Build Your Own ComforTmax

As promised at Beaulieu, here are PDF versions of the plans used to make the current version of the ComforTmax. As I have an A3 printer at home, all the drawings are that size, so you may have to do something creative if your limit is A4. If anyone wants the (sorry, only 2D) CAD files in DXF or DWG format, please contact me at angib (at)

All these drawings, except the fuel tank, were made as guides to the guy who did the metalwork on my bike. They are not sufficiently detailed to give to someone to make the parts and they assume you have a Tmax in front of you to work from.

Cmax-General-1 and -2 show the general layout in solo and pillion positions, the seat frame and footboard additions, and the drawings overlaid over the patent illustrations.

Cmax-Tank is the 'standard' fuel tank used in the ComforTmax - it is narrow enough to fit the seat frame between the tank and frame tube. If I were doing it again, I would:
- move the fuel pickup pipe and vent fittings further back where they wouldn’t risk getting damaged;
- rotate the tank sender so that its wires came out backwards not forwards; and
- fit a guard (a vertical flat bar) so that the seat frame crossbar can’t hit the fittings on the tank.

Cmax-Solo-Tank is an alternative bigger tank for bikes which do not have a pillion provision and so the tank fills the space between the frame rails.

Cmax-Footboards show the metalwork of the footboards. Several notes on these:
- Plenty of people would like them further forward but if moved forwards the individual footboards would have to also be moved apart to ensure wheel/mudguard clearance.
- It was intended that a brace would be fitted from the frame to the forward end of the fixed bracket under the back end of the footboards, to make these stiffer laterally. This was never done, but the footboards don’t have any noticeable flex, so they were probably superfluous.
- The footboards would feel more secure in use if it were angled slightly inward (ie, outer edge moved backwards) and the horizontal sections were shaped as gutters to hold the rider’s heels - either the side could be raised to give more cornering clearance or a bit more legroom provided.
- It may be obvious, but worth pointing out, that the footboards need to be detachable for major engine work. Removing the front wheel, the spark plugs or the carbs is perfectly easy with the footboards in place but doing the valve clearances or a top-end overhaul would make it worth removing the footboards.

Cmax-Seat-Frame shows how the seatback and tailbox are supported and moved between solo and pillion positions. I cannot say that the idea of using a sliding arrangement was the best solution, but it was the only one I could see that would work and fit in the space available – it would be easy to think of transport mechanisms that reduced the fuel tank to 5 litre!

The seat frame consists of a ‘fixed’ frame that is the inside member and a sliding frame that is the outside member of the slides. The ‘fixed’ frame is hinged on a frame tube at its front and has a crossbar at the back that uses the existing Tmax seat latches. The two parts of the sliding frame are joined by the seatbar, on which the seatback sits, and by a second flat bar crossbar not shown in the drawing. The sliding members on the ComforTmax are just square hollow sections, about 20x20 and 15x15, that fit each other fairly well.

Some pictures of the metalwork can be seen here.

Cmax-Tank.pdf100.48 KB
Cmax-Footboard.pdf192.56 KB
Cmax-Seat-Frame.pdf166.54 KB
Cmax-Solo-Tank.pdf179.36 KB
Cmax-General-1.pdf272.01 KB
Cmax-General-2.pdf377.17 KB