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Help Spada Valve Timing

Discussion in 'Honda 250cc Twins' started by Ste, Jan 23, 2020.

  1. Ste

    Ste Active Member

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    An I missing something?
    I am attempting to set the valve timing using the manual found in Resources, but it's not working out right.
    Following the instructions for the rear cylinder and setting the crankshaft to T2 and fitting the camshafts I found that when I rotated 450deg clockwise the T1 mark was nowhere near the crankcase mark, that's when I realized that T2 is actually TDC for the front cylinder.
    So following the instructions for the rear cylinder I refitted the camshafts, but using T1. I then rotated 450deg and the T2 lined up and I fitted the front camshafts, everything seemed fine until I set the the valve clearance and found the engine would not turn over, the front exhaust valves were hitting the piston.
    I have double checked everything I can think of and can find nothing wrong, and have checked the actual valve timings, the rear cylinder is right and opens and closes when it should but the front cylinder seems to be about 50deg out.
    Its seems like the timing marks on the front camshafts are wrong, but they came out of this engine and it did just about run, the front cylinder seemed the stronger, when I stripped it I found that the rear cylinder was badly scored but everything else was ok.
    Anybody got any ideas before I attempt to re-time it ignoring the timing marks cos i`m baffled.
     
  2. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Is this the page you are referring to?
    Spada Cam Installation.jpeg
     
  3. Ste

    Ste Active Member

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  4. Ste

    Ste Active Member

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    Yes, and this page
     
  5. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    It is confusing as on Section 3 page 9 it shows adjusting the valves and it says T2 is front and T1 is rear.. maybe base your setup on that page. The only other thing you might want to check is that you didnt mix up the camshafts.. I know... it should be obvious but stranger things have happened.
    There is also the VT250F manual which should be pretty much the same for Cam installation (it is very much simplified in that manual) Section 10 pages 18, 19 and 20.
     
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  6. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    If in doubt, measure the lobes in the cams, higher lift should be the inlet cam but there are exceptions, check against the service data to make 100% sure.
     
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  7. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Its pretty simple on there... Front has Inlet on the right and rear has inlet on the Left
    Cam Position.jpeg
     
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  8. Ste

    Ste Active Member

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    If I am reading this right, in the VT250F manual it would appear that the camshafts for both cylinders are timed with the front cylinder at TDC, whereas the Spada instructions are for the timing to be done with each cylinder at it's own TDC. well that doesn't work, so timing the front cylinder with the rear cylinder at TDC might work. The next question is which TDC should I use, compression or exhaust?
     
  9. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Compression TDC is the only one to use.
     
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  10. Gizziracer

    Gizziracer Well-Known Member Contributing Member

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    Set timing with rear cylinder at top dead centre. The lines on both camshaft gears should be perfectly parallel with top of cylinder head in this position. Following the appalling instructions in the workshop manual will almost certainly end in tears .
     
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  11. Ste

    Ste Active Member

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    After browsing through the various manuals in resources I came to the conclusion that the method in the VTR250 manual looked right, I presume that is the vtr250 that was around at about the same time as the Spada, not the one sold in the UK in 2012, although they may be the same for all I know.
    Anyway the the engine turns over and the valves open and close in the sequence shown in the vtr manual, I couldn't make sense of the firing order shown in the Spada manual, maybe because it states that it's 52deg V twin. Of course i`m not going to know if it's right until I have the engine back in, and that may be awhile as I intend to restore the whole bike.


    Screenshot_2020-01-29 VT250 Spada WorkShop Manual(1) pdf.png
     

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