Newbie here with some Q's

[SkiLLzCb650c]

I just picked up my first bike....81 Cb650c with 8,200 miles for $150 with two other motors and a frame and both titles. I got a deal wooohooo!!!

Anyway the guy I got it from works on Hondas and had at least 5 in his garage...mostly cb750's. He told me he messed with it...it was his sons....and he couldnt get it to fire up but said it would try.

I have since getting it
-replaced plugs.....18mm craftsman deep I LOVE YOU....took forever to figure out the right socket....was using a matco 18mm too long
-put a cap full or two of oil in the cylinders before starting
-new battery
-rewired the run/stop switch to a 81 cm400c switch
-cleaned carbs......carbs 1+2 appear to be leaking from either the bowl gaskets or somewhere else near the center of the two
-Cleaned tank with THE WORKS toilet bowl cleaner
-Fresh gas
-Shined her up
-Swapped the frozen choke cable with one from the cm400c...too long but works for now
-Swapped a few goodies from the cm400c.....grips, mint peg rubbers, headlight + housing

Anyway I have NO SPARK. I doubt its the coils......fuses are good.....both coils prob wouldnt die together
Wiring from under the seat at the aluminum box things to the coils and resistor? cover looks ok
I dont know much about bikes at all but am learning quick through this site and a few others.

Im about to go pull off the cover and see whats under there......I had it off before but it looked ok
Any info would be greatly appreciated....I have the owners manual and the honda manual online for the bike



got this thing for $50 no title 3232 miles

[SkiLLzCb650c]

I also swapped the ignition switch off of the cm400 and the starter button works only when the switch is in the P position. This switch has off, a red dot, then P. Maybe this is my prob? The dummy lights only light up with the key in the P position too.

[Ibsen]

I would not be surprised if the CM ignition switch doesn't match the 650 electrics.
What's wrong with the 650 ignition switch btw?

And here is the wiring diagram for the US 650.

http://kz400.com/CB650/Rotation%20of%20 ... wiring.jpg

[SkiLLzCb650c]

The ignition switch is different......i dont have the key for mine or the wiring that hooks to it. I have a red 6 wire harness where it should hook to. I checked the honda manual online and I straight wired the harness instead of using an ignition switch. With the harness flipped upside down (clip on the bottom) I crossed the bottom two wires (batt + ignition) starting on the left to each other......and the top two wires (tl1 + tl2) to each other. My gauges are on but still no spark.

[SkiLLzCb650c]

I HAVE SPARK!!!

I swapped a few of the black wires coming out of the kill switch harness....cm400 switch wired to cb650 switch........and voila!!! spark!!!
Wanted to start but battery was about dead from testing for spark it wouldnt do much. Charging it right now.

I still have gas leaking either out of the carb bowls or around the middle of 1+2.
I also noticed a nice mist of gas shooting out of cylinder #4 exhaust.......pipe to engine baffle?
Wheels need replacing......have some on a 79 yamaha 1100 that are in great shape....hopefully fit same diameters though
Brakes prob need done......master cylinder overhaul
etc etc etc

[SkiLLzCb650c]

pulled the bowls on 1 + 2 and the floats stop the gas from coming out when pushed up.....check.....what now......
my air box was full of gas.......cylinders too most likely......so pull the plugs, get the gas out of em.....then what
she wants to start sooooooo bad!

also these are plastic floats

[SkiLLzCb650c]

Ok.....now i have gotten the carbs to stop leaking somewhat.....I put the bike on the center stand and they dont leak but when on the kickstand they do. Where is the overflow for the bowls??? They dont have a tube that come up......

Anyway she wants to startup but i have a huge exhaust leak. All 4 cylinders are spitting smoke out right at the head. This isnt the stock pipes seeing as this is a custom and the pipes are 4-1..........Is this ok? Any advantages/disadvantages?

How do i fix the exhaust leak? Exhaust wrap?

[cb650]

Thats a MAC exhaust. Its lighter than your original 4-4. I have 2 of them on a couple of mine. There is a copper crush gasket between the headpip and the head. Might just need to replace them. The 79 yami wheels wasnt that shaft drive? Would be problem at the rear.




Terry

[SkiLLzCb650c]

I took the exhaust off and the guy I got it from had only put one of the copper gaskets on..........thats my prob. Tried to get them off the yamaha but not working......just tearing them up.

The yamaha is shaft driven........I just want the tires no wheels.

So now I have to order some exhaust gaskets and prob wait a week on em.........anything I can pick up at the hardware store that will work?

[Ibsen]

There are many models that use the same size gaskets. If you have a Honda dealership nearby you can take the gasket you have got to them for comparison and they should have replacements that fits.

[SkiLLzCb650c]

Thanks Ibsen.....right now I have some on off of a 79 yamaha 1100. They were too big but I cut em and stuck them in. Good enough until monday. Still small leak on two but not as bad.....no gas spraying out but does smoke a little.....check out my other post and see if you can help me there.....thanks

[Volker_P]

Welcome here

That's really a nice-price buy!

The CB650 is a simple and user friendly bike and so quite suitable for a beginner in work on bikes. However the old-fashioned chassis is not really what a beginner needs so do not try to follow other guys with modern bikes as your reserves are much lower.

Seems you already solved some of your problems. I am sorry I can't help with the CV carbs. But after a standing time this is often a problem of dirt at the floater needle valves. Did you check for rust in the tank? Or maybe floaters just stick, then slight (!) knocking with a piece of wood on the floater bowl may stop leakage. This kind of problem may even vanish without further measures after a time of riding.

To used tires: besides wear, also the age is important. With "brand new" ten year old tires you probably will fly off at the first slightly wet corner or when touching the front brake a bit harder. This depends also on storage conditions, hot and bright is bad.

BTW: if you have a bit of oil to dump somewhere, your chain would be the right place

Have fun with your CB!

[Chris]

Welcome, SkiLLzCb650c.