The size of a new valve stem should be .3475" -.3485" and stem to guide clearance should be .003" -.005"....
If you take the major stem size and combine it with the recommended clearance that gives a valve guide bore dimension of .3515" -.3535"...
If the minor stem dimension is used and the clearance is then applied a valve guide bore dimension of .3505" - .3525" is the result...
9mm is .3543"....
So, in all instances, 9mm is larger than the bore of a correctly sized valve guide that has been sized off a valve stem that falls within the correct tolerances.
The finished bore of the guide would be within the range .3505" -.3535", the exact size within those dimensions being dependant on where the stem and clearance dimensions fall within the defined tolerance ranges...
If the guide being removed was worn then a 9mm punch may well fit but it would not fit into a new guide, which itself would not be finally sized until after it has been fitted and should therefore have a bore diameter smaller than .3505", or at least .004" smaller than 9mm...Ian
Thanks Ian,
Looks like I will have one drift for removal and another for insertion. Already ordered the 9mm.
I am taking in a WM20 to get running for a fellow Who got ripped-off by a motorcycle shop. Plus I am looking at another semi basket case with no history.
Trying to get parts and tools lined up.
Thanks Ian,
Looks like I will have one drift for removal and another for insertion. Already ordered the 9mm.
I am taking in a WM20 to get running for a fellow Who got ripped-off by a motorcycle shop. Plus I am looking at another semi basket case with no history.
Trying to get parts and tools lined up for the future.