They have a ribbed rubber flange that measures about 1-5/8" across the opening

and bolt to the front crankcase bolt and then to your exhaust pipes that have tabs or threaded bungs for a nice sturdy pipe mounting

We carry manifolds for 1955-1965 Big Twins

there are 4 of these on each bike

so we went ahead and made one

Fork Tubes 1968 - 70 Triumph Motorcycles 500 / 650 c.c. #97-3904 Subcategory_Generators & Components They have a ribbed rubberStock length (22") pair of brand new fork tubes that fit 500 c. c. and 650 c. c. Triumph motorcycles from 1968 1970. Stock part # 97 3904. Don't forget to pick up a fork seal kit so you have everything you need to install your new fork tubes!