Author Topic: 1978 KZ650 Cafe Racer "Jellybean"  (Read 31418 times)

Offline CafeRacer650

  • Posts: 353
  • Dream it. Build it. Live it.
1978 KZ650 Cafe Racer "Jellybean"
« on: Sep 12, 2012, 23:20:59 »
Alright all, after 130+ posts without a build thread, I'm overdue.  So here it is...

The bike: 1978 KZ650C (code named "Jellybean" - thanks to my wife)

Taken shortly after I restored it in '07.

History: 1999-present

I was a Senior in high school and my best friend of many years went out and bought a beautiful 1977 KZ750 twin.  I fell in love instantly and had to have one of my own.  Later that summer I drove to Ohio and picked up another beautiful KZ, Jellybean.  It had been owned by a younger guy who had installed a 4 - 1 exhaust and tore the baffle out.  My parents hated me and so did my ears. 

After riding it for a few months, I dropped it after misjudging a sharp turn and cracked the fairing, bent the bars, among other thing.  All that meant was, NEW PARTS! Yay!  After riding it for several years, wooing my girlfriend (now wife), I decided to do the right thing (according to her father) and sell my baby to by an engagement ring.  But I convinced everyone that the best course of action would be to restore it, and THEN sell it for better profit. 

I began the restoration... we got engaged... not finish... we got married... still not finished... FINALLY I finished it but by that time we had already payed off the ring (bummer- hehe).  SO I had to keep it.  It ran well for a while until one trip where it spent a little too much duration while hitting the ton.  A float stuck open, and ever since, never ran right.

I poured over the bike when I could trying to diagnose the problem.  I even resorted to taking the bike to a dealer, who in turn, made it smoke, didn't fix it in the slightest, and charged me a grand.  Not a wise move.

So, long story short (too late) and after many life changing events, I am finally in a place where I can REALLY fix my KZ.  Since it has been in storage, I've happened upon cafe racers and knew Jellybean had a whole new future, and it begins now.

Past Images: 

This is what she looked like when I bought her in 1999.

A looker if you ask me!

The Restoration:

My parents loved their garage looking like this for two years.

New rings

Almost done...



Started to tear it down, and threw on a cardboard mock-up of the seat size I'm thinking about...

Sketching out some ideas...

Tear down continues... oh great, oil in the combustion chamber.  Peachy.

Carbs off.  Starting to see more issues.

I've only torn down two carbs and one cylinder is seized.  Awesome.  The gas that had sat in the carbs has turned to a sticky sludge.

If I'm going to get this thing going, it means... NEW PARTS YAY!

This is how she sits right now, waiting for me to not be so dang busy!

I apologize for the phone camera shots.  I swam with my Nikon earlier in the year.  I hope to correct that in short order.  I will also get into more detail as I go, so it will be more useful for everyone.  Thanks for looking!
« Last Edit: Jan 14, 2013, 14:43:37 by CafeRacer650 »
Motorcycles are my personal art medium!
"Jellybean" Cafe Build -


  • Guest
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #1 on: Sep 13, 2012, 13:59:32 »
Great intro.
Looking forward to see where you go with this.

Offline rocketman

  • Posts: 235
    • My build thread
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #2 on: Sep 13, 2012, 18:00:15 »
Great to see another proud kz650 owner here.  That bike looks like a really clean bike!!!

Offline CafeRacer650

  • Posts: 353
  • Dream it. Build it. Live it.
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #3 on: Sep 14, 2012, 15:18:24 »
Thanks guys, and yes, I am a VERY Proud papa! 

I missed a couple things I've done already.  I took the front fork off and dismantled the gauges.  I harvested the wiring which is in good shape, and I've decided to fabricate my own little dash area using a mini tach and speedo from Dime City.  That will be a little while down the road. 

Current Goals:

Get it running.  It has sat for almost two years and it shows.  I haven't looked in the tank yet, and I'm sure that'll be just as ugly as the sludge in the carbs. 

Getting it running will require a Valve adjustment, new head gasket, new battery, and rebuilt carbs.  I have all the parts and tools and I'm ready to go.  Stay tuned. 
Motorcycles are my personal art medium!
"Jellybean" Cafe Build -

Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #4 on: Sep 15, 2012, 08:24:00 »
nice drawings... i like stencil design much more than photoshopping ;) the right one in the middle is my favorite
« Last Edit: Sep 15, 2012, 08:25:48 by MoToBoX-VintageSpeed »
>>>>>>> <<<<<<<<

GSXR 1100 87 Modell Daily Driver
GSX 1100 Katana (buildt up to a 1127 GSXR Katana)
KTM 600 LC4 becoming a 620 Flat Track soon
KTM 660 LC4 going to a CafeRacer
V 65 Lario Compressore buildt up to a LSR Bonneville V7 Style Café Racer
BMW K100 RS going to 36HP Challangebike

Offline CafeRacer650

  • Posts: 353
  • Dream it. Build it. Live it.
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #5 on: Sep 20, 2012, 13:13:29 »

I've got an idea of where I'm going with the design of the bike.  Here's a quick rendering of my plans...

Motorcycles are my personal art medium!
"Jellybean" Cafe Build -


  • Guest
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #6 on: Sep 20, 2012, 15:24:23 »
The color and graphic treatment is reminiscent of the first gen Moto Morini 3-1/2, one of my top 3 bikes of all time.

Offline CafeRacer650

  • Posts: 353
  • Dream it. Build it. Live it.
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #7 on: Oct 01, 2012, 10:21:01 »
Carburetor Rebuild:

I decided I would go ahead and do a serious rebuild and refinish of my carbs even though I haven't run the bike yet.  I figured since they were in good shape, i could sell them if the bike doesn't work, but I'm pretty sure it will.  Anyway, after much research on correct materials and some trial and error with polishing, here is my process for rebuilding a set of Mikuni VM24 SS carburetors. 

Materials and Parts:

Here's a list of materials I found to be the best tools for the job:

1) Paper Towels (and a lot of them)
2) Waterproof sandpaper (I used 400 and 600 grit) - Ace Hardware has a good selection of sandpaper
3) A couple cans of compressed air - Walmart and Walgreens carries this
4) Cheap hand clamp for pulling carbs out of cleaner
5) Dremel tool - 2 speed corded model from Lowes
6) Dremel Cleaning and Polishing kit - Walmart or Ace hardware
7) Safety glasses - Walmart
8) Narrow shaft screwdrivers - Lowes
9) Gunk Carb Cleaner - Advance Auto Parts (good stuff)

10) 4 rebuild kits - Motorcycle Superstore
11) 4 Pilot jets - 17.5 (based on research for a KZ650 with pods and a mild exhaust) -
12) 4 Main Jets - 115 (based on reseach for a KZ650 with pods and a mild exhaust) -

13) Mother Aluminum Polish (My favorite) - Walmart or Advance Auto

More Polishing goodness to come later.

Disassembly and Cleaning

Tear down the carburetor assembly and keep the parts organized.  This is a simple process, but having a manual helps a lot.  After separating the individual carbs, disassemble them one at a time and keep the parts together in a labeled container. 

Make sure all removable parts are removed from the carb body before cleaning.

Cleaning the carbs is simple, but annoying.  It's messy and the cleaner is highly toxic... when they say use a well ventilated work space, do it.  The Gunk cleaner does a quick and good job.  I tried Chem Dip, but it leaves and oily film on everything which isn't great for carbs that have very small holes that get clogged easily.  The Gunk cleaner cleans faster, and since it is an Solvent based cleaner, it dries faster and rinses easier.  On the can it suggests a 20 minute soak, but since my carbs were covered in rotten gas, it took up to an hour and a half to get them clean.  The only parts you need to soak in the cleaner are the main carburetor body, the float bowel, and the body caps.  If you aren't replacing the other parts such as needles, springs, and jets, you can soak them, but do not do it for long because they will begin to corrode.  I used gloves (mechanics gloves - rubber gloves fall apart shortly after contact with the chemicals) and the hand clamp to pull the carbs in and out of the cleaner.  Rinse them with water and blow out all the holes with canned air. 

More to come soon, and thanks for reading.
Motorcycles are my personal art medium!
"Jellybean" Cafe Build -

Offline CafeRacer650

  • Posts: 353
  • Dream it. Build it. Live it.
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #8 on: Oct 30, 2012, 01:36:30 »
The Carb Rebuild Continues...

After a little work, I decided to go out and add to the materials list, and here is what I've added so far:

1) 800 grit sand paper ( Advance Auto )
2) 1500 grit sand paper ( Ace Hardware )
3) 1 Gallon of Denatured Alcohol ( Lowes )
4) DupliColor self-etching high heat primer ( Advance Auto )
5) DupliColor Aluminum Colored high heat paint (Advance Auto )
6) Cheap Ladle ( Walmart )
7) Baking pan (Walmart )

After doing some sanding, I decided I needed to go even higher with the grits.  600 was close, but not close enough.  So far I've wet sanded with the 800, and it looks great.  The Denatured Alcohol is for cleaning off parts for paint.  For paint I decided to go with Duplicolor.  I will experiment with it and provide feedback shortly. 

Here's what I bought the cheap ladle and baking pan for:

Cleaning parts that won't fit in the parts cleaner can.  This method works great, but make sure to cover the pan while soaking the parts, otherwise you'll peal the paint off the shop walls.  :)


Here's a little step by step of what I've been doing so far in regards to polishing:

Dry sand with 400 grit paper.

Wet or dry sand with 600 grit paper.

Wet sand with 800 grit paper.

Polish with Mothers Aluminum Polish using a buffing attachment.

The final product.  I prefer to keep the larger blemishes in the metal because they make up the character of the motorcycle.  However, I might try the 1500 grit paper and see what results I can get. 

This shows the carb caps in different stages of the polishing process.

SIDE NOTE:  Another fantastic tool I recommend ( if you are using a dremel tool ) is the brass brush bit.  It is softer than the regular wire brushes so you can really work it into the metal and it doesn't scratch our gouge the metal.  Its great for getting stubborn grease off of metal parts.

As it stands, parts are soaking, and will soon be painted.  Next is paint and polishing the carb bowls.  Stay tuned! :)
« Last Edit: Oct 31, 2012, 10:36:12 by CafeRacer650 »
Motorcycles are my personal art medium!
"Jellybean" Cafe Build -

Offline canyoncarver

  • *
  • Posts: 3946
  • 'hacking is learning'
Re: 1978 KZ650 Cafe Racer "Jellybean"
« Reply #9 on: Oct 30, 2012, 17:38:41 »
Killer build thread so far.  Love the drawings, nice work.  Glad you posted the carb build stuff.  I've got a 78' KZ650 waiting on some love and your info is helpful.  Love the red.