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    Cannot retard ignition timing any further

    Just the top end
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    Cannot retard ignition timing any further

    Hi all, I'm having trouble getting the ignition timing correct on my '81 CB750C. It's firing way too early but I cannot retard it any further since I've turned the plate all the way already. What other adjustments can I make to resolve this? Thanks. Video of it running...
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    For Sale - DOHC swingarm bearing kit

    I bought this swingarm bearing kit for my CB750C but it didn't fit. The models listed are for '79 K and F but I think it should fit the rest of the gen2 years. It comes with 4 needle bearings which replace the brass bushings, a new collar and 2 dust caps. $100 plus shipping.
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    Starter Solenoid Help

    Thanks AMC. I should've been more specific with my question. I don't have access to the original harness so I can't tell which wire connected to which connector. Do you know which is the upper left, upper right, bottom left, and bottom right connectors? Would the circuit issues result because...
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    Starter Solenoid Help

    Hi all, I'm rewiring my '81 CB750C. I just got to the starter solenoid, which I assume is the original, OEM unit. I see the 4 male connectors go to the reg/rec, starter switch, ignition switch, and clutch diode but I'm unable to find out which one is which. Is there a way to test them? Does...
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    Exhaust Valve Leak After Top End Rebuild

    Thanks to all you wonderful people on this forum I've finally rebuilt my engine. I was super methodical to ensure I didn't make any more mistakes upon reassembly. Now that it's all together there are a couple issues I'd like your help addressing. First, the camshaft sprocket marks refused to...
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    Bearings questions

    Thanks AMC. I took the retainer back off and backed out the bearing on that side slightly. It seems to have loosened everything up so the opposite bearing now moves freely, the spacer moves, and the bearing that I backed out moves but it feels a lumpy. Does this mean the balls pressed...
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    Bearings questions

    Hi all, I have a couple bearing questions. I just installed my new steering stem bearings and I cant seem to get them seated all the way. I have the motion pro steering stem bearing driver and I'm whacking it as hard as possible but it won't go that final mm. What should I do? Should I freeze it...
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    Not getting cross hatching when cylinder honing

    Much better! Thanks AMC! I went with your pacing and it looks good to me..
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    Not getting cross hatching when cylinder honing

    Hi guys, I just tried to hone my cylinders but I wasn't getting 45 degree cross hatching so I stopped. It looks flatter, closer to 120 degrees. Why is that? Am I not moving the hone in and out fast enough? Or is the drill spinning too fast? Before...
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    cylinder base gasket - gasket sealant?

    Thanks for the advice guys. @AMC are these the ones you were talking about? https://www.harborfreight.com/12-piece-precision-needle-file-set-4614.html
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    cylinder base gasket - gasket sealant?

    Hi all, I'm about to reassemble my engine and I nicked up the base gasket surface. Should I use sealant in my specific case? I have some Hondabond but I was told its only for metal to metal surfaces? I also have the right stuff which I was told not to use with gaskets. Should get some gasgacinch...
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    What is an alternator carbon brush?

    Thanks AMC!
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    What is an alternator carbon brush?

    Hi all, I removed the alternator cover to polish it and "brush B" seems to have snapped off. What does it do? It seems like a switch or a button but I'm not sure. Is it sufficient to super glue it back on or do I need to replace it? Thanks.
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    Brake Master Cylinder, Rebuild or Replace?

    hi all, is there a strong argument for either rebuilding or replacing the OEM brake master cylinder on my cb750 DOHC? Thanks.
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    1981 CB750C Engine Rebuild Random Questions

    Yes, having read lots of your previous posts I have been super diligent about organization. I have a couple of 8 section bins already labeled for the valve pieces and I have the lifters and shims bagged up, all with labels. I have tons of pics and I have all the nuts and bolts in cardboard so I...
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    1981 CB750C Engine Rebuild Random Questions

    Hi all, if you've seen my other posts you know I started with inconsistent compression across all 4 cylinders. AMC kindly advised to adjust my clearances but digging a little deeper I found a leak in my cylinder 1 exhaust valves. I did a leak down test which confirmed that suspicion. So in...
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    Lobe position on valve clearance check '81 CB750C

    Thanks for all the help so far! So I don't have to worry about any other damage? Should I just proceed to order the required shims as I previously measured them and disregard the new lower clearances? I did measure each shim with a caliper and they were the same size stated on the shim so I'm...
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    Lobe position on valve clearance check '81 CB750C

    FFS, it was such a pain to get all the shims back in but they all look properly seated. I double and triple checked every one before turning the crank. After they were all in I rotated it a few times to check for anything hanging up and it all went smoothly. I went back and checked clearances...
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    Lobe position on valve clearance check '81 CB750C

    I don't think its bent. Clearances are the same. I would've had to go a full 180 degrees for all of the valves to be in the same position right? Have you ever had a tough time getting the shims back in? The tool keeps slipping and will keep one bucket down and the other will pop back up. I can't...
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    Lobe position on valve clearance check '81 CB750C

    Ok I know I’m an absolute idiot. I forgot the valve tool on cylinder 1 intake as I turned the crank 90 degrees. Are the valves definitely bent now? There wasn’t much resistance, I didn’t force it anymore than normal. 🤦*♂️ Also, can you leave the shims out as you turn the crank? I want to try to...
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    Lobe position on valve clearance check '81 CB750C

    Thanks AMC! No clue what I would do without your wisdom. So it's not an issue that the lobes are facing different directions? It shows 30k miles on the odo. Should I just go ahead and rebuild the top end since I have the engine out already? Is it worth several hundred dollars? I would have to...
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    Lobe position on valve clearance check '81 CB750C

    Hi all, I'm in the middle of adjusting the valves on my '81 CB750C. From what I understand the cylinder pairs are supposed to be in line with each other as you rotate the crank right? In other words, when the notch on cylinder 4, exhaust side, is at the 3 o'clock position, then cylinders 1 and 3...
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    Inconsistent compression across all cylinders CB750C DOHC

    Wow super informative! thanks for your help!
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    Inconsistent compression across all cylinders CB750C DOHC

    Hi all, I'm a new member here. With all this time at home I finally had a chance to get to a couple of projects. I just did a compression test on my '81 CB750C, wet, cold, and I got these results in, cylinder 1: 145, 2: 150, 3: 167, 4: 142. From high to low thats more than 17% so I know that is...
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