Hi there, so I just bought a parts bike a 79 cb750f to be exact. The PO told me it ran before it sat but I wanna be sure the engine is good before installing into my project. I tried to turn engine from the right side generator nut and I'm going clockwise and get halfway then it won't turn anymore! Is this normal to do so? When I turn it counter clockwise I get almost a full rotation, I just want to make sure the engine isn't sized. Another issue is I checked the oil dipstick and it had some grey sticky stuff coming out on the stem? What could that be? And would would be the best plan of action to flush the engine?
Need Advise Cb750 DOHC
- Thread starter CafeBlack
- Start date
ApriliaBill
Yeah...I'm old school.
The gray crap is water mixed with the oil. You'll want to change that, several times. Learn basic engine. Spark, fuel, air. pull the spark plugs and get some light weight oil in there, let soak over night, then see if you can get some rotations on the bike. If you can, get a battery set up and see if your getting spark. From there it can go in many different paths. Is the timing right? What condition are the carbs in? Compression? "It ran when I parked it". This can mean many things. I didn't want to pay $600 in repairs on a $1,000 bike. I'm an idiot and didn't realize how easy it is to change a battery. I couldn't do a $20 oil change and seized the engine. I have bought many "it ran when I parked it" bikes and everybody here knows I'm no brain surgeon, but if you start with the basics, these fine gentlemen can talk you through it...
barnett468
Coast to Coast
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the cylinders are not seized, however since it had water in the oil and it doesn't turn all the way over simply take it all apart and repair as needed.
remove the clutch cover and make sure the shift drum is in the neutral position . . if it is and still doesn't turn over, remove the clutch basket and try to turn over the crank then the trans . . one of them will not turn over all the way . . the one that doesn't is where your problem is.
it is possibly a cam that is out of time because the timing chain jumped a few teeth allowing the valve to hit the piston.
the cylinders are not seized, however since it had water in the oil and it doesn't turn all the way over simply take it all apart and repair as needed.
remove the clutch cover and make sure the shift drum is in the neutral position . . if it is and still doesn't turn over, remove the clutch basket and try to turn over the crank then the trans . . one of them will not turn over all the way . . the one that doesn't is where your problem is.
it is possibly a cam that is out of time because the timing chain jumped a few teeth allowing the valve to hit the piston.
