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Cam timing made simple

Discussion in 'The Garage' started by jay760, Oct 28, 2019.

  1. grizld1

    grizld1 Grumpy old man Top Contributor

    Just to keep things on track, moving the cam against engine rotation means moving the sprocket into engine rotation (not being condescending here, I've seen a professional move the sprocket bassackward in a distracted moment).
    jay760 likes this.
  2. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

  3. Jack

    Jack XS650 Junkie Top Contributor

    Does smedspeed ship products to US?
  4. jay760

    jay760 XS650 Junkie

    Since the new owner took over who knows I contacted them for a price and availability on an adjustable can timing sprocket all I got as a reply was "yeah we've got one" I emailed again for a price and got no reply
    peanut likes this.
  5. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

    thats not good for business is it ! :(

    Pity Howard decided to quit ,he was a talented engine builder and extremely knowledgeable Engineer , His University Degree was based on the XS650 engine if I remember correctly
    Bewarethemoon likes this.
  6. Jack

    Jack XS650 Junkie Top Contributor

    They'll run that business into the ground eventually. What length manifolds are you using?
  7. jay760

    jay760 XS650 Junkie

    From memory 5 1/2 " may be a tiny bit longer, with clamp on dellorto clamped onto the length so center of carb isn't much farther out, they are also tapered on the last 2" 36mm to 34mm so they match the head ,
  8. jay760

    jay760 XS650 Junkie

    Just measured them they're 4 1/2" brings the dellorto to 6" center, tapered as I previously posted 2" from the end 36 to 34mm to match the ports, got another pair 2 1/2" got a feeling from memory these are the two measurements that miss the center post or at least make it so the chokes a possible to get to
  9. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey XS650.com Supporter Top Contributor

    That's very odd. I bought a modified sump and spin-on filter from the new guy - Rick Forte. He was very helpful and the service was prompt.

    Maybe I was lucky? There's a lot of technical stuff on their website but I guess that's Howard's legacy so I wonder if one can approach Smedspeed for engine work and so forth in the future?
    Bewarethemoon likes this.
  10. jay760

    jay760 XS650 Junkie

    Howard was always very helpful, always got back to you with a price and what he could do for you, in fact the 250-40 cam they have is a copy of mine, I was taken back a bit with the response I got from the new owner, perhaps I just got him on a bad day or he doesn't do emails
    Raymondo and Bewarethemoon like this.
  11. Jack

    Jack XS650 Junkie Top Contributor

    I plan on making some steel 3" manifolds. The steel would be easier in modifying at the end to a d shape. Longer manifolds should boost low to mid range performance,what's your thoughts.
    Also I found another resource for those virago valves,I'll let you know when they get here, real cheap and plan on snatching a few of them up if in deed they're 2mm oversize.
    Last edited: Nov 10, 2019
    gggGary and TwoManyXS1Bs like this.
  12. jay760

    jay760 XS650 Junkie

    If the valves are on eBay from Germany that's where mine came from

    I had my manifolds made in aluminium so the end could be tapered,, wouldn't like to say where the longer manifolds will help, it's just something I tried worked out it increased my terminal speed by around 5mph, stupidly I had some made for my competition so he uses them as well
    TwoManyXS1Bs and peanut like this.
  13. Jack

    Jack XS650 Junkie Top Contributor

    You'll never beat the opposing lane passing on your speed tips:D he good at least back off on the throttle every now and then:bike:
    Got two heads for 23.00 plus free shipping from another Yamaha CC motor,same valves:thumbsup:
    The part #s all checked out
    They're going to Germany on the D-Port
    Last edited: Nov 10, 2019
    TwoManyXS1Bs likes this.
  14. jay760

    jay760 XS650 Junkie

    EBay number 273974311889

    EBay number 273974311627
  15. Jack

    Jack XS650 Junkie Top Contributor

    I can't believe this, they're discontinued in US. Well at least these people ship to US and I know where to but new now,thanks;)
  16. Bewarethemoon

    Bewarethemoon XS650 Addict XS650.com Supporter

    I’ve known Rick for years, I grew up riding BMX with his sons. I’d say you’re probably much better off to phone him, I know he has a lot of other things on, so sometimes needs a little reminding.
    Last edited: Nov 11, 2019
    peanut and Raymondo like this.
  17. jay760

    jay760 XS650 Junkie

    They are not original yamaha each valve come in a bag with the number and marked racing valves,
    Bewarethemoon likes this.
  18. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Speaking of valves, here's some valve dimensions.

    For the XS650.
    Valve-XS650-Int.jpg Valve-XS650-Exh.jpg

    For the 750 Virago.
    Valve-XV750-Int.jpg Valve-XV750-Exh.jpg

    The Vesrah GG-2011 offering.

    If my fuzzy memory serves, I recall that Honda valves used standard diameter stems, we had to ream the guides to clearance.

    The Yamaha valves seem to be reverse of that, standard diameter guide bores, valve stem diameters ground down to fit...
    peanut and GLJ like this.
  19. jay760

    jay760 XS650 Junkie

    My other cam that I've just looked at which is unknown is

    Inlet 22 btdc 64 abdc 0.430 lift
    Exhaust 60 Bbdc 45 atdc 0.400 lift

    Any clues on this cam? I did have a thread on it but can't find it

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