Brand New Rider and New Owner of 1983 KZ750 LTD

Hello All – I am the new owner of a 1983 KZ750 4-cylinder LTD. I have never had a bike, but I thought it would be fun to have a little cruiser for riding to work and back, possibly take on a small trip to the west side of the state to visit some friends.

My big question before I get into details about myself – do any veterans have a good website or reading material for someone who is just starting to come into modifying bikes? I know a ton about cars through schooling and working on them, so the actual functions of the bike I understand. My issues are all the little things that aren’t usually explained because they can be considered common knowledge to riders who have been around motorcycles for a while. I am not looking for the answers to my questions here, but for example – I want to lower my bike a little bit, and I have read on here that a few people have done 883 Sportster Rear shocks, or shocks from a Honda Shadow 550. How did people find out these shocks work? Are most rear shocks the same mounting bolt size and spring OD, just different lengths and spring rates? While this lowers the bike, is it the right way to do it for ride quality and handling? For a car, you can lower a car by cutting springs, new lowering springs, new shock/spring packages, redesigning the entire suspension, etc. Some are bad ideas, and some are okay if done right considering the intentions of the car. I guess I don’t understand what is a good idea and a bad idea with motorcycles, and just because I found someone that says it can be done, doesn’t mean it should be done… Just another example would be how I would go about looking for a newer, lighter set of wheels. Aside from perusing the forum, I don’t know where to start regarding wheel width, axle size (?), hub width (if that is even what you would call it), if the brakes will bolt up to the wheels, things like that. Can I change the width a little without changing the frame? Do most bikes have the same axle size, or are there a two or three that are really common? I feel like such a newb when I search for this stuff because sometimes I don’t even know where to begin or my searches come up weak because I am not using the right terminology or searching for the right questions. There are so many smart guys out there that know this stuff like the back of their hand, but it all seems so foreign to me and a little overwhelming to try and pick up to really understand if what I am doing to the bike is going to make it actually better. That’s why I was hoping there is a good read for a newb like me that would get into a little bit more details on how to approach some of the more common modifications.

Anyway, a little about myself – I am pretty big into cars and racing, mostly autocross for now since I sold my fun car. I have been working on cars since I was 16 (am 27 now), and in the past few years have really started to get into fabrication. My current project is a 1994 S10 that I am building into road race truck, and fabricating everything from the engine mounts, cross members, and suspension, all the way to the fire wall, floor pans, and roll cage all on my own. Pretty much the exterior skin and frame rails will be utilized, a 5.3 truck LS (for now), Muncie 4-speed, Ford 8.8, and 2010 Camaro SS brembo brakes. Everything else will be fabricated. From everything I have read, the best way to get into fabrication is just by doing it. Being an engineer helps, and I have taken welding classes at my local CC, but I have learned a ton just from diving in.

I have always thought motorcycles were cool, and I really liked the older style bikes, so I had been wanting to build a chopper or a café racer or something. When I asked my good friend if we wanted to sell his KZ750 that he picked up for 1000 bucks a few years ago, he said I could just have it (I help him out with a lot of home improvement projects and car stuff). It had started to misfire, he dropped it a couple times (this was the bike he learned how to ride on), and as he was starting to teach his wife how to ride in the driveway, she forgot where the brake was (?) and drove it into the garage. So the bike was not in good condition when he bought it, and now it’s in even worse shape. On top of that, he started taking the engine apart, not quite knowing what he was doing, so the bike was torn apart when I took it over.

I put the clutch cover back on with a new gasket (buddy removed it for some reason), drained the oil, put a new filter in it and new oil, and I am now starting to work on the misfire. I swapped out the plugs real quick and that didn’t fix it, but I have assumed it is the plug wires because I think they are honestly the original wires. I am still trying to figure out how to get new wires – I bought the Dyna 8mm suppressor core wires after doing some searching on here and another forum, but I can’t figure out how to hook them up to the coils (the wires are set up to be a push on style end where the stock coils have the screw style). My next step is to pick up a new set of wires – I have read that NGK (?) sells universal 7mm wires with screw caps at O’Reilly’s, so I am going to stop by there on my way home and see if I can find what I am looking for.

I have my motorcycle class at the end of April, so I am very excited to get the bike running and ready to start riding come May. My buddy wants me to get it running again so he can ride it a few more times before I officially take it, so there is that too .

Anyway, sorry for the long post, but I have appreciated reading all the information on this site so far, you guys have already helped me out a lot!!

Welcome aboard!

Here are some tips that you may find helpful:

Many newbies and not so newbies run into or issues with their bikes which could be easily avoided with a little preparation or information. Here are a couple recommendations that I hope you will find useful.

Before riding your KZ you should take a little time to become familiar with it. Simple things like checking the oil, tire pressures, etc. are explained in the Kawasaki Owner's Manual. If you bike didn't come with one (they normally are in a little holder on the bottom of the seat) you can usually find one on eBay - be sure to get one for your exact year/model.


MANUAL

You really should consider buying the Kawasaki Factory Service Manual for your bike. The factory service manual provides instructions on the various maintenance procedures and schedules for your bike, procedures for diagnosing problems, proper torque values for the various fasteners (VERY IMPORTANT), 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.

The manuals usually are readily available for most models on eBay and other sources; but 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. If you have trouble finding one for your model ask us to help.


TOOLS

WARNING! Do not even try to use Phillips screwdrivers on the Kawasaki cross head screws. Despite their appearance they are not Phillips screws. They are Japanese Industrial Standard (JIS) screws. The tips of Phillips screwdrivers are too long & pointed to allow the 4 blades of the screwdriver to properly engage the screws, so when you apply force the screw head slots will deform and look like crap. The fact is that Phillips screws were deliberately designed to have the screwdriver bit "cam out." This was done to prevent production line assembly from over-tightening, stripping, or breaking the screws. JIS screws do not have this problem. A proper fitting JIS bit can tighten a JIS screw to and beyond the torque spec without camming out. Here's the good news - you can easily modify standard Phillips screwdriver tips to fit the JIS screws.

I have ground down the tips of DeWalt #2 and DeWalt #3 Phillips to make them fit JIS screws. The large crosshead screws on the cases take modified #3 bits (or genuine #3 JIS bits). To modify the DeWalt bits you need to grind the very tip a little, then test fit, then grind a little more and test fit, etc. until the bit no longer "rocks" back and forth in the screwhead. Picture 1 below shows how a DeWalt #3 bit fits the case screws of my KZ650 after being ground properly. The #2 DeWalt bits can be modified the same way to fit smaller JIS screws. Pictures 2 and 3 below shows DeWalt #2 and #3 modified bits.

I did find a place that sells authentic JIS bits. They don't list the #3 bit, but if you contact them they can provide the #3 JIS bits even though they are not listed on the website. These folks were very easy to work with, and the authentic bits do work great. Here's their site:

www.rjrcooltools.com/shop_item_detail.cfm?subcat_ID=89

Pictures 4 & 5 below show a comparison between my home made modified bits with the authentic JIS bits.

PICTURE 1

PICTURE 2

PICTURE 3

PICTURE 4

PICTURE 5

Before reaching for that wrench or ratchet consider the following. The bolts are steel, but your engine and front forks are aluminum. 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 grief, time, and money. Tightening fasteners properly requires torque wrenches. 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. You will need a torque wrench calibrated in INCH POUNDS for many of the bolts. You will also need a torque wrench calibrated in FOOT POUNDS for the larger bolts. Don't try to use the foot pounds wrench on the smaller bolts as it will not be sensitive enough at low torque settings to provide accurate torque. 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. The Kawasaki Service Manual will list the various torque specs for the bolts. I suggest you get the manual before buying the torque wrenches so you can decide which wrenches best meet the torque specs.

Consider buying a can of Kroil penetrating oil and use it to soak stubborn fasteners for a couple days before trying to loosen them. Remember, the original screws and bolts were installed on your bike when Jimmy Carter was President, so many of them may be hard to remove. Kroil can be bought online, at guns shows, and at some other venues.


MOTOR OIL
The ingredients in oils have changed over the years. For example, today's Castrol GTX oil (and pretty much all other AUTOMOBILE oil) is not the same as it was in the 1980's. Back then it worked great in KZ bikes. But, things have changed. Early AUTOMOBILE oils contained zinc phosphorus compounds (ZDDP) to protect engine components from metal to metal contact. This was good for engines, but it was found to be destructive to catalytic converters. Consequently, in AUTOMOBILE oils ZDDP was virtually eliminated and replaced with different chemistry generically referred to as "Friction Modifiers." These work fine and offer good protection for normal AUTOMOBILE engines. However, today's AUTOMOBILE oil "Friction Modifiers" are destructive to wet clutches. KZ bikes (and many other brands) have wet clutches. As a result of these oil chemistry changes a distinction needed to be made between those oils which are suitable for wet clutches and those which are not. That distinction was documented by the Japanese Engine Oil Standards Implementation Panel (JASO). JASO developed a number of different oil specifications for different applications. The specifications that apply to 4 stroke motorcycles fall under the "4T Specifications." Within the 4T specifications the JASO MA class oils are specifically formulated for 4 stroke motorcycles with wet clutches.

There are synthetic, semi-synthetic, and non-synthetic oils that meet the JASO-MA standard and any of them will work ok. However, using oils that are not designated as meeting the JASO-MA standard is destructive to KZ clutches.

Good luck with your bike. Ed

Whew, welcome. :lol:
Steve

Welcome Aboard, 7-fiddy
Pete

here's some general stuff that might be useful.

Assuming the motorcycle is a 750-H4 Ltd chain drive (there was also an 83 750-F1 Ltd shaft).
the most similar models are the 80-83 KZ750H Ltds. then the 750E standard models. also the 81-83 650-csr.
the Ltd & csr frames are very similar & they share a number of parts. same ignition system & charging system.
the 750 Twins are completely different in most respects.

Partzilla -->> oem parts -->> Kawasaki -->> motorcycle parts -->> choose a year then pick a model.
the site is probably the easiest/fastest to use for comparing stuff. it's not perfect, though. there are other places.

Manual. 750Turbo.com. 1980-84 KZ750-4 1983-85 ZX750 pdf manual. good pdf scans. 750turbo.com --- Index
there is a complete manual, plus sections of the manual divided into 15-20 pdfs but those may be incomplete.

Wiring diagrams. Here's a site w a pdf manual & wiring diagrams. mbsween. bike-night. KZ750L3 .
Scroll down & click "The Bible" link. the manual is of lower quality than the one available at the Turbo site.
Note: some of the wiring diagrams are mislabeled in the links: the 1981 Ltd is an H2, the 82 is an H3, & the 83 is an H4.

Work on getting the bike running safely and reliably before you start to worry about modding the thing. There are about a million thing to do to a 33 year old motorcycle so start by going down the list of maintenance items in the factory Kawasaki service manual. Things like valve adjustment, carb rebuild, clean out the brake system, etc will keep you busy for a LONG time.

Lowering the back end will make the bike steer like a truck. I'd avoid that. Lighter wheels won't do crap for the bike either other than lighten your wallet. I don't even think there are wheels you can swap on without heavy mods.

Pics, need pics. :woohoo:
Steve

Thank you guys for the information! I feel like the information that was shared by Martin_CSR and 650ed is really useful for a lot of people - has someone ever put together a sticky for new owners with a lot of that information plus any other helpful hints for someone who has never owned a KZ?

As for some pictures - these are from last year after I talked to him about wanting the bike. I basically let it sit all winter in his garage because i had no room for it and I was busy working on my S10. Broken headlight, missing front fender, dented gas tank, broken engine cover on the right side, missing grips... It has probably seen some better days.