79 CB750K RCB Clone-ish. On the road.

Basement rat

Over 1,000 Posts
Starting new thread to appease the hoard ;)

Edited for the new guys. Look at the date stamps...







Is going to look half assed like this:


And currently planning a LONG term project with leaf spring rear suspension. Gonna put some actual figuring and mathmatiks ;) to it.
Re: 79 CB750K RCB Clone-ish

Talked to Sean, hes doing a little cad work before he starts pounding metal.

I have my tail on order as seen above from Germany because the place where its made in France wont reply to me emails...
Re: 79 CB750K RCB Clone-ish

To prove I haven't given up...

My digi-cam died on me so I had to use my lap top web cam.


I think I'm going to have my frame powder coated if I can figure out how to remove the nut on my triple tree...


The side covers on the engine will be getting polished and the valve cover will be getting a new gray paint job, a little different from the jugs.
Re: 79 CB750K RCB Clone-ish

You're back at it huh. Well if you can make your bike look like your inspiration pic then you'll have one sweet bike.Just stay focused. Whats the talk of leaf spring suspension?
Re: 79 CB750K RCB Clone-ish

With some words of encouragement form Kiley I set forth on replacing my head gasket...

The second bolt I removed fell in to the DOHC valley of death :eek:... I found it stuck half way down! and used the worlds single most greatest invention to get it out, MAGNET ON A STICK!

Removing my cam caps I felt one snap breaking the torque :eek: Fortunately I managed to remove it in one piece but it is cracked 75% through, Now I need replacements, Where do I get some?

Also, my cylinders have tons of carbon deposits, about three of my valves have a red ish tint to them... Bad? I'm thinking I can clean it within reason and put it all back together. I just need to get the bike on a good hot 300 mile highway run... Buellerr? Bueller?


Done for the night with a Bushmills Black at my side.
Re: 79 CB750K RCB Clone-ish

Now aren't you glad you did that? It look like the Honda part number for your caps are 203154-001. Bike bandit has them for $19 each. At least they still have 'em!

As far as the deposits, you might as well soak all of your parts in a tub of solvent while you have it all broken down and clean the crap out of of it all. Maybe even consider a soda blasting. Make it as good as new, and go ahead and re-lap your valves while you're in there. It'll all just be peace of mind for the future, and you can call it a nice fresh head job.

Good job man.


Go to Engine and Exhaust, and then click cylinder head cover.
Re: 79 CB750K RCB Clone-ish

I need the bolts that hold the caps on, but they have em! and the valve cover bolt seals too.

I don't know if this was a good thing... Now I'm thinking, "how much would it cost to bore out the cylinders and get bigger pistons..."

And to the jug gasket too for good measure...
Re: 79 CB750K RCB Clone-ish

Basement rat said:
I need the bolts that hold the caps on, but they have em! and the valve cover bolt seals too.

I don't know if this was a good thing... Now I'm thinking, "how much would it cost to bore out the cylinders and get bigger pistons..."

And to the jug gasket too for good measure...

If you're gonna do it, then do it now. It is a PITA to keep taking it apart and putting it back together. Not from a mechanical standpoint, but setting cam timing on DOHC over and over gets tedious. Go for it! It's only $$$!
Re: 79 CB750K RCB Clone-ish

Its a good thing I have my dads old 750 to ride, This is becoming a long term project VERY fast. Not a bad thing, Gretta wasn't done in a day.

Got any recommendations for big bore kits? I don't want to go messing with the crank, valves or cam.

What did you recommend for the carb's again?

Ahhh, the shocks... $$$$$



Its useless buying a new bike, most don't fit. May as well do this girl right... Even if it costs the same as a new one.
Re: 79 CB750K RCB Clone-ish

Dynoman makes an 823cc big bore that is bore only, no re-sleeve for $499.


About halfway down the page.

I would recommend flat slide Mikunis. The TM series. Jut get the same MM measurement, or maybe one size up from where you are now. They are a mechanical flat slide, and will give you that throttle crack that you want. Nice and responsive.
Re: 79 CB750K RCB Clone-ish

From 843cc to 945cc they are boring only. How far do I want to go keeping my top end stock?
Re: 79 CB750K RCB Clone-ish

Basement rat said:
From 843cc to 945cc they are boring only. How far do I want to go keeping my top end stock?

WEll, port matching is a must the bigger you go in bore. You can get away with it on a smaller bore, but in the bigger, you're almost defeating the purpose if you don't match the head for the bore gains. I promise you'll notice with the 843....Huge difference.

But if you know a machinist....
Re: 79 CB750K RCB Clone-ish


I pulled the jug/s? off and as well as I cleaned the engine, some sand caught under somewhere fell in to the case. I vacuumed off what I could but there is still some in there... Not what I wanted to have happen. Anyone have a clue how the oil system works? If I spray everything down with WD, could that wash to the oil pan where it can be removed?

The pistons are in good shape, no scoring at all, just crusty carbon on the top.

Oh, My chain tensioner, not the one that has the two screws in but the little guy at the front... Both the "rails" seem to have broken off the slide. I have found half of each side rail so far...

Woot ::)


Insead of building this engine, I think I will go over a 900F engine in a year or two up.

Ive used some cleaner to get all the sand down in to the belly pan, I will remove that later and clean it out. Sorry for all the big bore drama, I will just be ordering a simple ring kit and put everything back together nice and neat.

making a nice list on bike bandit.

thanks Kiley!
Re: 79 CB750K RCB Clone-ish

Oh man, you're going to want to split the cases again if you got sand in there. Even if you did get the vast majority rinsed down into the pan...there WILL be grains left. Those WILL find their way into the most destructive places possible.

More than simple splitting the cases, you're going to need to clean and inspect every part in there to make sure some of the little stow-aways aren't sitting on a horizontal surface or in a crevice just waiting to get swept into the oil system and transported to someplace like a main bearing or cam journal.

makes me shudder just thinking about it. Even one stray grain of sand will chew things up.
Sand........how did you get sand in your engine? man, I'm sorry to hear that.....
Re: 79 CB750K RCB Clone-ish

Soooo, Waiting on:

Bike Bandit:

Piston rings
Cam cap bolts
Cam chain tensioner

Dime City:

Steering stem bearings
Signal lights

Roc City

RCC custom tank

What it looks like now:

Every nut and bolt and spring that goes on is getting brushed by my brass wire wheel and applied with lock tight. My brackets and sub frame are all going on right now so its easier to keep track of all my parts.


Yes, I know my oil filter is on sideways, it helps with clearance right now.


What could have been a very very very very very very very very bad day...


You see it almost broke clean off, this is the cam cap bolt I was telling you about

Thing about powder coat. It rocks! My frame looks brand new and its a blast to work on and see, a real motivator! The catch is clearance... On alot of parts for example my kick stand... The applied powder on the kick stand and frame made for a VERY TIGHT fit. I used a rubber mallet, some axle grease and a punch in the bolt hole to get everything lined up. But its worth it! I will have a brand new bike when I'm done!

Also, next time I might see if I can have the frame acid dipped... Right now I have all this orange rust powder and sand falling out of the little crevasses and joints of the frame... Its gonna be hell keeping it clean.

I'm a strong advocate of ride when the roads are clear and to hell with rain but I think this will be my show/ good weather/ pavement only baby for a little while.

I'm clearly not done yet but thanks for the help everyone. Kiley, Cuz' of you I'm a better man/ biker for pulling my engine apart.
Re: 79 CB750K RCB Clone-ish

Shiny frame! Mr. Rat that looks fantastic!

Acid dip is probably a good idea too, I was just thinking the same thing regarding my 500, I bobbed the back portion of the frame rails and got a dusty gritty surprise.....
Re: 79 CB750K RCB Clone-ish

Working most of the day, all the little brackets are on the frame now, cleaned up the wire harness and re taped the most of it to look nice and new. I'll let the lousy pics say the rest.


And my favorite part of the frame... There's just so much shit going on...


That's where we are now.
Re: 79 CB750K RCB Clone-ish

Frame looks good BR. So you did pull your engine apart? probably a good idea. Cant wait to see what you come up with. I'd like to see the finish of the bolts after a brass wire wheel. I dont like the way they look after a steel wire wheel wondering if the brass one would yeild a different result. Keep it up brother.
Re: 79 CB750K RCB Clone-ish

They look brand new to me. Im guessing the brass wont strip the coating off them like the steel will. We will see tho...
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