Home Forums 250 Superkarts CR250 crankshaft options

This topic contains 8 replies, has 5 voices, and was last updated by  Ian Harrison 4 months, 4 weeks ago.

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  • #11341

    nigel cooper
    Participant

    The Honda CR250 replacement crankshaft is $400 (can)Thats alot of money for me(a cr125 crankshaft was only $260 can).

    Can I have the old crankshaft rebuilt? What about the aftermarket ones if I put it on the v blocks and ensure that it is within specs?

     

    #11343

    John Benson
    Participant

    Nigel try MrCycle . They have a 2005 crankshaft listed for $206.

    #11344

    Gerry MCN
    Participant

    what year ?

     

    USA OEM Honda parts can not be sold to a Canadian address, you’ll need a USA address or a friend in the states to buy it and reship to you

    #11347

    nigel cooper
    Participant

    its a 2001,even on ebay with shipping and customs it still would come out to over $400 (can)

     

     

     

    #11777

    Ian Harrison
    Participant

    Hi Nigel,

    The ’05 Honda crankshaft will fit in the Honda ’01 cases. It has a slightly larger O/D than the ’01 crank and sometimes (most times!) it is necessary to relieve the cases a little at around the 10 and 2 O’clock positions. The way to check this is to install the crank into each crankcase half in turn, fit the piston and cylinder and rotate the crank with the case laid horiziontally on the bench. You will see any positions where the big-end eye comes close or contacts the case and you can mark these areas for relief before final assembly.

    Generally the ’05 crank will be closer to the casings anyway, so if a big-end fails it is 99.5% going to damage/crack the casings.

    Another way to do this is to machine the flywheel circles and linish the big end eye O/D, but this really requires disassembly and reassembly, so would add to your cost.

    The reduction in crankcase volume will generally help low end power and into the midrange, but will restrict the over-rev. The advantages of the ’05 crankshaft are:

    1. You get rid of the tin shrouds

    2. A stronger big end (25mm pin)

    3. They are easier to rebuild/true/adjust the balance factor

    My experience with the Wiseco/Hot Rods Taiwanese manufactured replacement ’01 crankshaft, is that it can be supplied outside of tolerance and is harder to correct (due to the tin shrouds). Also that the tin shrouds can crack and peel off in less than a seasons use in a Superkart application.

    It is possible for the ’01 crankshaft to be rebuilt by a competent engineer with the correct equipment. When doing this I would recommend the Pro-X rod kits. But make sure the guy knows what he is doing and is used to working with the Honda tin-shrouded cranks. Get him to guarantee what tolerance he will work to and if possible check it before assembly. In Superkart use, our recommendation is, Season 1 new crank, season 2 rebuild, season 3 new crank, etc.

    $400 CDN isn’t so much for peace of mind.

    Best Regards

    Ian :-)

     

    #11825

    nigel cooper
    Participant

    Thanks Ian,

    amazing info again from the wizard of all thing Cr250. I`m leaning towards a rebuild of the existing crank by ken oconner racing.He has a youtube video explaining how he rebuilds them(special jig),uses the japanese pro-x parts (like you mentioned) and his website has an article explaining what you have said and the tolerances he has the crankshafts leave his shop.It really does look like he knows what he is doing.For $150 us dollars,plus shipping,I am ,at this point considering this option,if not-buy a new one.Either way  I will be checking it on my own vblocks before installing it.

    #11955

    Ian Harrison
    Participant

    Hi Nigel

    I’ve see the Ken O’Connor videos and he certainly knows what he’s at.

    The best way to measure a crank is between centres (make sure the centering cone on the ignition side is in good order), but V-blocks or knife edge rollers are OK

    Good luck

     

    Ian :-)

    #25101

    jeff
    Participant

    Ian, Who makes rod kits for the cr 250 2006 oem Honda crankshaft.

    #25112

    Ian Harrison
    Participant

    They are a Honda OEM part, so the vendor is not acknowledged/identified and I don’t recognise it as being from another established aftermarket supplier. What you can be sure of with Honda OEM parts is that they are of the best quality.

    However, we rebuild the Honda OEM crankshafts tinplate and 2005 on, using the Pro-X rod kits. We have found them every bit as good as the Honda OEM rod kits.

    Best Regards

    Ian :-)

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