Cam timing made simple

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).
 
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
 
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

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

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?
 
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?

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
 
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
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.
 
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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
 
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
 
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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;)
 
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

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.
 
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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.
Vesrah-GG-2011.jpg


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...
 
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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