give me the spacing between stanchion centers, and the offset from the stem centerline to the stanchion centerline,
The "Trees" of the title are unique - 6-3/4" between stanchion centres, upper "tree" doesn't have holes for Metalastik bushes for speedo./tacho. mounting, lower "tree" doesn't have the Zener heatsink mounting tab, steering stem is a nominal 3/4" o.d.; if you have a micrometer, the stanchion holes (in the lower "tree") are for 1.35" o.d. stanchions.
'69-on dry-frame trees will have one or more of those things, steering stem will be (1/4"?) longer, '69/'70 stanchion holes will be ~50 thou smaller.
Casting numbers are the same for twin and triple in both years, finished numbers for the lower tree are neither ("97-4038" is shown as the "finished" part number in the '71 T150 parts book). In addition to the aforementioned differences, there's also a difference to the rear edges of the casting. They were cast with a triangular block on each edge, that I believe were machined off for twins; on triples, these hit against the frame-mounted steering stops on full lock; oif have (a) different steering stop(s)?
Sorry for the faulty lower casting number. I took that from somebody's eBay auction. I have two sets - both bent in exactly the same spot - but the casting number is illegible on both.
Stuart, thank you for the info. Are the '71-'72 T150 "trees" the same, with the exception of the steering stem? These are for a "bitsa." I am set on running the conical front drum and forks, but if the T150 trees will work with the forks and drum, and have the dry frame 1.0625"(?) stem, that would be even better.
Are the '71-'72 T150 "trees" the same, with the exception of the steering stem?
Basically, yes - stanchions and 6-3/4" spacing between centres are the same on both twins and triples, conical front brake is the same too. As well as the cup-'n'-cone bearings stem on the T150 lower, it has a tab to mount the Zener (although many are broken off ) and, iirc, the triangular steering stop blocks on the rear edges. Btw, if your bitsa has a 'dry' frame, you know the steering stops unscrew and you can refit 'em with the smaller diameter below the steering head for more steering lock, as long as the forks then don't hit the tank?
Originally Posted by ogoki
I have two sets - both bent in exactly the same spot
I'm just realizing that the T150 stem might not fit through my neck cups. Could you confirm the stem diameter,
Originally Posted by BikeVice
I have an NOS 1971 T150 bottom yoke/stem and sleeve nut (1972 used a different stem thread pitch).
Oif and 'dry-frame' stem diameters are the same - I measured it as 3/4" with just a ruler but Dave Madigan posted on Triples On Line it's 0.748". The oif length is a little (1/4"?) shorter than the 'dry-frame' length.
Eric is correct about the threads: '71, the steering stem nut thread is 3/4"UNF - 16 tpi (threads per inch). '72-on, it's 3/4"UNS - 24 tpi.