Topic: My '79 CB650

[Soos]

I initially bought my '79cb650 as a rolling chassis.

A co-worker had a frame for a 650 he had, it used to be a complete bike he sayd, until he got it recovered by the police.
It had been stolen and stripped of all but the wiring harness, carbs, wheels, frame and seat. Motor supposed to have had about 25,000 or 30,000 miles on it.

It was a sad condition bike, but it had a title, and i knew of another'79 that was a parts bike for cheap.
From then, i got it running for about 50 or 60 bucks, with scrounging almost everything off the spare bike.
Looked ok, ran ok.




Since then I have changed quite and made a few parts...
-powdercoated the frame
-replaced the swingarm with a longer one off a '80's frame(1-2 inches longer, can't remember)
-changed gearing
-dual disk setup off a '79 DOHC750(forks and fender, disks, calipers)
-Master cylinder and splitter off KZ1000
-'85cb650 oil cooler with custom made adapter with for a spin on oil filter
-"superflow" 4-1 exhaust
-'73cb750k carbs - 28mm(stock 750)
-recently added '82cb650c bottom end w/cb750F pistons and ported head.
-exhaust collar clamps off a 750(sohc?Dohc? not sure) modified to fit the head/exhaust
-dyna 3.0 ohm coils
-Dr8eix iridium plugs
-dyna wires(copper core)
-'84cb650 voltage regulator
-'79DOHC spark units(mps200)

not much original left anymore, but uit keeps running better and better over time.


heres a pic or two of the head job, sorry for the poor pictures, i'm no photographer.

I'll add a pic of before the new motor, and now today.

l8r

[Soos]

Soon to go on this bike as well is a dyna2000 unit.
I inquired several times with dynatek's tech service.
I found out many very good bits of info.
ALL dyna 2000's for the inline 4 cylinder bikes are the same.
same advances/retards etc.
They all use different triggers and backing plates.

Having owned a '79DOHC750, and having a few tidbits left over, i decided that the DOHC kit SHOULD(hahaha... ?) work with a mod or two.
Being a machinist and curious(with a bonus check to burn) I ordered one.
The DOHC backing plate is smaller than a cb650's. And as for the trigger, i can't remember if i need to make a bushing or drill out the hole more.
Either way it's do-able.

Soon the newest toy will arrive...

Recently found a source for aftermarket springs for a 650 head to use a hot 550 cam.
I'll have to save up for that... but it's good to know there are possibilities!!!

l8r

[Soos]

Here are pics of the bike, and a closeup of the motor and the exhaust collar clamps off the 750.

[Soos]

I'm going to the garage today to re-check everything that can be adjusted by me...
I also got my package with the dyna2000 for a '79-'83 DOHC 750/900/1100
I was wrong about the crank sensor.... it's a drop on part..... gonna have to measure the backing plates for dimensions for the adaptor ring though.
And then wait to install it until I can figure out what is up with the tapping in my head....

Ahhhh... i'm feeling much better now!
  Gotta luv new parts 


l8r

[Soos]

hahaha....

I re-adjusted the valve clearances...
The tapping in my head is gone.
I found 0.003-0.005 thou too much clearance on all of the valves.
I figured i would probably have to re-adjust, just not this early. Go figure.
I'll do it again at 100 miles to see if it has changed again.


The Dyna2000 is going to be a chore getting it going. But it should work.
The backing plate is either going out the window, and i'll make a new backing plate, or i may try to graft it to a cb650 backing plate.
I could modify a spare backing plate to accept the dyna triggers I guess.

Not too sure yet.

The crank sensor is going to need the roll pin removed, and a longer pin installed for the extra reach needed.(I think Paulages had this problem too)
The crank sensor will also need a custom washer, but the bore of the dyna crank sensor is a tight fit ocer the stud sticking out of the 650 crank, so no hole size change needed.
The 650 crank has a stud, and the DOHC750 uses a bolt to mount on the crank sensor.

After thinking about it for a bit.... I'm going to drill the appropriate bolt pattern on a spare  stock cb650 plate to accept the new dyna triggers.
It looks to be the easiest of the options. Not as good as making a custom one. But it will do for now.

l8r

[Soos]

Well, after taking a 2 hour lunch at work, I have modified a stock 650 timing plate to accept the dyna2000 triggers, and modified the crank sensor to accept the correct pin.

The timing plate was the easy part...

The crank sensor pin was on the wrong bolt circle so I had to make a stepped pin, to allow the pin to locate on the correct bolt circle.

I love being a machinist....

I will post the results after i get things running.....
Can't wait for all this to work!!!


l8r

Oh, heres some pics of my handywork.

[Soos]

Well, after my battery charges, i will find out if all this money/work was worth it....

Kinda nervous.

Heres a pic of the temporary set for the dyna2000.



l8r

[Soos]

HOT DAMN!!!!!!!!!!!!!!
It works!
That startup was better than the initial startup with the new pistons!!!


Now just to decide whether the 2.2 ohm coils should go on as well.
Off to go tidy up the wiring, and come up with a home for the dyna2000 unit.


l8r

[Soos]

Well....
I had 200 miles-o-smiles!!

then just kinda died.

wouldn't start again.

thought something was REALLY wrong....


And come to find out the cam chain split.
One of the previous owners had attempted to link the camchain together with an ALUMINUM RIVET.
ARGH!!!!!!!!!!!!!!!!!!!!!!
ALL that work to the head, the porting, the polishing of the valves...

ARGH!!!
Gone....

The 61mm pistons and the bored out cylinders are on a older 40,000+ mile motor with no headwork...
I gotta say, I MISS MY HEAD!!!!!!!!!!!!!!!!!!!!!!!

The power is definitely less with just larger pistons, compared to the pistons with a home-done head job.

I went into a frenzy of teardown, inspection, cleaning my older motor, teardown of that one, cleanup, install 61mm pistons and the dyna again.

With the OT i've been doing, a family life and the bike work, it's been a busy week!!!


Oh well......


The pistons slapped against one exhaust valve REALLY bad and bent the hell out of it.
Another exhaust was tapped enough to bend as well as 1 intake valve was bent.

I guess this gives me reason to do a CV head-job now....


i'll post pics if i can find where i flung the %^#%$#@ cam chain.
The head is at least salvagable...
Will need new guides and valves though.

Figures... the 10k motor blows up, and the 40+k motor is doing well.
hahah....



l8r
l8r

[Soos]

Well.....

I thought I would add the new GPZ600 Kawasaki carbs...
 
Went on easily(without airbox on mind you), the only problem I encountered was the cable length.


The throttle cable had to be shortened(used a old but usable one)..I cut 2 inches off(now i wish I had marked my cables, don't know off a '79/'80 650 or a '81/'82
cb650  )


For the (?)ferrule on the end I took some 1/4 inch  stainless steel tubing, turned the OD to .225, drilled a 0.078(2mm) hole 0.200 from one end of the tube, then cut the end with the hole into a piece 0.400 long.

I threaded the cable through the small hole, and hammered a section of allen key into it (lined up the cable hole with one of the flats on the allen wrench),cut to length with a hacksaw, and ground it to the length of the
ferrule I had made.
I also brazed the whole thing together.(for safety)
Looks kinda odd, but it works.
I should have cut another 1/4 off the cable though.... i'm at the limit of adjustment for the cable almost.



Anyways....WHOAAAAA!!!!!!!!!!!!!!1
Went for a "ride around the block"... or thats what I told the wife.   
Just got back from a short ride in provo canyon, and a bit of highway/in town riding as well.

I tried MAX acceleration on this short loop, onto and off of I-15, by my house.
With the 650 carbs it hit 55-60 consistently.
With the 750 carbs it would easily get to 70mph.(75 almost 80 if i timed it right for shifting)
Now with the GPZ carbs, i hit a bit over 80, not quite 85.



In comparison to the stockers, i'd take these ANY DAY.
The cb750 carbs I was using, The oldschool look has it's merit. (love that choke linkage!)
The GPZ carbs look like any other CV carb set(of the 80's) pretty much.
Throttle response is better on the GPZ carbs than the 750's.


GPZ jet needles have 6 grooves for the circlip. They can even be changed ON the bike!!
Main jet is 108, didn't check the idle jet size.
The GPZ's  main and idle jets are screw in type. 

I simply gave the passages a good cleaning, cleaned the jets main and idle...  everything inside was good except the float needles.
I robbed another set of carbs laying around for new(er) one.

Hoping to not have to re-jet. They 60mm bore motor and my bike is 61mm bore.
I'm guessing for my altitude i'm probably OK.
Wonder if they will get worse or better MPG than the 750 carbs.

l8r, gotta ride.

[cb650]

Do the kawi carbs have a choke cable or  a lever?

[Soos]

It needs a cable, but I can engage it by hand for now.

Looked up more about the kawa GPZ600, I gues it was called a ninja.


l8r

[Pinhead]

Very nice project. It's good to see a couple hardcore 650 members (Soos and Paulages) here at SOHC4. I'll be one of you guys this winter; I'm going to be doing similar work to my '79, though I'm aiming for max thermal efficiency. Good to know there are some knowledgeable 650 mech's around!

[Soos]

WOW..... I was showing a co-worker the carbs, and he wanted to rev it...

I told him of the rev limiter, so he went WOT, and the exhaust shoots flames out the back when the rev limiter is hitting!!!

I'm really gonna have to do a video... If i would just rember to hook up my camera docking port at home.

Thnx pinhead. I'm no guru(although i like to think so at times) I just like to see how far things can be pushed.
You never know your limitations until you go too far.


l8r

[Hush]

Ha you've got the same model 650 as me Soos, does yours sound like a tin can full of stones shaken right next to your ear?

[DarkRider]

Have you even done another ported head yet man? Because if the bike is performing like that with just the larger pistons and Ninja carbs..imagine what its gonna be like with a ported head and a new cam (well new cam if the one that was in the engine wasnt destroyed when the chain went)

[Soos]

Ha you've got the same model 650 as me Soos, does yours sound like a tin can full of stones shaken right next to your ear?

It does have a noticeable(to me) rattle under 2500 rpm coming from the left side of the head.
I'm guessing just excessive clearance... but it goes away(oil pressure related?) as soon as I hit 3k rpm.

MY wife can't spot the ticking i'm hearing, but i know the motor sound well now, so i spot it easily.


l8r

[Soos]

Have you even done another ported head yet man? Because if the bike is performing like that with just the larger pistons and Ninja carbs..imagine what its gonna be like with a ported head and a new cam (well new cam if the one that was in the engine wasnt destroyed when the chain went)

Yes... and it's sitting waiting for this winter..... After 2 new guides and a new(used) set of valves,keepers,retainers.springs....

I have just recently finished work on the same head that had the cam chain failure.
Before i put this one back on, theres other work while i'm in the motor I need to do.

If I had another bike to ride right now, i would drop it on.
It's almost torture seeing that head sit in the garage....

l8r

[Soos]

Update on carb fitment..


The kawa ninja airbox to carb boots were a bit small for the airbox holes.
I tried stocker '79 boots there, wouldn't fit over the carb opening.
However a set off a '82cb650c TIGHTLY fit in the airbox and mounted to the carbs a bit loose, but nothing bad.
The bands took care of that quickly.

The air filter I have been running is gutted down to the wire mesh and mounting ring only.
Almost like pods, but the carbs behave better.(the pod filters I have do not quite fit these carbs...so this is the next best thing for now)

Have found a throttle cable that works, but barely.
I borrowed one off a buddy's '81 cb650c and it fits with everything at the max adjustment.


I really cannot say anything bads about this drop in..
Well one, I wish I was running a CV head, as these carbs are nearly a perfect lineup.
But using the Kawasaki carb isolators they allow these carbs to fit on a '79/'80 650 head..
 

l8r

P.S. anyone know of what the old ninjas used as hop up carbs?
 

[Soos]

heres a few pictures from right after my first ride.

l8r

[Hush]

What sort of top speed can I expect from my stock standard 650 Soos?
I know what the book says but it also has wiring diagram errors so I aint trusting much of what they say.

[Soos]

With all that baggage you got?
Dunno.
Or do you have a non cop bike as well?

on the best run I ever did with the stocker carbs and stock pistons, the speedo read 125 130'ish?
Mind you thats by a 29 year old speedo.
I'd guess it was more like 115 mabey 120.

but it took a LONG stretch of straight road, me tucked on the tank. Oh did i mention i'm 150 lbs or so.
160 soaking wet. Oh... metric weights say about 70 kilos or so.

That was in fine tune all around, timing spot on, valve clearances set recently, new spark plugs, recent oil change etc.
The only real change at the time from stock was the rear tire gear. I run a 39 tooth rear drive gear.



And top now?? I have no idea.


I've found out some of what it takes to run at the Bonneville Salt Flats.
The run what you brung class they offer at times sounds to suit my bike.
More of a track race than a timed 1/4 mile or top speed run event though.

Would love to be able to do a max speed run, but the fees(and safety gear) for that are steep.
Who knows mabey one day.



l8r

[Hush]

Happily there is a Run What You Brung here in my part of NZ this weekend, $20 for a day licence and $10 to enter a bike on a nice staright back road.
Shame my bike aint fit to ride yet or I'd do it lights siren and all blaring the whole 400 metres ha ha ha.

[troppo]

Happily there is a Run What You Brung here in my part of NZ this weekend, $20 for a day licence and $10 to enter a bike on a nice staright back road.
Shame my bike aint fit to ride yet or I'd do it lights siren and all blaring the whole 400 metres ha ha ha.

And dont forget hush, when you do we want the FULL video 

[Hush]

Yeah still figuring out how to strap Jaffas video camera onto my bike, I should be able to do it as I'm a trained Vid-cam operator at work.