1982 KZ750 Twin CSR Rebuild

This is my first motorcycle resurrection, but I have working on cars for almost 30 years as a shade tree mechanic, so I will be asking alot of questions as I go along. The back story is that the bike is a one owner with 10K original miles on it. It sat up for a long time but appears to be keep in a garage or somewhere with some climate control as most of the rubber bits are still soft and springy.The bike was 99% complete , just missing the tailights. It even has a sissy bar on the back.

So far the tank has been treated and sealed, new tires, a new front master cylinder. , new rear brake shoes and a new battery. If anyone needs a battery I got a AGM battery with 210 CCA from batterymart.com for $45 shipped that fits perfectly.

Link for Battery

Some pictures of the bike

Ok here are some questions to start...

I put on aftermarket taillights and now the blinkers do not flash, they come on but do not blink. The taillights came with a 10 watt bulb, is this to small a wattage or would it be a bad relay?

Here is a couple of videos of the first firing of the bike after an oil change and fresh gas in the carbs:

Video 1 - Very first firing before it warmed up (CLICK HERE)

Video 2 - After it started warming up (CLICK HERE)

It started to idle with half choke after getting warmed up some but it would not go over 4000 rpm. Do I need to rebuild the carbs or just try and clean them out?


This is a picture f the frame right above the carbs and airbox. Is there a rubber piece that goes into this slot for the rear of the tank to rest on? If there is what is it called.

Yes there is a rubber grommet that fits in that hole to friction fit the rear of the tank. Not sure you'll find a replacement. I had an old bike that lost one and I ended up making my own using a small chunk of baler belt, cut a hole in it smaller than the oval in the steel mount point, and pop riveted it to the frame. Worked very slick.

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ric812 wrote: .............. Is there a rubber piece that goes into this slot for the rear of the tank to rest on? If there is what is it called.

Yes. It is called a "rubber fuel damper" and is Kawasaki part number 92075-295 (see www.powersportswarehouse.com/p/Kawasaki#...50-M1-1982/080102F-6 ). They are readily available on eBay; just do a search for that part number. The prices have a wide range; here are just two of a half dozen of them that are there today. Ed

The tail/brake light bulbs are dual filament. According to Partzilla, the tail light bulbs should be 27-8 or 27-5 watt bulbs. That is, 27 watts for the brake light filament, and either 5 or 8 watts for the tail light filament.

I can't tell for sure but if those rear blinkers are LED you probably just need to change the flasher to the electronic style. They are common at the auto parts store. Good luck on the bike. Looks like it's worth saving with some TLC.

They are regular taillight nulds not led. I found a broken orange wire going into the blinker and changed to an electronic flasher.

Update time.
I replaced the BS38 carbs with a set of BS34 I bought on EBAY that were listed as from a 1982 KZ750 CSR Twin. I have soaked them and replaced some orings on the enrichment screw and pilot jet screw. I could not get anything else apart.. Replaced the pilot jet rubber plug. There are new carb holders and the rubber elbows from the airbox to the carbs. I reinstalled them and with the pilot screw set to 1 1/2 turns out I ca get it to idle somewhat smooth around 1200 - 1500 but when applying any throttle it is slow increasing RPMs and if I apply it to fast I am getting some popping but not every time. When applying the choke it will rev up to about 2000 rpm. It will not stay idling more then 2 or 3 minutes before it dies. It take about 2 or 3 kicks to fire even when it is warm (starter does not currently work). It is not running smooth at all and I am pulling my hair out trying to figure it out. PLEASE HELP! It has new plugs NGK BE6S. Any advice on what to start. I have adjusted the pilot screw from 1 turn to 2 1/2 turns out with out much change in the running. I have attached a couple of pictures of the plugs after the last run with the pilot screw at 1 1/2 turns out and run for about 10 minutes.

just soaking the carbs likely isn't enough to clean them out if they are crusty. You need to pull each jet and make sure the holes are all clean and then spray cleaner through every circuit. Also if you soaked them with the diaphragms in, depending on what you soaked them in, you could have damaged the diaphragms which would explain mid-range throttle issues. if there are any holes in the diaphragms they will not run right. i think you need to do a thorough clean before you start trouble shooting anything else.

I had them completely apart and soaking in pinsol diluted 50% . Diaphrams removed mains jets removed, enrichment valves out, pilot screws removed . The diaphrams were soaked in alcohol with wintergreen oil. I confirmed that they do not have holes. Then after soaking I blew everything out with carb cleaner. But I may have found part of the problem. The ignition points or at least what would be points if it was not electronic, are.rusted completely shut. Here is some pictures.



How do I remove this and do I have to replace the whole thing or can I clean it and just replace the springs?

The liquid at the bottom is PB Blaster.

well it sounds like you cleaned the carbs good enough, the way you worded it the first time sounded much different.

That is the ignition advancer. it advances the timing as the RPM climbs, it very well could be the source of your problems. You hold the 17mm nut on the end and back out the smaller bolt and them the whole assembly comes off. I would soak it in acid to remove the rust. you need to inspect the advancer cam and make sure the rust didn't damage it too bad, if it looks serviceable i would replace the springs and oil it before putting it back.

if you want a super cool ignition that completely replaces this, check out C5 ignitions. i just installed one on my 1980 750 twin and it starts up first kick.

Thank you for the information. Would you have a part # for the springs or an alternative part. All I can find is the complete assembly. When I opened it up the weights were completely frozen. So
I am assumimg that the timing was not advancing at all. It is good to know it may be serviceable.