'81 CB750C "Rock-It" (X-Basket Case)

Re: '81 CB750C Basket Case

Scuffing small sections every day got the job done.... yesterday when I go off work it was still 104 degrees but I stayed out in the shop until it was finished. Really wanted it ready for the self etching primer this weekend. All thats left it to wipe it with down with mineral spirits to remove any dust / debris / oils then hang-n-shoot



The reason for the primer goal is I am off work next week the 4th thru the 9th and want to get the color coat on. Whatever it may be. Was thinking hard about red but silver would allow for so many more tank color choices.
By then the NOS Mac mufflers I scored off e-bay should be here, and I can play with the remains of the factory head-pipes the PO hacked up to come up with a 4 /2 exhaust.

 
Re: '81 CB750C Basket Case

Guess who's to blame for ending the 9 week drought here in northern Indiana?
ME that's who!
All I had to do was buy my self-etching primer and it rained Friday, Friday night, Saturday and just now on Sunday... JEEZE LOUISE.
No problem really, I was able to get 4 coats on today before the short storm blew in this afternoon.

 
Re: '81 CB750C Basket Case

I'll keep an eye on this. I'm looking to buy a project in the near future and was thinking about a SOHC 750 but there are a lot more of the DOHC Hondas about these days. Much more reasonable prices too.
 
Re: '81 CB750C Basket Case

Yea, they are kinda under the radar compared to their older sisters... but the aftermarket kinda follows suite. Much more stuff available for the more popular models. Don't know whats to become of this quite yet, but glad you're along for the ride!
 
Re: '81 CB750C Basket Case

Nice one HD! That sounds like when I painted the 450... took a week and a bit off work and ended up racing the rain for half of it...
 
Re: '81 CB750C Basket Case

Yea I remember that one Pete. Your holiday from work didn't quite turned out the way you planned. ;)

My E-bayed MAC mufflers showed up today. Giddy as a school girl when I opened the box and saw all the bubble wrap. I wish new products were packaged this well! They look GREAT, truely N.O.S. only small nicks here and there and will look great on the bike. I grabbed one of the head pipes and they are the same diameter so I will need to make up a slip on adapter of some sort... minor issue.
When I logged into my e-bay account to leave the feedback I saw a '81 CB900F tank I was watching was ending in 3 minutes, no one had bid on it so I bought this for $50. That plus the shipping is almost EXACTLY what I had in my Pay-pal account, so I figured it was an omen. Even if I can't make it work I can clean it up inside and out, straighten the dents, and shoot a decent coat of paint on it and double my money. "Estimated delivery within 6-15 business days"
COME TO DADDY!!!



 
Re: '81 CB750C Basket Case

Turned my attention back to the engine, specifically the cylinder head. A while back I had disassembled it down to just the valves in place and gave it a good bath in the parts washer. With quite a bit of reading here I was trying to decide the best valve spring compressor to get. Didn't want to spent close to $70 if I didn't have to so searched for a DIY idea.
In the past I had welded up some steel rods and washers to use my C-clamp..

...but it was too large to fit inside the recess where the springs and buckets reside. I was also worried about marring up the aluminum bore.
Searchin www.CB750C.com I saw where a 35mm film canister was used to protect it. But I haven't see one of those in a decade! Then I found where a member Frank had my solution and located some scrap 3/4" PVC pipe I had that was just the right diameter.
Cut a notch in a small piece and I had my adapter...

In the past I was also worried about marring the face of the valve and had found a pop bottle screw on cap fits the pivot foot of the C-clamp. So now I was all set.

With the cylinder head blocked on its side, I gave it a test and badda-bing badda-boom it worked like a charm. Very easily compressing the springs.

Used the notched section to reach in with my magnet and out came the keepers and with the notch about a 1/4 of the diameter I had enough room to work.


This little tool is friggin slick! The only real additional input I'd give is to make sure you get the length right. You want it and the notch long enough so you still have room to work when compressed, but short enough to give you some slack once the spring tension is completely released. Also, when you use it, to put the "window" opposite of the cam journal adjacent to that valve to give you the most room to work. Next, be sure once you have the springs out be sure to remove BOTH of the steel seats. Most could be pulled out with my magnet, but a couple were held in by the surface tension of the oil under them. Put the magnet back in and using a rubber tipped blow gun and a quick blast of air loosened them so my magnet could grab them. PIECE-O-CAKE!
 
Re: '81 CB750C Basket Case

That's a really nifty trick. I like it when I see tools that almost anyone can build on their own.
 
Re: '81 CB750C Basket Case

Nice one HD! That's the same trick I used on my 450 after viewing Steve's video of it over on the GSR.

The only trick to it is making sure the PVC pipe has thick enough walls. The stuff I used was a bit thin and tended to warp when you got the spring really compressed. It held up enough for all 4 valves though ;)
 
Re: '81 CB750C Basket Case

Hey john83, read enough of my build threads and you find I am a cheap bastard. If I can make something out of shit I have laying around VS buying something... it's a no brainer. :)

Good point Pete, I should have mentioned it's standard schedule 40 PVC... not the thin wall schedule 20 shit they sell for kitchen and bath drains.
 
Re: '81 CB750C Basket Case

man, that is a smart score! re-assemble, flip for $1500, and purchase feather bead frame Sir! :) sorry, somebody has to play Devil's advocate... I dig that job.
 
Re: '81 CB750C Basket Case

Ooohhhhh a Norton Featherbed Frame.... and Vincent motor... build me a Norvin.
SCHAAAAWING!
 
Re: '81 CB750C Basket Case

Last night when I arrived home from work the tank was waiting for me.
Better than I expected. Even tough the add said it would be a bare tank with all items removed, only the petcock and the locking latch for over the cap was missing. It still had the cap and emblems on it... and the inside just has some slight surface rust. BONUS!
I put a cork in the empty petcock bung and gave it a quick wash job to test fit it on my primered frame. Having read posts on the CB750C foum that the mounting points on the frames and tanks between the C, K, and F model are indeed different and it would require modifications to fit, I was concerned. But when I put the rubber front cushions on the frame posts and lowered the front tank mounts on the fit was just right. Then lowered it onto the rear mounting bolts position...





Now I am not going to run the stock seat, and obvious by this picture the OEM side covers would be an issue as the "C" and "F" models attach in different points.



So I think I got a "winner". I am planning to trim off the side cover mounting ears from the tank which I seen done and cleans it up a lot. In the first pic of the full side shot, the tank looks way big, but that's more of a camera angle... In person it looks propotioned pretty damn good to me.
 
Re: '81 CB750C Basket Case

That looks pretty good. Good to know that an F tank will just slide onto a C bike.
 
Re: '81 CB750C Basket Case

Yea, I'm pretty stoked! I read other places that the 900C tanks from different years won't interchange even on other 900C's. I am thinking it helped that they were both '81s. Now there appears to be plenty of room for the petcock and engine clearance.... guess time will tell on that part of it. ::)
 
Re: '81 CB750C Basket Case

signed in. how do people have these bikes fall in their laps? at least you know what to do with it. can't wait to see more
 
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