78' KZ650 Bobber

So the story begins when I sold my 06' zx6r. obviously it didnt take long for me to realize how stupid it was and that i missed being on a bike. So i decided to to build a bike that truly would be mine.
I scored a 78' kz650 for $200 which included title transfer. The motor was locked up but supposedly it drove when it was parked 3 years ago and it has obviously seen better days.
Im going to do a hard tail conversion on the frame and a different gas tank. also eliminating the electric start and some other misc stuff.

So i started the tare down process





After i got the carbs off i noticed that they were really clean and everything moved very freely. so decided to drain the oil and pull the inspection cover. Found the oil was clean and the motor was not stained. So i decided to try a trick i have used before on cars to free up motors. I pulled the plugs and filled the cylinders with diesel and let it sit for about two weeks. syphoned the diesel out and worked the kick start pedal slowly and like magic i now have free spinning motor and found good compression.
So i went to town on the harness. which was a good thing cause i found some damaged wires and bad repairs. plus since im getting rid of some stuff i pulled unneeded wires out of the harness.
I decided to do away with the horn, electric start, on/off switch for the lights (gonna wire the lows on at all times, horn, and clutch switch. meaning i can shave them off the switches for a better look.





after the first round of welding, filing, and sanding. still need to do another round. forgot how much i dont like welding cast aluminum.




waiting on a couple misc parts so i can continue my journey.

finished shaving and cleaning up the right side control and clutch control. decided to order a left side control from a different year cause it only has the things i want. went through the entire harness and got rid of stuff not going to be used and fixed some crappy repairs done by a previous owner.

also made a new pedal for my kick start lever


order a new clutch cable, battery box, and some other misc stuff. once i get that stuff in i will probably order the material to make my hard tail. Ill try to get some more updated pics and get some more part made soon.

Do you guys think I should just do a trapped swing arm or should i completely ditch the swing arm for the hardtail?

welcome.
ditch the swingarm and the back of the engine cradle and do a single seat post.
i like all the fab work.
keep us posted on your progress.

leon

i think that this guy did a real good job on this one.



here is a link to his thread on chop cult.

www.chopcult.com/forum/showthread.php?t=8358

leon

although the tc bros. kit don't look to bad on this one.



leon

minor update.
Did some more little minor things.
unfortunately it looks like im going to have to rebuild my carbs. Since I got the bike to where it would fire over with starter spray i wanted to see if it would run so I brought home my tool for doing induction flushes on car (basically just a canister that gravity feeds fluid and has an on/off valve) when i opened the valve gas started running out of the ports (part where you would put pod filters) anyone know something i dont know. i noticed that this bike has a vacuum petcock does that have anything to do with it? If someone can help before i unneedingly spend $125 to rebuild the carbs it would be greatly appreciated.

On an upper note i have gotten some more goodies in

tank im probably gonna run didnt like the hard edges of mine i only paid $10 for this on on ebay


stripped the cluster down and made a template for a plate that will house the new indicator lights






cleaned up the inside and out side of the headlight lens and put in an 80W/100W H4 bulb i had in my tool box and scuffed off the rust and gave it a coat of self etching primer




new fuel line, fuel filter, and battery cables


got some red LED rear turn signal/running lamps. also ordered some yellow ones for the front


also scored a used passenger pad for the misses that just so happens to match the seat im gonna get for me and with a little cleaning will be just as nice

BizzareCustoms wrote:

...looks like im going to have to rebuild my carbs......when i opened the valve gas started running out of the ports (part where you would put pod filters) anyone know something i dont know. i noticed that this bike has a vacuum petcock does that have anything to do with it? If someone can help before i unneedingly spend $125 to rebuild the carbs it would be greatly appreciated....

First guess would be excess fuel getting past float valves (for whatever reason) and overflow circuits clogged, whereby gasoline rises up into the carb throat, and flows both ways, back out the air-filter side and forward on through the intake ports into the combustion chamber and down past the pistons into the crankcase.

Would sniff-test crankcase oil and examine it to determine whether there's been any fuel intrusion into the crankcase (which can result in catastrophic engine failure).

A malfunctioning vacuum petcock can exacerbate the problem by failing to stop fuel flow from the tank to the carbs while the engine isn't running (same as if leaving the petcock set on "prime" which flows fuel constantly without regard to vacuum).

Good Fortune!

yea i have gas in the oil noticed it today before i read this. so sounds like im going to be rebuilding some carbs. Best off might as well at least this way i know everything is good and I wount be randomly stranded or kicking the motor over for an hour trying to get it to run. Is there anywhere that will sell a whole 4 carb kit cheaper then $120 (buying four individual kits). i havent been able to find any. I saw a pretty good write up on rebuilding them and jet selection so i can rejet it while i have it apart also.

BizzareCustoms wrote:

yea i have gas in the oil noticed it today before i read this. so sounds like im going to be rebuilding some carbs. Best off might as well at least this way i know everything is good and I wount be randomly stranded or kicking the motor over for an hour trying to get it to run. Is there anywhere that will sell a whole 4 carb kit cheaper then $120 (buying four individual kits). i havent been able to find any. I saw a pretty good write up on rebuilding them and jet selection so i can rejet it while i have it apart also.

Why re-jet, as existing jets might be okay, and won't know until engine is running.

Might not need any other new parts either.

Would thoroughly clean the float needles and seats (keeping them paired together), which might resolve the overflowing.

And also thoroughly clean the overflow circuits from inside the float bowls through drain hoses exiting underneath the bike. So the overflows will work next time they're needed.

Assure the floats aren't leaking or sticking or installed upside down.

Bench sync the carbs.

Before further addressing carb tuning, would suggest first assuring acceptable compression, proper valve clearances, fat blue spark, correct ignition timing, and advancer function.
Because even perfect carbs can't compensate for deficiencies in the other components.
For instance, with poor spark or leaking valves, etc., it's a waste of effort to address carb tuning.

When cleaning the carbs, use lots of compressed air and carb spray, and always wear eye protection.

Good Fortune!

well scratch the price question i just started looking through some other threads and found a link to z1enterprizes and see that i can probable buy the top and bottom gaskets for about $25 for all 4 and just clean up all my parts unless i find something that needs to be replace. Ive only ever done car carbs so these are a little different to me.

sorry i replied before i saw your responce. yea thats the route im going to go. im going to take them into work with me and do it in between jobs.

So just to check, after the overhaul, for testing purpose i should be able to use my induction can (with no vacuum petcock) to get the bike running and adjust and sync the idle on the carbs?

also if someone could post some close up pics of their carbs on the bike for vacuum, fuel line, and caps reference, that would be awesome