Topic: 1975 CB750 stuck plugs

[Blair84]

Hello,

I've always loved these bikes and finally found a 1975 cb750 I'm working to get running by summer. This isn't my first bike/car restore but it is.my first CB750 and I will probably be looking on here a fair bit the next few months trying to figure this thing out. The bike looks amazing and had been garage stored since the mid 80s. From what I was told it had the engine rebuilt  a few years before being parked.

My first problem is the engine is seized, I thought I'd remove the plugs and put some penetrating fluids in to help break it free.

I was able to remove the outer 2 plugs with a  5/8 socket and they came right out. The inner 2 plugs use an 18mm socket and are stuck so I'm assuming they were also stuck 30 years ago or the plugs would all match.

Any tips on getting these out? I've put a lot of force on them but held back as I don't want to snap them off if there are any better options.

[pjandrew99]

The tool in the Honda tool kit is what I use. It is especially good for 2 and 3 which can be difficult when using sockets.
You can probably get a kit on Ebay.

[ekpent]

You can never go wrong by starting out with penetrating oil and heat combined with patience. If you can get them to slightly break loose keep the oil going on and tighten then loosen back and forth a little at a time and not all at once. Scary getting those stuck things out for sure. Good luck.

[HondaMan]

When you turn over the engine, DO NOT use the big nut by the points. This WILL bend the spark advancer's shaft behind it, and can even break it off. This part, and its seal, is unobtainium today.

Remove the alternator cover, instead, and use the bolt head on the rotor. This will also require you remove the tranny cover on that side.