The start of something beautiful

Well, here are some pictures and specs of my baby.

1981 Kawasaki KZ305 CSR

engine: 305cc

Maximum HP: 30 at 9000 RPM

Maximum torque: 2.5 kg-m at 7000 RPM

Carburetor: Keihin CV32 (2), constant velocity, diaphragm type

Clutch: Wet, multi-disk, manual 6 speed (1-N-2-3-4-5-6 (w/neutral finder)

Dry weight: 152 kg (335 lbs)

Fuel tank capacity: 10.5 liters (2.7 gallons)

Whats gone wrong:

This was my first bike so I was unable to take it for a test ride. I did however have the owner start it up and give it a few rev’s listening for any signs of trouble. Only problem I could see was a very high idle (6k RPM should be about 2k).

Turns out the bike wouldn’t go over 45mph!

  • So here’s what I did:
  • Removed and deep cleaned carb
  • Checked diaphragms for tears and ensured working correctly
  • Made sure floats were correct and float bowl sealed
  • Unscrewed all jets and cleaned (Pilot screw 1 3/4 out, Pilot jet all the way in, all others all the way in)
  • Added silicon seal around rubber boots connecting carb to ensure no air leaks
  • Removed petcock and cleaned, verify filter’s not clogged and seal is good
  • Tested fuel line for proper flow out of petcock and into carb
  • Installed new NGK D9EA plugs and gaped to .6mm
  • Checked plug wires and plugs for spark
  • Added brand new battery
  • Tested battery voltage while revving up to 3k RPM to verify charging system works
  • Soaked carb for 2 days in some good cleaner (removed all rubber parts first)

After all that I fire it up and were running great, going over 70mph with no issue and plenty of power left.

A few days later I go to fire her up and ……nothing won’t start. Battery tests fine so I check the plugs, weakest orange spark I have every seen (should be a bright blue) so now I am off to find a replacement set of coils.

Turning a frown upside down after the coils are replaced the bike will be good for many years to come, and I gain that certain sense of well being knowing that the original coils are now replaced and I don’t have to worry about them going out on a trip.

I would like to thank all the guys over at the Kawasaki Twin Owners Forum! Without them I doubt I would ever have had my bike running, everyone was very helpful and knowledgeable.

Update – October 4 2009

Started to strip apart the coils and re-wrap/build decided to look for some aftermarkets and found a set from a Yamaha that match for $30.00 on Ebay (beats the $300.00 from the dealer). Also decided to check the points and condensor and guess what, condensor faild on my Digital Mutli Meter (DMM) and the old fashion charge and arc test. Good thing there only $20.00 from the local dealer.

While checking the points gap I noticed the right had a huge gap and the left was in contact, so now I have to rent a strobe gun and adjust the timing and set the points gap. Glad I checked with new coils, condensor, and proper timing and points gab she’ll run like a top! Looks like the total cost will only be about $50-60 too.

I do still have an inkling one of the carb pasages is a bit clogged up but will look into that after the ignition system is all set.

Finally found a good copy of the manual for this puppy, that will save TONS of time looking up sepcs such as torq settings on the troublesome generator which you have to remove just to check the timing marks… (download available below)

Update – March 21 2010

Getting the bike ready for the riding season:

Well it’s been in the high 50’s even peaking into the 60’s around here for over a week so why would I ever be surprised that we had a snow storm roll in Saturday and blanket the area with the frosty goodness then retreat back to the 50’s and tomorrow high 60’s, I mean this is Michigan after all.

I made the most of the opportunity and started getting the bike ready for summer. Points were checked and gaped, coils tested and battery thrown in. New shiny spark plugs were added and the carb removed and cleaned again for good measure. So after all that and a fresh tank of gas she fired right up on the first try. However with an idle of 4k RPM with choke on and removing the choke kills the engine it sounded like a lawnmower about to explode. Adjusted the idle setting and checked for bindings and determined it must be the carb. After even more inspection and some help from the great guys over at the Kawasaki Twin Owners Forum it turns out the pilot jet (#35) on the right carb is missing the tiny hole in the bottom that allows air to pass through. Now when I say tiny hole I mean a thread couldn’t pass through this puppy. Only on trying to figure out how the carb worked and thinking WTF when seeing no hole under a magnifier did it dawn on me that this would be the cause of all the troubles. It really hit me when I contemplated all that has been done so far, and that only on backing out the pilot jet until it was loose did I finally get the speed back in the engine. One carb was not getting the proper air/fuel mix and fighting with the other while it tried to balance. Overall setting the points, plugs, coils, battery and cleaning and the carb did a world of difference so I am now confident that with the replacement of this one problem jet the bike will run like new.

I’m off to the local dealership to but a tiny piece of brass (pilot jet #35) for $12 and get this finished once and for all.

Update – May 12 2010

I went down to the dealer and got the pilot jet ($13) threw it in and…

Hmm won’t seem to turn over, solenoid clicks but no starter activity but a low (???) noise.

Just to check I try jumping it and …nothing. Hmm how about a bump start…YUP! barely had her down the road and hopped on threw it in first and BAM fired right up, ran like a champ. Looks like it’s on to replace the starter (rebuild kit) and perhaps the solenoid too.

Update – February 2012

Well it has been a crazy year I am back stateside now. Even though I have since parted with this bike I wanted to share what finally finished fixing this gem. Rather than the starter upon further deliberation I had replaced the solenoid and coils (as stated above) and the final fix was new points, yup that simple a new set of points I had overlooked through carelessness. When I find the time I will get a permanent fix for the link below some folks have reported difficulties and wordpress isn’t too happy about hosting such a large file. Don’t fret shouldn’t take too terribly long and as of now the download works for most.

Full PDF of Service Manual below: 64MB

Kawasaki Z250 79-82 & KZ305 81-82 Service Manual – To download right click and chose “save as” or “save link as” or else you will get an error


19 Responses to “Motorcycle”

  1. Thnak you very much Sir for the manual. Living in a 3rd world country it is very hard for me to acquire it otherwise.


  2. Happy to be of assistance Azzy!

  3. i hav an ’81 single cylinder csr250 – do u know if there is supposed to be a rubber plug over the pilot srew?

  4. Jesse – Pilot Jet or Pilot Screw?

    The Pilot Jet is inside the float bowl and has a rubber plug covering it.

    The Pilot Screw is on the outside of the carb and comes with a black plastic plug covering it which you can break off to make adjustments to. The plastic plug for the Pilot Screw is not needed. If you have made changes to your Pilot Screw accidently make certian to bring it back to factory setting of 1 3/4 turns out

    Check out the website under Owner Info > Parts Diagram to pull up the diagram list for your bike.

  5. How do you renove the seat on this bike?

    • The seat can be removed by inserting the ignition key into the lock on the left bottom side of the seat (on the frame just below the seat a little farther back than the middle – by left I mean your left as you sit on the bike facing forward). Turn the key to unlock the seat and lift up and back to remove.

      Also the small lock that holds the seat in place also has a little square hook that can be used to lock up a helmet strap.

  6. My nieghbor just gave me a 1982 cz305 with 4k miles on it. Doesnt run dead battery. I know nothing about this bike. Do you have a manual for this thing.

    • The manual is located right above the pictures right click on the link and chose save as


  7. Was given a Z250 twin without key, previosly registered to a friend in 95. Have not had it up and running and am wondering of my first step (apart from getting either locksmith or new ignition). Anyone able to advise?

  8. I downloaded the manual twice and when I tried to open it it said the document could not be opened because it is damaged. Has anything been done with the file? Thanks!

    • Just rechecked the file, all is well. Sounds like you may be downloading from a slow connection. Since the file is so large over a slower internet connection (or sometimes via wireless) the download can complete yet become corrupted and unable to open. I’ll see if I can compress the manual and make it small enough to download on a wider variety of connections.

  9. Really really REALLY appreciate you posting this, and updating it over time AND the DL link for the manual. Hopefully it’ll save me hours of grief in the future. I bought a CSR250 from a friend – really random, he decided to start chopping bikes, and this is one of the first ones he did. As soon as I saw he posted it on FB, I knew by the engine size it was a smaller frame and as soon as I contacted him he was like, “dude, get over here, it’ll be perfect for you”. And he was right. I’m a smaller guy so yeah, love it.

    He did a great job bobbin’ it, it looks like an old Triumph now, and people are seriously fooled on the age of the bike, but it’s definitely going to need some more TLC before it’s running exactly how I’d like. Your notes and comments on what you’ve had to fix, worked on, etc have really opened up ideas in my head about what to start looking at, and clearing up.

    Thank you – you made my Monday a happy one!

  10. Very informative thanks, I presume your current audience will likely want more content like that maintain the great content.

  11. Thanks everyone for the kind words, I apologize this hasn’t been updated in a while I have been deployed to Iraq and am now stateside again. As soon as I can I’ll start writing again.

  12. Tremendously helpful bless you, I believe your trusty visitors may very well want significantly more articles along these lines keep up the good content.

  13. Thanks for your helpfull information! I’ve got since last week a 305csr and i am going to repair it a bit like the way you did! It didn’t work for the last couple of years so i will see what i can do..

    The link of you didn’t work on my computer, the comp says that the file has been broken. But i’ve found another one, so maybe it can help other people who can’t open your file..

    I’ve found it on this forum and you can find it in the comment of mo8ius (01-27-2011)

    Greetings from Holland 😉

    • Greetings Hank! Now that I’m back in the states It’s time to continue to write and update. If you run into any troubles with your restoration feel free to drop a comment in here and I’ll see what I can come up with, also the good fellows at kawasaki twin owners forum are a wealth of information. I have been having some issues with word press hosting the large file for the manual so I’m off to work on a solution for this.

  14. It’s in reality a nice and helpful piece of information. I’m satisfied that you just shared this useful info with us. Please keep us up to date like this. Thank you for sharing.

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