Welcome aboard!
If it were mine I would replace all the fluids (oil, fork oil, brake fluid), BUT first, buy a genuine Kawasaki factory service manual for your specific year and model. These are readily available for most models on eBay and other sources; but again, be sure to get one that has your specific year and model in it as there are differences between the various KZ650 models. I do not recommend Clymers, Haynes, or other aftermarket manuals as I have seen instances where they provide inaccurate advice. You may decide to use those to supplement the factory manual, but in my opinion they are not a suitable substitute. The factory service manual provides instructions on the various preventive maintenance procedures and schedules for your bike, procedures for diagnosing problems, proper torque values for the various fasteners, and insight into how each system on your bike works even if you are not repairing that system. Studying the manual before you attempt performing service on your bike will impart an understanding of the system you are working on which will increase the odds of success.
After gaining a basic understanding of the maintenance you wish to perform you will need tools. Kawasaki uses numerous steel screws and bolts some of which are threaded into the aluminum engine. The bolts are much tougher than the aluminum and if over tightened will strip the aluminum threads. Although these can be repaired, preventing damage by applying proper torque will save you time and money. Various vendors, including Snap-on, CDI, Sears, etc., market torque wrenches. The two most popular types are the bar type and micrometer type. Either will work, but the micrometer type is a bit easier to use, especially if you are tightening several fasteners with the same torque – such as cylinder head covers. I have found that it takes 2 different scale torque wrenches to properly torque most if not all the fasteners on the KZ650. There are many fasteners that require low torque. These include such things as 6mm oil pan bolts, cylinder head cover bolts, etc. for which the torque in 61-78 inch pounds. These low torque bolts require a wrench that is accurate at low settings and this wrench should be graduated in inch pounds. In addition, there are numerous high torque fasteners such as the front axle nuts (51 – 65 foot pounds) or swing arm pivot shaft nuts (58 – 87 foot pounds). These require a wrench that is accurate at higher settings; this wrench should be graduated in foot pounds. Using the proper torque wrenches to correctly tighten fasteners will help prevent damage and contribute to a safe bike. Also, the "Phillips" screws are not Phillips; they are Japanese Industrial Standard (JIS). Elsewhere on this site is described an easy way to make screwdriver tips fit properly, using a Phillips screwdriver tip will damage the screwheads. Let me know if you cannot find the reference.
One thing difficult to overcome is the urge to rush. In the long run rushing will cause you to take longer to fix a problem or perform a procedure compared to taking your time and carefully following the instructions provided in the manual and on this site. The key here is to do things right the first time. That will give you a safer bike, save you time and money, and make working on your bike more rewarding. Good luck and keep asking questions. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
