Morning Jim, Was it you, And if it was, Did you ever do anything with the single side, Honda ? rear swingarm, From the stevenage rally, Many years ago. Cheers Bill.
ET: Engine (Twin) Camshaft design
- Thread starter roger edwards
- Start date
Any photo's with the tank off ?
See what I can find, certainly do have several of the spare "bare" frame showing the rear suspension mount.
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This thread is "camshaft-design". I've moved a few posts to a new thread titled "Waiting for work to be completed". (Click the bold text to go to the thread.) Please try to start a new thread if you have strayed too far of topic. It makes things so much easier for people looking for information about a specific item if they don't have to wade through a load of posts that are off topic. Thank you in anticipation ....... 
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D
Deleted member 3831
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When discussing camshaft design, no one as yet has made comment on rocker flex, and how it will affect the valve lift curve. The Vincent rocker is extremely weak from the stiffness viewpoint, and the amount of flex that occurs in a running engine is considerable. If this is not allowed for in the static design, the end result will always be considerably reduced dynamic valve lift curve
Has anyone tested a rocker to see how much it flexes ? For those interested the attached illustration shows the method. If the X1 dimension is 300 mm, and the X2 dimension is 50 mm, an 8 to 10 Kg weight is sufficient, but the measured flex will be an alarming amount.
For a really stiff rocker, the flex should ideally be 0.002" but up to 0.007" is passable, and above 0.007" the valve lift loss will start to become excessive.
The flex is due to the lack of depth in the arms, and the inadequate material around the pivot.
This situation is impossible to realistically improve on while still retaining the stock installation arrangement, but the modified rocker mounting illustrated in an earlier post presented an ideal opportunity to improve the rocker stiffness dramatically. Unfortunately in the photo it seems not to have been done.
Has anyone tested a rocker to see how much it flexes ? For those interested the attached illustration shows the method. If the X1 dimension is 300 mm, and the X2 dimension is 50 mm, an 8 to 10 Kg weight is sufficient, but the measured flex will be an alarming amount.
For a really stiff rocker, the flex should ideally be 0.002" but up to 0.007" is passable, and above 0.007" the valve lift loss will start to become excessive.
The flex is due to the lack of depth in the arms, and the inadequate material around the pivot.
This situation is impossible to realistically improve on while still retaining the stock installation arrangement, but the modified rocker mounting illustrated in an earlier post presented an ideal opportunity to improve the rocker stiffness dramatically. Unfortunately in the photo it seems not to have been done.
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D
Deleted member 3831
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The rocker flex, although it may be considerable, is nothing compared to that occurring in a valve spring when it is is compressed.
If you consider that all metal components of an engine are made of some sort of rubber, you should get the idea - added to which they will all expand when subjected to heat.