The exhaust was changed at engine T500-11521 from 14301-15002/14302-15002 for the right and left mufflers to 14301-15003/14302-15003 to include a longer baffle. The baffle was lengthend from 435 mm to 475 mm
The horn was mounted on a stud fitted into a rubber bush on the left side of the frame under the tank, and was specific to the MK I
The early MK I swing arm didn't have a grease fitting.
The early MK I and at least some MK II air-box were part number 13700-15070 which changed to 13700-15071 through to the end of the 'J' production. Externally they all looked much the same (the holes drilled through the sides were an optional extra courtesy of the PO which I filled in). The third shot in the stack shows the inside of the box, without the filter assembly.
Internally, the early MK I air-box had just a simple air filter mount as seen in the photos on the left side of the image. The MK II introduced the twin cylinders, likely to try and reduce the induction noise. The MK III (and presumably later through to the 'J') had both the twin tubes, as well as a foam liner.
There are three different battery boxes. The earliest one (41540-15000) has a rear double wall and a riveted copper/brass wire clip. This changed to 41540-15001 which still has the double wall, but a spot welded steel wire clip. The GT series had 41540-15002 which had a single rear wall.
The forward tank mounting lugs are mounted low and forward on the head stock gusset.
The MK I rear shocks can be easily disassembled for painting, as the top eye just unscrews from the shock rod freeing the top shroud.
The MK I, II and III handle bars all ran the wiring inside the bars, and had a reinforcing collar indicated by the arrow in the photo to the right. The MK I bars (56110-15000 in the earliest parts manual I have) did not have the cross brace
The saddle was also a one year only feature, finished in a suede-like material and secured with chromed buttons. The original foam was a very high density red foam and the stamping on the seat pan was again, a one year only pattern.
Likewise the early MK I grips originally as standard (per the 1968 T500 parts manual) were different, and were likely available as a 'touring grip' option for other models under part numbers 57110-15010 for the throttle and 57211-15010 for the left side. These were built up having an anti-vibration core covered in a sleeve. At the time of writing, good quality reproduction 'puffy' grips are available at this link, although they are all one piece, rather than being built up as the originals were. The 'normal' slim grips are also seen on later original unrestored MK I machines, and are listed in later parts manuals as standard fitting for the MK II through 'L' machines under part numbers 57110-15110 for the throttle and 57211-15110 on the left. The sales brochure for the MK II seems to show both styles fitted.
I puzzled over how to install the frame side cover cushion 09329-02001 as, for whatever reason, I expected it to fit the mounting slots of the side cover and of course it didn't. Having never seen one, I wasn't sure where it went ! Fritz in Perth had an original side cover with one still installed on it - now I know.
Also worth mentioning:
The MK I oil tank and left side cover are 'round' when compared to later models, and as well the left side cover is metal rather than plastic. The top photo to the right shows the MK I oil tank - you can click through to see examples for successive years.
Four types are shown - the very early style having a stem clamp and flattened rear housing, no stem clamp but with flattened rear housing, round back and no stem clamp, and then the ones commonly sold as NOS having long stems and incorrect wire routing.
The photo below is of the front signal from a 1969 T500-II. Notice that the back of the signal housing is flat, there is no stem clamp, and that the stem is quite short - about 1 inch long, excluding the threads.
A similar front signal, but with a rounded end. The stem is about the same length as the one having the flat end, and no stem clamp.
In the photos below, on the left is what is commonly sold as NOS and has a long stem - about 2.25 inches long - and no stem clamp. On the right is the correct signal for the early T500's having the short stem, stem clamp and flat end (photos courtesy of Torgeir in Norway).
Likewise for the rear signals - the photo on the lower left is of what is commonly sold as NOS and has the long 2.25 inch stem with the wire on the outside, the rear of housing is round, and there is no stem clamp. On the right is a photo of the correct rear signal for the early T500's with the wire threaded inside the stem, the external stem clamp and the locking sleeve nut which was unique to the very early versions.
