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1983 CB650SC Nighthawk rescue

what sucks is my cm400a has overflow tubes in the float bowls so i would be able to tell which carb it is, these only have drain screws with no overflow tubes.
 
wow, gusher of gas/oil came out. must have emptied the tank. all clean and new filter now. attacking clutch next
 
wow, gusher of gas/oil came out. must have emptied the tank. all clean and new filter now. attacking clutch next
I'd check the oil for fuel contamination, the breather tube goes into the airbox on the later bikes and if the engine oil has fuel in it from flooding carbs previously it could have blown some out into the airbox. This engine has plain bearings, you definitely do not want to run it with diluted oil.
 
I cannot get that bolt out no matter what tricks I try. I'll let some pb blaster soak in overnight. Its no longer hex, just totally stripped. I already have a spare. Might have to keep reverse drilling it.
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i think i may dremel a slot in whats left of the head and try a screwdriver
Make it a thick-bladed one with a stout handle, then use a crescent wrench on the hex or square shaft if it has one to give you more turning leverage.
 
That allen bolt.. I have had success by using an allen socket w/ 3/8" drive.
I have a set of metric allen sockets(is that a 5mm or 6mm allen?)and also a set of 3/8" drive SAE allen sockets. Take a drift punch and medium hammer,place the punch inside the center of the rounded-out allen head bolt and give it a few sharp 'Hits'/raps to break the corrosion free.
I have stripped the heads of a few 6mm allen bolts on the bottom of a fork tube during the process of disassembly:I will then take an SAE allen socket(the next size up from 6mm,but in SAE)and hammer it into the stripped-out 6mm allen head bolt hole and when I was done,I'm able to gain full 6-sided contact on the fresh surfaces. Basically 'cutting' a new size.
I like Lisle brand SAE allen sockets as they're strong and sharp on the edges too.
 
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I agree, sometimes these bolt/screw heads corrode to the cover and cannot be turned out by the screw/bolt head. Drilling slowly through the bolt/screw head and stopping to check your progress often is the easy trick to removal. Once the head is drilled through it will remain on your drill bit, be careful it will be hot. At this point you can remove the engine cover by breaking the gasket tension by knocking the cover with a rubber mallet or 2x4 carefully, and you can pull the cover off over the screw you drilled as if it were a stud you'd removed the nut from. After the cover is off remove the rest of the screw, start by trying to remove it by hand, but be careful it will be sharp so wear gloves, odds are it was the screw head that was corroded against the engine cover and now the threads will turn freely.
 
ok, i was able to drill away enough of the head to get the cover off, the bolt was loose after that. thanks.
Now, i'm no clutch expert so i need some understanding on what the bike should be doing and what is bad.
The inner hub spins freely in neutral and not when in gear, i assume thats good. The outer hub does not move, i can nudge it about 1/4" back and forth, thats it. I put the cover back on (its going to rain soon) and took the parts inside to measure clearances tomorrow. It was tough shifting up gears (FSM says to put in top gear and hold brake to remove lock nut which i opted not to do and I dont have a proper socket) but eventually with a little manual rear wheel move, it engaged all gears.
photo dump.

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The clutch center hub is on the transmission mainshaft so when in neutral it should spin freely. The outer clutch basket is part of the primary drive from the crankshaft so it should sit still. I'm sure you realize that bike transmissions don't shift well unless at least one shaft is moving, so you'll want to rotate the inner clutch hub (or rotate the rear wheel as you mentioned) while trying to shift the transmission and whatever you do, do not force it or pound on the shift lever to get it to shift, that's an easy way to bend a shift fork. Whatever you do to hold the inner hub still to loosen the nut, do NOT use the clutch spring posts to try to hold it still as it is fairly easy to break one off.
 
Do i need to remove the locknut at all. th FSM doesnt go much beyond that so other than inspecting the sides of the outer ring for wear, i don't see a point??
 
the new clutch springs i got are about 2 mm shorter than the ones in the pic. Would that make a difference it it not disengaging?
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lft is old spring (looks new though) and the right black is are the new ones.
 
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spring service limit is 34mm. old springs are 35.4 to 36.2mm, new ones run from 34.4 to 35.2mm
 
friction plates: old ones read 3.4mm to 3.65mm, new ones read 3.24 to 3.26mm. service limit is 2.6mm
 
Shorter springs will not affect disengagement, it's the distance of travel of the clutch rod that effectively disengages the plates It's odd that the springs you took out of it are longer than the ones you bought. Did you get the new springs from Parts N More? Are they supposed to be OEM? Just based on the old springs being shiny makes me believe they're aftermarket. And if all you plan to do is replace the friction plates and springs then no, you do not need to loosen the nut on the mainshaft.
 
also verified the petcock vacuum is not working, leaks gas in reserve position.
 
THE CLUTCH WORKS!!!!!!!!!!!!!!!!!!!!!

(with spare m/c and temp hose, next up, try the original m/c and oem hose.)
Yea, nice to get a win once in a while. And I learned what a vacuum operated petcock is - automatic, well when it works. Might consider bench testing with gas those carb float shutoff thingies, if you have to work on them again. I've never done this, but watched a you tube from a MotorcycleMD guy that showed it can be done. I'd guess 4 carbs are not much fun to take on and off or work on. Makes me happy I got only twins, with cable operated clutch ;)
 
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so now i have my carbs out again. I'll take it out back, fill it with gas by funnel until one or more of them leaks out the front, then fix those.
My driving lights and horns are now installed. LOUD horns!
For the life of me, I cannot figure out how to wire my hazard relay so the turn signals work and the hazard works. I did it on my 400 so I know it can be done but every combination i tried either triggered hazards from the turn signal or some combination of a side or indicator not working.
 
carb test out of the bike, no leaks. all 4 bowls full of carb cleaner and no leaks. should i tear it apart again?? Im waiting on replacement throttle cables so I have some time. I'm going to rewire the lights and hazards with proper switches instead of the on/ff one i was using.
 
not yet, probably wont have that until end of next week. Would the pressure of the fuel in the tank going into the carbs matter? Also would it matter that is was carb cleaner and not gas?
 
not yet, probably wont have that until end of next week. Would the pressure of the fuel in the tank going into the carbs matter? Also would it matter that is was carb cleaner and not gas?
I would be concerned the bad petcock/fuel valve are flooding the carbs and allowing gasoline to overflow into the engine and crankcase oil.
 
obviously, but maybe in taking the carbs out, i nudged the needle back in place. Even with a bad petcock, the needles should stop the flow.
 
obviously, but maybe in taking the carbs out, i nudged the needle back in place. Even with a bad petcock, the needles should stop the flow.
Yes they should, but they could also still seep a bit. Good condition, clean and functionally sound 14H carbs on a 450 will still seep sometimes if the petcock is left on
 
spent today swapping the master cyl for the original and original line, and of course, having a bitchh of a time bleeding it. At least i know the back end works. Wont be able to test t unti li get the engine back together though so i'll let it sit a bit.
 
I think im going to get a syringe and push the fluid from slave to master. Would that be better with the lever in the pulled position or released?
 
I think im going to get a syringe and push the fluid from slave to master. Would that be better with the lever in the pulled position or released?
That's a good idea. I think it will work well if you removed the bleeder screw out of one caliper at a time and quickly and carefully wrapped(only)the threads of the bleeder screws on the calipers with a little teflon tape,then pump fluid upstream from one(start w/ the further/left?)caliper at a time:air rises.
I imagine you will see some air bubbles disperse into the master cyl reservoir.
I think "released", imo.
 
these arent brakes, its the clutch so there is no caliper. just the slave cylinder. the bleed screw currenlty has teflon on it but I bet i've worn it down already.
 
decided to inspect all the float needles and valves.
#4 gasket was new, now expanded. float and needle are good.
#3 gasket ok, float is level is low, needle good
#2, gasket almost expanding, float is low, needle ok
#1 gasket ok, float ok, needle soso, replacing.

I'm ordering 4 new floats and 4 new gaskets. All 4 gaskets were new, now sure why they expand.
 
decided to inspect all the float needles and valves.
#4 gasket was new, now expanded. float and needle are good.
#3 gasket ok, float is level is low, needle good
#2, gasket almost expanding, float is low, needle ok
#1 gasket ok, float ok, needle soso, replacing.

I'm ordering 4 new floats and 4 new gaskets. All 4 gaskets were new, now sure why they expand.
How's your fuel valve/petcock working now:have you fixed the seal yet?
When the fuel valve doesn't shut off,the weight of the fuel in the tank puts lots of pressure on all the float needles(it overcomes the small springs)which causes the fuel to seep out and overflow into the cylinders,etc.
 
the carbs are out of the bike. im waiting for the new petcock still. wont have everything now for 2 weeks at least.
 
also getting a bleeder banjo bolt for the top end.
That's got a certain ring to it! I like it. I assume that is a banjo bolt with a bleeder, hopefully not a bleeding banjo bolt.
Any thoughts on bench testing the carb float gas shut off valves while they are off? I think I will try this next time around. I've just had too much
trouble with these things.
 
I've tested the needle valves against my breath and against a full fuel line of carb cleaner and they held fine. 3 of my 4 floats are too high so im waiting on the new ones. they are the palstic non-adjustable ones.
 
I've tested the needle valves against my breath and against a full fuel line of carb cleaner and they held fine. 3 of my 4 floats are too high so im waiting on the new ones. they are the palstic non-adjustable ones.
Good job! I want to try and develop some skills in that regard next time I have my carbs off.
 
just a warning if you get the repl solenoid from 4into-1, the wires have to be reversed to fit in the rubber holder, and it has no clip to hold in the top harness, in fact you have to grind it off in order to clear the green fuse.

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just a warning if you get the repl solenoid from 4into-1, the wires have to be reversed to fit in the rubber holder, and it has no clip to hold in the top harness, in fact you have to grind it off in order to clear the green fuse.
Interesting, obviously a generic version that is close but not exact.

You'll want to put a vent hose down to the bottom of the bike from that lead acid battery, the nipple and guide tab for the hose are right there.
 
yes, i know, its ll apart currently since the carbs are still out, have shove the airbox backwards still.
 
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