premix
  • Colorado Rider
    Posts: 22
    Joined: Fri Feb 24, 2006 12:46 pm

    premix

    by Colorado Rider » Sun Apr 01, 2007 6:29 pm

    I have been riding four strokes for the last 4 years and I just got my old (82') CR-250r back from a friend. He left it sitting for the last couple years. Trouble is I don't remember the pre-mix ratio. Anyone help me out , thanks.
  • Asmith
    Posts: 14381
    Joined: Mon Apr 10, 2006 7:52 am

    by Asmith » Sun Apr 01, 2007 7:40 pm

    40:1 is a safe ratio. If that's too rich drop to 32:1.
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    JAWS
    Posts: 4449
    Joined: Fri Jun 16, 2006 6:59 am

    by JAWS » Sun Apr 01, 2007 7:45 pm

    It depends on the oil you are using. There are some oils that are formulated to run at 100:1. Which oil are you using?
    Joe
    Image
    '05 CRF450X,McClain suspension, Cycra Probends, Pastrana FMX Pro Tapers,BRP Sub mount & Scotts stabilizer.See carb sticky for more
  • Aussiecrf230
    Posts: 1962
    Joined: Fri Jan 06, 2006 11:11 pm

    by Aussiecrf230 » Mon Apr 02, 2007 4:15 am

    I think bikes of that vintage ran anything from 20:1 to 32:1.

    A 2001 CR80 runs 20:1 standard. The bike shop keeps telling me it will foul plugs etc.
    Plug is clean as a whistle, as is the piston, and piston and rings last.

    Don't believe oil makers claims they don't pay for piston seizures and crank replacements.

    PM Oldtimer he runs a CR250 not sure what year though, but I would bet he knows.

    If you do run different mixture rates remember you will have to adjust fuel amount.

    More oil bigger jets, Less oil smaller jets.
    You would be surprised.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • Colorado Rider
    Posts: 22
    Joined: Fri Feb 24, 2006 12:46 pm

    by Colorado Rider » Tue Apr 03, 2007 10:05 pm

    I am using pro honda GN2 pre mix oil. Anyone have any sources for vintage plastic and seat covers? Thanks.
  • User avatar
    124
    Posts: 3704
    Joined: Wed Feb 16, 2005 1:37 pm

    by 124 » Wed Apr 04, 2007 5:29 am

    ~ wrote:40:1 is a safe ratio. If that's too LEAN drop to 32:1.



    Fixed ;)
    70' Honda CT70 (Trail 70; Gold)
    16' KX450
    16' KX85
    12' YZ125
  • Asmith
    Posts: 14381
    Joined: Mon Apr 10, 2006 7:52 am

    by Asmith » Wed Apr 04, 2007 5:35 am

    124 wrote:
    ~ wrote:40:1 is a safe ratio. If that's too LEAN drop to 32:1.



    Fixed ;)


    I thought increasing the amount of oil to gas will lean the mixture. You are saying that will richen it???
  • Praetorian
    Posts: 5
    Joined: Fri Jul 11, 2008 9:10 am

    by Praetorian » Mon Jul 21, 2008 11:37 am

    I would run 32:1 in a 250 as previously suggested. I run 44:1 in my CR500. If I may recommend Maxima 927. Its a great premix!!!! Smells purdy good and is castor based. You cannot beat the protective properties of castor. It has an affinity for hot metal surfaces. Most synthtics burn off well before castor does. When it does burn it leaves a lubricating film.
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    krisrtch
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    by krisrtch » Mon Jul 21, 2008 11:43 am

    I run 50:1 full synth either Panolin or Golden Spectra oil in my 06 CR250R Still runs as strong as the day I brought it home new still has orginal piston in it.
    There is plenty of time to sleep when your dead....... Ride Hard!!!
    2012 CRF450R
    2010 CRF250R
    2006 CR85R
    2012 CRF50F
  • User avatar
    124
    Posts: 3704
    Joined: Wed Feb 16, 2005 1:37 pm

    by 124 » Mon Jul 21, 2008 12:09 pm

    ~ wrote:
    124 wrote:
    ~ wrote:40:1 is a safe ratio. If that's too LEAN drop to 32:1.



    Fixed ;)


    I thought increasing the amount of oil to gas will lean the mixture. You are saying that will richen it???


    I just realized that I had left an open question AS...and ofcourse you already know the answer. :roll: I think I was responding oil/gas ratio vs air/fuel ratio. There was discussion of both in this thread. Who knows what I was thinking...I don't half the time. :oops:

    Anyways, 32:1 or 40:1 is close to stock jetting for premix ratios. If it matters anymore...I'm diggin the NO PREMIX! Haha...
    70' Honda CT70 (Trail 70; Gold)
    16' KX450
    16' KX85
    12' YZ125
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    ship_killer6666
    Posts: 284
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    by ship_killer6666 » Sat Aug 23, 2008 5:54 pm

    40:1 is too lean

    I range from 30:1 to 35:1, depend on the oil
    also try having your jetting a bit too rich on gaz/air. remember it is a two stroke and your crankshaft life depend on the small amount of oil in the gaz

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