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I had issues with rough idle and an engine that is reluctant to rev and trying to find out what is wrong.

I measured the lift on my cam while in engine and it is 0.25x", I also measured the cam by placing it in the lathe and using dial indicator and get the same value on all lobes. I expected the cam to be bad, I will upload a couple of photos later for you to judge but for me it seems fairly ok. The cam is marked Stanpart (in casting) and stamped VT102 at the end, is this a standard cam?


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0.25x?  What is the x?

I suspect it is a regrind of a standard cam.  Partly because I don't think the "VT102" is a Triumph marking (though I certainly could be wrong about that!) and partly because there doesn't seem to be much of the base circle left in the photo.  Getting the same lift reading on all lobes when measuring accurately does suggest that the cam is ok.  If you can also measure lift vs. angle for and inlet/exhaust pair it will reveal a bit more about it (sounds like you have the kit and expertise).  This might help once you have the numbers

If the bore of the rocker, where the shaft goes through, is reasonably good I'd probably just grind the pad until only a hint of the recess if left.

Bad idle might mean it is a rather aggressive profile and if the ignition and carburation is not altered to suit then it won't go well either.


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Thank you for your input, the x just indicates that the lift differed slightly between the lobes. I will put the cam back and measure lift vs angle, should have done so before I removed it....
If there is not much left on the base circle then the push rod must be longer or can this me adjusted by the ball pin?

Regarding the cam I think I will go for a new cam, haven't decided if will I go for a MKIII or TR5 profile, but still interesting to know what I have.

Kind regards

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