Engine test bed, good idea or should I put the idea straight to bed!
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  1. #1
    Member bikerdaily's Avatar
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    Question Engine test bed, good idea or should I put the idea straight to bed!

    Tell me if this is a daft idea!
    So I was thinking as I've got more engines than frames, that I could build a test bed to sit the engine I'm working on in! Cm250 engines. What would be the minimum I'd need to attach to the frame to get the engine to start. Has anybody done this? Fuel supply to carbs, plastic bottle and a tube? Throttle control? Sturdiness (concrete block) for kickstart, battery for electric start? Coils for spark plugs etc? What else? Would I need resistance to click through gearbox?
    Daft idea?

    Oculi plus vident quam oculus
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  2. #2
    Senior Member 76TWIN's Avatar
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    Lots of builders do this. You'll need an engine stand with a pole of sorts to attach the handle bar (need that for the throttle and clutch controls, etc...)
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  3. #3
    Senior Member 76TWIN's Avatar
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    Look at this video to see what I'm referring to

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    '73 CL450 (basket case for now)


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  5. #4
    Senior Member drydreamer's Avatar
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    Its a good idea, well worth the effort of making.

    You have engine bolt holes at front and rear, so an angle iron bracket made to fit the holes, with a wide "T" at the bottom, maybe screwed to some thick suitably wide wood beam/joist.

    A firm location or battery box, to bolt stuff like the reg/rec, cdi and coil to as well as the ign switch etc..

    Some sort of exhaust system, a quite one, and a dummy fuel tank with a tap. 1 litre would be sufficient.

    Study the wiring diagram and decide what's needed for that, an on off, an ign kill and the reg/rec black battery/load sense wire.

    Make provision for the dash, with lights ( oil and neutral ) as well as tacho.

    Have a fire extinguisher handy just in case.

    Computer fans for engine cooling.

    For low revs test runs, an airbox would not really be needed.

  6. #5
    Senior Member slofut's Avatar
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    Shop fan for cooling, I don't think computer fans would be up to the task. Also, be careful idling for long periods and top end oiling.

    Dang that 650 sounds good in the video!
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  7. #6
    Senior Member mike in idaho's Avatar
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    If you want new piston rings to seat correctly, you do NOT want a fresh engine to sit there and idle. It needs to be put under light to medium load very soon after it is started. Prolonged idling on a freshly honed bore will just burnish any microscopic high spots and hinder the ring seating process.
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  8. #7
    Supporting Member Yendor's Avatar
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    Nothing says it just has to idle.
    As long as you have throttle control you should be good.
    You could even get an old '60's era Generator and connect a Chain to apply some resistance.
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  9. #8
    Member bikerdaily's Avatar
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    Thanks for that. If and when I do it, I will post pics.

    Oculi plus vident quam oculus
    1981 Honda cm250tb rebuilding
    2013 BMW R1200R daily ride
    1980 Yam XT250
    www.hondacm250tb-biker.co.uk

  10. #9
    Senior Member Polish's Avatar
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    Quote Originally Posted by 76TWIN View Post
    Look at this video to see what I'm referring to

    WOW! Very neat, I like it.
    JL
    1979 CB 400 T (Cafe Racer)

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