Front forks 79 kz650

I just bought my kz650 (first bike) and it could use a fork seal. I am wondering what parts I would need to this and how hard it is to do at home

You can do the job at home, but you MUST first buy a Kawasaki Service Manual!! They are usually available on eBay; be sure to get one for your bike's exact year and model because there are differences between the various KZ650 models. You will not regret buying the manual; not just for this task but for everything you do on the bike. Without it you run the risk of breaking stuff, or even worse, of setting up an unsafe riding condition. Even very simple tasks, such as mounting the front wheel, are often screwed up because folks don't have or were too lazy to read the manual. Ed

In addition to the fsm, a high quality (not made in China) torque wrench is important. You will also need a way to measure the oil level. I use a home made device consisting if a brass rod and an adjustable clamp. Proper metric wrenches and JIS (not Phillips) screwdrivers are also needed. 650Ed has posted a tutorial on how to modify a Phillips screwdriver if you would rather go that route. You will also need a way to support the front of the motorcycle while you are working. Two large eye bolts tied into the ceiling joists (not just the drywall!) and a cople of strong tie down straps will do it well. You may also be able to use a small hydraulic jack under the engine, depending on the exhaust system.

Tools that are not absolutely necessary, but will make the job easier, are----
Small pneumatic wrench
Bench vice with soft jaw inserts
Parts washer big enough for the lower fork tube (this is a bit of a luxury, but a nice addition to the garage)
Towels- I like the Scott paper shop towels for most jobs
A drain pan for the old oil

It can seem intimidating, but if you familiarize yourself with the procedure first, and have everything you need on hand, it is perfectly doable at home. If you are uncertain about any of it, or get hung up somewhere, there are plenty of experienced folk around here who can help.

Happy wrenching.

Several years ago I replaced the steering stem bearings in my KZ650 with tapered roller bearings. I found this to be a vast improvement over the original individual ball type bearings which had suffered dimpling caused by brinelling over the years. At the same time, for aesthetic reasons I replaced the lower fork legs with new old stock ones, and of course installed new fork seals.

To do this work I had to remove the front forks. I did the work in my basement during the winter. I laid a 4’ x 8’ sheet of 7/8” hardboard on the floor and parked the bike on it. This was to protect the basement carpet from possible stains, and it also enabled me to very securely anchor the rear of the bike while the front forks were removed. With the bike on the center stand, I put a small bottle jack under the front of the engine with a piece of wood between the jack piston and the oil pan to protect the oil pan. I jacked up the front of the bike until the rear wheel came in contact with the hardboard. Then I ran a cargo strap through the swing arm, attached the “S” hooks on the ends of the strap to the edge of the hardboard, and took the slack out of the strap. After removing the front forks I could have removed the jack and the bike would not have leaned forward, but I left the jack in place since it was not in the way of my work. That strap made the bike very secure. You may want to use this same method when you remove your forks.

Also, you may want to consider replacing the steering stem bearings using tapered roller bearing while you have the forks off the bike.

Here’s picture of the bottle jack under the engine. Unfortunately I didn’t have the presence of mind to take a picture of the strap arrangement. Ed

Ed, is that cross brace stock?
Steve

Yes, The frame has never been modified. Ed

Luckily the fsm came with the bike. Good to hear this job is do-able at home. One other likely dumb question...when starting and running the bike should the petcock be set to "on" or "pri"?

The 79 SR should have a vacuum fuel petcock.

ON & RES = when the engine is running, engine vacuum actuates a diaphragm assy to allow fuel to flow by gravity;
....................when the engine is off, a spring returns the diaphragm to the off position, stopping the flow of fuel.
PRI = bypasses the diaphragm assy, allowing fuel to flow by gravity --- engine running or engine off.

ON = normal position when riding the bike
RES = reserve --- switch to reserve when fuel level gets low, then find a service station within 20 miles or sooner or ASAP.
PRI = prime --- use pri to prime or fill the carburetors. I use prime briefly before attempting to start the motorcycle, to make sure the fuel level in the carburetors is sufficient.

Martin,
I am curious about the operation of the vacuum petcock. When it is set to the Prime position is the petcock drawing fuel from the normal (Run) intake tube inside the tank or from the reserve tube? This would be an issue for anyone who leaves the petcock in the Prime position because they have a malfunctioning diaphragm. Ed

From the reserve orifice on my 650-CSR --- which kinda makes sense. Otherwise, how could the carbs be primed if the fuel level is too low for the "ON" pickup tube.

Thanks. Ed