Japauto
The first, and main, projekt was to build a replica of the victorious JAPAUTO who won the 1973 Bol D'or in France. Although at first the goal was to build a replica of a Endurance bike from the dutch VOS-OSS team who, almost, won the 24 hours of OSS in 1973. Both of these bikes were based on the CB750. First I had to find a 'donor' bike to start with. Found one trough my brother in law who knew a guy with a scrap bike. Started to dissamble it and make up my mind of which direction I would go. My main objective was to build a bike that would resemble, but would not be a 100% copy. I feel you have to put something in it, that comes from yourself. But the bike would be build like they where build back in the day!
The JAPAUTO
One of the greatest problems I had, was that during the build I was temped towards other examples of bikes that I thought were very interesting. Bikes like the CR750 that Morio Sumiya rode in Daytona or the Yoshimura bikes from 1970/1971.
But luckely I managed to stay with the JAPAUTO as an example. To get parts for the build I used a lot of time on Ebay. Managed to find some interesting parts, like a genuine JAPAUTO throttle. Found period RONAL and SMAC wheels and managed to find the man who bought the last stock of parts from RONAL to purchase some, NOS, parts. Through the french, of course, 1000VX Club de France I bought a beautiful seat and front fender. One very important source of new,and used, parts is my very good friend Johan Spaan, owner and founder of www.Fourdeel.com
Brakes are the most important part on a bike, so I went for completely new, but period, parts from GRIMECA and LOCKHEED.
A lot of parts are handmade by myself like, the 4 into 1 exhaust, the oiltank, the swingarm, the reinforcements of the frame, all the mounting brackets and footrests etc.
Also kits to improve on the lack of damping and spring pre-load adjustment, of the original front forks, have been developed and are run both on the street and on the closed circuits.
The end result:
Mounting the JAPAUTO endurance fairing and changed exhaust
Most of these parts can be purchased through the shop on this site.
One of my main goals is to keep this beautiful hobby of ours payable. Therefor my choice is to try not to invent the wheel again, but to use what is already there. One of the objects that has had a lot of comment was the frame of the CB750. In my opinion the problem is not in the frame, but in the way the engine is held by the frame. For this reason I have made the stronger engine mount kits. I also have made the engine mount bolts from SS material which also has more strength. These cam be made in the OEM length or can be made in almost any length if there are rearsets involved.
One issue with the frame is that, if there is some work to be done at the cylinderhead, the engine has to be removed from the frame.
There is a old solution, used a lot in the 70's, which has been brought back to life. In order not having to remove the engine because of lack of room, create this room by making a part of the frame removable.
My next projekt is to modify a frame with usable strengthening, removable toprails and build a bike from that.
Frame rail kit is mounted, several special parts are in the process of manufactering. At this moment I am working on a set of swingarms, one for a customer and one for the new bike. The bearings are tappered bearings or the bronze bushings.
Last update:
I use laced Aluminium Excal rims, with the, slightly modified, original brakes. Rear brake operation converted to cable.
Tyres are, like the original, Dunlop K81 TT100 4.25/85x18 in the rear and 4.10x18 in front.
Front will be changed to the more modern B45 from Bridgestone.
The bike as shown at the 1st Dutch Classic Superbike Meeting on the 13th and 14th of June 2009
Latest in battery technology mounted in the seat off the JAPAUTO, very tight and no ugly big, heavy battery in sight!
The 'new' engine:
For now I have been using a, almost, standard engine. Though running very well it needs some extra horse power. There are 2 options, one is to tune this engine or two build a new one. I haven chosen the latter, and have started to build a fresh engine with a lot of extra power, but it needs to stay in one piece.
I started with a F1 engine with cases that a have no damage signs. I had the cylinder bored to a bore of 65.5 m/m to get a healhty 850cc. I use a Cycle-X 850 kit from the USA. To keep the engine oiltide I use the HD studs from APE, both cylinder and main studs.
The crank will loose some 2,5 kg and I will use a longer duration and higher lift camshaft. The HD camchain comes from Tsubaki and the camchaintensioner from M3 (USA). To keep the valve train in one piece, I made some reinforcements to the camcover.
One of the latest projects is the development of a dry clutch for the CB750! This will shake the CB750 community, because this is never been done!
This is developed by my friends Piet van Leeuwen and his son Maarten and voxonda.com.
This clutch will be on sale after the trailruns have been succesfully completed.
