Tune up.

So I need the experience, I'd like to try doing a full tune up or service or however you might call it.

My bike is a 1983 KZ750 H4 Ltd.

Approx. 20,000 miles.


I have two manuals ill be using to keep things somewhat organized, but I'd like some advice from you guys.


Im currently running a high ratio on final drive for better acceleration that I plan on dropping to stock levels. Before I raised the ratio the bike topped at 8k rpm full throttle. No idea on the speed just know the Speedo was bouncing on 85mph.

As of now I am at 9.5k at 85mph. I've had a few of you explain the bad possibilities in that area.



I believe this bike has a lot of potential, I just need to know where to start.

And if you bear with me I will have my baby running the way she deserves.

9,500 rpm at 85 mph doesn't make sense to me. You may be going significantly faster than 85 mph, but cannot tell because that's where the speedometer tops out. Given that strong possibility, you need to establish a baseline for the current setup.

Here's where I suggest you start - bring the bike up to 40 mph in top gear. KZ speedometers are famously inaccurate, so you may want to have someone in a modern car pace along side you and signal when you both are at 40 mph. Once you are at that speed, look closely at your tachometer to see what rpm the engine is turning. If your engine really is spinning at 9,500 rpm at 80 mph (doubtful) it will show about 4475 rpm at 40 mph.

Try that and let us know the results. Ed

Tuneup: valve clearance check (get a new gasket beforehand) & compression check.
New spark plugs & spark plug wires (replace if old).
Consider getting new ignition coils, if the old stock coils are still being used.
Lubricate the timing advancer (new pulsing coil gasket).
Drain & clean the fuel tank and clean/check the petcock & screen. Fresh fuel.
Install new fuel line & in-line filter.
New air filter & clean out the airbox if necessary.
Synchronize the carbs. Maybe clean/check the carburetors.
Check/lubricate/adjust the throttle & clutch cables.
Engine oil & filter. Brake fluid. Fork oil.
Check the battery & tires.

In which gear? Also I believe the rpms are only that high because of the current rear sprocket.

We had snow last night so I can't check it today but ill get back with you when I have.

whirlwind598 wrote: In which gear? Also I believe the rpms are only that high because of the current rear sprocket.

Top gear = 5th gear.

Thought so, will do soon as it dries.

Before I forget do you have a brand of fork seals you'd recommend?

Genuine Kawasaki. As long as your fork tubes are not pitted, and if you give them a quick wipe now and then to keep them clean, the seals will last for decades. My originals still did not leak at all after 30 years when I replaced the lower (outer) fork tubes 8 years ago because the original tubes were getting ugly. I put new old stock Kawasaki seals in the new tubes then, and they do not leak at all either. Ed

OEM or K&L fork seals. K&L parts are made in Japan & oem quality. I''ve used various K&L
parts & kits w no issues whatsoever. Unfortunately, Z1Enterprises no longer carries them, but K&S fork seals instead -- I have no idea if those are any good or where they're made (chinese junk???).

I think BikeMaster fork seals are now made in Japan, but I don't know if they're comparable to oem.

Fork oil: the manual specifies 10W for my 650, but next time I'll use Bel-Ray 15W.

I have found that the Kawasaki Service Manuals seem to be inconsistent when it comes to what weight fork oil to use. My manuals show 10w; 15w; and 10w20 depending on which manual I read.

I believe you will find the 15w Bel Ray fork oil will work very well. I've been using it in my KZ650 since day one and found it works great for me. Ed

Sounds good, mine are definitely shot, I can bottom them out by pushing down...

Gotta replace the front brake pads, it's slightly embarrassing when I come to a squealing stop lol, the rotor/disc seems find though.