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1978 CB750A, bringing it back..

I was able to get it off using penetrating oil and working it back and forth. I got enough room I was able to get increasing sized prying tools underneath and tapping the shaft with a brass hammer until I got it off. The rest of the unit should come off once I remove the cir-clip. I decided to soak everything in metal rescue overnight to kill the rest of the rust in the unit before I damaged one of the smaller pieces prying on it. I've started from the rear of the bike working forward after I did the carbs and this bike is going to take some work. I had to drive the swingarm bolt out with a brass hammer because it was frozen in there as well. Gotta love this brass hammer, I can beat the crap out of a threaded end bolt and put the nut right back on...no damage.
 
While that is true MOST of the time be aware that with excessive force bigger brass WILL bend thinner parts like steel threads................after base material the cross-section mass rule applies there......................luck. Aluminum drifts will the same way too. BTDT.
 
True amc49, but in this instance with the force needed to get these locked up pieces apart I'm willing to risk it. The block of wood was getting destroyed..
 
So further along now. Frame is painted and sitting patiently in the back. I'd like to order tires and get a roller going but I ran into valve problems and have to finish the engine first. had the head done and needed two valves and all 4 exhaust guides. on.http://www.cb750.com/attachment.php?attachmentid=8100&d=1510540233&thumb=1&stc=1
Ordered cam chain, guides and new rings and have been getting things ready to drop the top end back.http://www.cb750.com/attachment.php...?attachmentid=8098&d=1510539999&thumb=1&stc=1
 

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Hey guys, been away for awhile and wanted to catch up. Went out of town for 8 months for work and since my return have worked diligently trying to get back on top of this bike. did a bunch of my own paint and powder coat and doing well on the re-assembly. I'm kinda amazed I was able to remember as much as I have about how things went back together.80%.JPG.
Only issue I'm having is remembering how to mount the high idle solenoid. I see how and where it needs to go on the diagrams but can't seem to figure out the small bracket placement. anyone got a pic of where it goes??
 
Bringing this up to speed.work and other commitments have delayed progress but working diligently to get things done. Every time I take one step forward I slide back one. Wiring is complete, everything is back together. Put gas in the tank and crap! Damn thing is leaking. Found two pinholes and an issue with a seam so I ordered some POR-15 and coated the tank. While trying to start it I had a nasty noise and ended up shearing four teeth off the reduction gear. Got another and back at it. My problem now is it fires fine with starter fluid but while waiting on my tank cure I used an IV bottle and can’t seem to get the damn thing to fire with gas. I’m suspect of gas getting to the bowls but how can I check that with out pulling them off? The other issue is I’m wondering about the timing, given the kickback that broke those teeth. Like I said, fires and runs on starter fluid but that only lasts for a second. Trying to post pics
 
If you had any gas in it before it sat for a while good chance its gummed up again. There should be some bowl drains you can open to see if there is fuel in the bowls. How did you set adjust timing to begin with??
 
If bike ever ran well with the timing in it before I suggest not messing with it. If not then dive in. The reason being timing does not simply 'go off' if it was close enough to run well before. Maybe points need a bit of alcohol cleaning.

Another reason is that if the 'kickback' that damaged things came while using ether starting fluid that can easily do it and especially if the shot was too big done in frustration at engine not starting up.

Ether will crank anything but it is VERY finicky and can bite hard. It can catch piston going up to shove it backwards violently. NEVER use a longer than quick 2 second max shot and NEVER shoot again if the engine hasn't seemed to light at all on the first shot, it accumulates and how the big bangs happen next. If an engine does not start or pop off to show it ate the ether it has something mechanically wrong with it and in any case I for one will let engine then sit for at least a couple hours to let the ether dissipate. Then you can go again. Whirling engine over with starter and no coilspark can speed that wait up. It helps the ether to fully vaporize to then pump out but now it is in the pipe, give that some thought.

A very useful tool but you have to think before using it. No insult intended there at all of course.
 
If they use ethanol in your local fuel and the fuel in tank has sat at all I would suspect it too. If cloudy looking it has already phase separated and is bad, it will not start easily on that at all. May well even have water around the jet entrances. And like that it sticks float needles like you won't believe.
 
I agree with these guys. drain your tank and carb bowls. use fresh gas. See if your symptoms change. btw, did it start with ether, or just let off a loud fart? Switch the yellow and blue wires if it was the latter of the 2.


 
OK guys, thanks for the replies but let me clarify a couple of things. First startup since the engine rebuild. Starts righ up with the ether but dies as soon as it burns off. I get the kickback trying to start it with gas from an IV tank. My regular tank won’t be cured until Tomorrow because the POR product wants 96 hours to cure. Also first time gas has been introduced to the carbs since they were rebuilt as well. New coils, points and condensers and have a nice blue spark. I loosened the points plate to see if it may have been advanced too much and when I turned it all the way to right(retard?) it acted like it wanted to run but just wouldNot go. I wondered if I may have missed by one tooth When I installed the new cam chain during the engine rebuild but I if I had done that it wouldn’t have started at all correct?
 
is your iv tank vented? if not you very well may not be getting fuel to the carbs. You need to do some checking on your ignition timing, if your just cranking it around to try and get it to start then thats why you got kickback...ignition timing is off. Ignition timing is not affected by the cam timing being off as the points run direct off the crank. you need to get your base timing close. I have used test lights and analog volt meters. Then as Medyo suggested make sure you have the coils firing on the right set of cylinders. If you are having second thoughts about your cam timing then you better verify it
 
Coils are firing on the correct cylinders, I already verified that and I remember when I set the valves everything worked out OK. As I said I loosened the points plate and turned it all the way to the right and things appeared to smooth out. I just have a hard time believing it’s that far off. I guess I’ll turn it some and reset the points to see what happens. DD the IV tank was open on the top so I can’t see that not being enough vent. My tank will be cured tomorrow eve (96 hrs) so I’ll give it a shot with a tank full of gas to see if gravity helps me out any. It didn’t seem like much gas was flowing through the tube with the IV bottle. Might not have been enough weight to the gas to make it flow. I dunno. I’m so close and this project has thrown curves and sinkers at me the whole way. That’s what happens when you take on something that broke down and sat under a tarp outside for 22 yrs. another question. On the carbs there are two barbs. Obviously the larger one is the fuel and the smaller one being a vacuum. What hooks up to that vacuum barb?image.jpgimage.jpg
 
Small temporary fuel tank work fine use them all the time doing tune ups. I have also just left the hose open and filled with a small squirt bottle and filled it constantly. Will run fine without using the fuel tank. Are you talking about the part sticking out of the side of the carb in your picture?? if so nothing goes on that. There should be one vent right next to the fuel barb. Leave it open and put a hose on it, it has to vent to atmosphere.

Turning the plate and trying it isnt going to work. Get a test light or an analog volt meter and set your points so it comes on right as the f mark comes up on the advancer. Dont guess, adjust it right then you know.
 
Got back into the project today and the tank does not leak, I checked the timing it is spot on and the advancer weights are free and working. I did pull the plugs on the carburetors to make sure there was gas in the bowls and they leaked out of everyone but number four. I put a piece of fuel line against the drain hole and blew a little bit and gas came out of the other three carbs so I know the inlet is free so what could be the problem?
 
Ok pulled the bowl off carb #4. Must have been a stuck needle. Bike starts and runs with a little throttle and full choke. Take the choke off she dies but I’m getting a little closer. Anybody got a suggestion for my next step as far as lining out the choke having to be on?
 
its easy to get stuff sucked in and gas goes bad easy and easily restricts the idle jets. if your not using an inline filter it probably got something sucked in there.
 
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