. Level can come up by itself too. You can hold something close the radiators mouth to capture most of it.

    Then I waited until fan kicked in around 94C and thermostat opened. Level when down,I pumped the hoses then added coolant.

    This got rid of most of the air. Now when bike cools down, coolant level goes back to almost where it was. It overflowed a bit during a ride afterwards but it was much less than before doing the no rad cap method.

    I think I should repeat this process one more time.

    good luck
    #3
  4. Alleycatdad

    Alleycatdad Unbunch yer panties!

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    Radiator cap?
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  5. fast4d

    fast4d Long timer

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    yeah, there is a radiator CAP on the RC8

    I'll change my coolant in the coming weeks as it is overdue.
    #5
  6. Alleycatdad

    Alleycatdad Unbunch yer panties!

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    No. Is your rad cap good? My 990 behaved exactly like you describe when the cap went bad.
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  7. keener

    keener Speed changes you.

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    may be. I replaced my 950 cap too. as preventative maintenance because I knew it will fail.
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  8. keener

    keener Speed changes you.

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    I though I make an update, because I finally managed to bleed the RC8 cooling system.

    There was nothing wrong with the cap.

    I raised the front 50cm then ran the engine and took the radiator cap of every now and then to check if coolant level had gone down. Topped it of as needed.

    I waited until fan came on so I am sure thermostat is open. I shut the engine and opened the bleeding screws on the engine. Lots of air came out. More from the front cylinder.

    I ran the engine again until fan came on and repeated this process about 4 or 5 times.

    Every time I bled the system I topped of the radiator. Note make sure bike is on level ground from side to side so u don't have to open the bleeder screw on the top of the rad.

    When the fan comes on wait a few seconds before killing the engine so coolant gets a chance to circulate .

    I lowered the bike and added coolant to expansion tank as needed.

    On my LC8 950 to know if system is air free, I mark the coolant level on the expansion tank when COLD, then I go for a ride to warm up the engine very well. Then I let it cool down for couple hours and check the coolant level on the tank. If it is not significantly higher or lower I know there is no air in there. I did the same for the RC8.
    #8
  9. mcguyver

    mcguyver Long timer

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    Keener
    Could you please tell me which are the bleeder screws on he head.
    #9
  10. Katoom72

    Katoom72 Been here awhile

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    Page 196, 5th picture
    #10