More for you, save it to your computer but I also recommend
printing out a copy and putting it in a 3 ring binder for shop referral.
https://ia800204.us.archive.org/14/...ice-manual/yamahavmaxvmx12-service-manual.pdf
The first 64 pp. are annual updates with data which may or may not refer to your year. 1985-'89 have an analog engine management system, using
two pick-up coils for ignition timing while 1990-'07 use a digital ignition box with a
single pick-up coil. The 1985-1992 bikes have a single pair opposed piston, two caliper front brake system, and the front rotors are smaller in diameter. The fork downtubes are 40 mm as are the sliders and triple trees, of course. The 1993-'07 bikes are 298 mm rotors, and front two opposed pistons, each caliper (two calipers) and 43 mm downtubes, sliders, and triple trees. Don't forget to check the air in the forks at the schrader valves, 5-~15 psi, unless you have Progressive Suspension fork springs, they say to not use air pressure in the forks.
You can improve the 40 mm forks bikes by swapping out the 40 mm front end for a 43 mm front end, you can re-use the wheel, but the rotors, calipers, front wheel brace/fender mount; downtubes, sliders, & triple trees will need to be replaced with the pieces from a 1993-'07 bike. The front brake caliper stays the same. Add to that Progressive Suspension fork springs, or Race-Tech fork springs, and Race-Tech Cartridge Emulators (C.E.), which change the damping from the fork internal rods to the C.E.'s. Setting the pre-load and adjusting the C.E.'s for your weight and riding style are necessary to get the best use out of the components. RICOR is another company which also uses pieces similar to the C.E.'s for damping. There are many threads on here about these pieces, so look at them for more info, and riders' experiences.
Going to an USD fork is an expensive thing to do, and you need to extend the downtubes buying custom ones or using 'slugs' to extend the factory downtubes. Why? The sportbike downtubes are inches shorter than the OEM VMax downtubes. There are triple trees that can be used with the factory USD forks you choose to use, but they are also expensive. If you absolutely have to have them just look on ebay, there are several suppliers. I checked exactrep, a British supplier of many custom parts, but it looks like they have stopped carrying the USD fork pieces.
Here's one place which does have a selection of Generation 1 (1985-2007) VMax USD fork triple trees. Bear in-mind that you need to ensure that the calipers, rotors, and brake lines, and the speedo drive and front wheel have to be matching the front end you choose to use.
https://www.ebay.com/itm/162646972426
The best ways to improve brake handling on a budget are to replace the brake pads with HH rated brake pads, and to replace the brake rubber lines with stainless steel (SS) lines. Also, purge the brake system of
all the old fluid, and replace it with fresh DOT 4 brake fluid. Doing that using a reverse-flush method is what I prefer, it's a fast, easy way to bleed/replace the clutch fluid. Using some teflon tape on the brake caliper or clutch slave cylinder bleeder nipple helps to keep the fluid flowing into the hydraulic system, and not 'peeing-out' of the bleeder, past its threads. Here's a thread on reverse bleeding, repair/replacement of the clutch slave cylinder, and how to make an easy to source reverse bleeder tool:
https://www.vmaxforum.net/threads/clutch-slave-cylinder-replacement.45011/
Another resource for electrical diagrams, yearly Generation 1 designations, differences among the years of production and the factory shop manual (again):
https://www.vmaxforum.net/threads/vmx12-factory-service-manual.52788/
All that should keep you busy awhile, and servicing the brakes is something that a bike which can accelerate to 140 mph in about a half-mile should have done periodically.
) and I have a big head. Enough about me.....I'm just not that interesting.
