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

Re: '81 CB750C Basket Case

I'm excited to see the seat you plan on using with the tank. That tank is tough with a capital T.
 
Re: '81 CB750C Basket Case

Silky, I make my own seats. Usually I can never find one that fits and has the look I want... or if I do, it's WAAAAAY out of my budget.
Sure I'd love a polished one from Rockcity or a fiberglass one for Benji or Airtech but if I can do it me-self, I figure the money is better spent on other things for the builds.
I used "The Works" to de-rust the tank, chased that with baking soda and water, then rinsed with rubbing alcohol to obsorb the moisture and final rinse with Kerosene. It cleaned up nice.... inside.
I then spent the rest of the night with a can of stripper and steel wool.
Here is the first coat working



Then was a little disgruntled to find I had my work cut out for me to get most of the way through...(in order)
Flat black
Brown oxide primer (THICK)
Grey primer sealer
Couple of sections with Bondo
Factory blue metalic
Grey factory primer



By the time I was removing the 5th coat of stripper, it was time to go to bed and hadn't even had supper yet so I called it a night. Still another coat or two to do, but it is coming clean, slow but sure.

 
Re: '81 CB750C Basket Case

I had to stop in to work so I thought I'd make it worth my while and took the exhaust head pipes to the sand blaster to get rid of the rust and that gives the remaining chrome a good texture for the high temp paint to grip onto.
Here is a "Before" of one of the cut off headpipes the PO left me to work with...



... and the four finished pieces after I got the sand blasting completed even saved the clamp for the cross-over pipe joint.



Then this evening I went back to the tank. 2 more stripper applications and the last of my coarse steel wool I am down to bare steel. (whew!)







You can see some pitting on the top and the various small dents. So I still have some work to do before priming it. All in all, I am happy with this CB900F tank considering it was only $75 shipped.
I have had good luck in the past getting dents out of a steel tank with my "Ding King". It's an aluminum beam version of the cheaper "Pops-a-Dent". Go ahead and laugh, I sure did!
When I got it for Christmas a few years ago, I shoved it under my work bench and forgot about it. But last year I got it out for the "Overkill" Suzuki tank that was in worse shape than this one and after some practice I got VERY good results.
Sure it will need a little mud to smooth it out but not NEAR as much as I would be resorting to with out this T.V. gadget.
Thanks to the late Billy Mays for convincing a family member this was a good gift idea. ;D

dingkinglarge2.jpg
 
Re: '81 CB750C Basket Case

Been checking back every day to see if there are any updates...pretty excited about that tank! I had one goofy question. For the tank, you used stripper and steel wool, why not sandblast? Is it a bad idea to sandblast gas tanks?
 
Re: '81 CB750C Basket Case

Thanks for the intrest Silky,
Theres a couple of reasons...
I don't know if it's valid or not but I've always heard from the car bodyshop guys sandblasting sheet metal is tricky, you can distort it because the sheet metal can warp from growing a fraction when the media hits it. Tanks are a little thicker than a car body and probably safe but I didn't want to take the chance.
The other is there was some heavy paint on this one and I use the sandblasting cabinet at work. I didn't want to get any grief for putting all that debris in our sand.

Now for the update, I have been slowly but surely working on the tanks dozen or so dents and got the majoriy of each one pulled to where it can be hidden with a thin coat of body filler. Last night I used my die-grinder and cut the lower side cover mounting ears off, then sanded the raw edge to match the lines of the tank. Looks much better.
Plans are to get this thing bondo'ed and block sanded then in primer this weekend then I can turn my focus onto the engine.
I also got all 16 of the valves cleaned up and ready to lap in the heads. There are a couple that the seats give me some concern so we will see if they lap in or will need replaced. I need to pick up my gasket set and then I can start re-assembly.
 
Re: '81 CB750C Basket Case

That tanks' looking pretty nice so far... Its a great shape too.
Lot of paint on that thing?
No need for aftermarket here...
 
Re: '81 CB750C Basket Case

Ha! I remember when I bought the pops a dent kit. My brother's car had been vandalized and had little dents all over it, so I tried to figure out a cheap way to help him out. I tried the can of compressed air and lighter thing. Didn't work for me at all. The pops-a-dent worked amazingly well! I was able to remove a lot of the dents. It almost made me cringe to crank down on the screw and see the metal pull out so far. After a couple of dents, that "POP!" got to be a pretty satisfying sound.
 
Re: '81 CB750C Basket Case

I'll see if I can get some decent "after" pics before the body filler. It really isn't the "scam" I thought it was from watching all the Billy Mays' comercials.
 
Re: '81 CB750C Basket Case

Fact: as a Paintless Dent Technician for almost 20 years I can tell you with confidence that those do it your self dent pullers will not work on anything creased or sharp and often will pull to far on soft dents leaving work to be done knocking the metal back down. If your close to Richmond Va stop in and I will work on it free of charge. Im nice like that, haha.
Regarding "who in there right mind would break down an engine with 15K?" I can tell you why I am. Caus it leaks oil like the exxon valdese! Ah but I cant wait til its done... :)
 
Re: '81 CB750C Basket Case

All very valid points AutoTek, thanks for the insight!
You and I already chatted about the paintless dent removal on motorcycle tanks. You are right, one of the tricks is knowing when to stop pulling so you don't have a "proud" high spot surrounding the dented are when you are done.
 
Re: '81 CB750C Basket Case

I got the dozen or more dents down to a manageable level and broke out the Bondo. I really am liking the "Premium Gold" as it speads and sands much better that the entry level stuff. After several light applications and lots of sanding, I've got it to where I can't feel the repairs.





Now that it's ready I can use my High Build Primer and give it a good sanding for final imperfections. Then if satisfied, hit it with the primer sealer and the tank and frame are ready for color.
You can see in the pics I cut off the lower ears for the original donors side cover mounts. I think it gives it a more finished look and wont give the completed bike an "I'm Sportin a Swapped Tank" attitude.
Speaking of bikes, I found this motivational pic on e-bay that referances DCC / Air and Iron. Not exactly my plan, but pretty damn sweet... I'm thinking similar style seat but thicker padding, my exhaust is going to be chrome turnouts instead of those huge cans, and I'll like my tank shape even better. So just like that, but different... Ya know? ;)

 
Re: '81 CB750C Basket Case

Im about ready for paint myself. My tank has to be stripped and the crappy liner removed then relined and then paint. wow that sounds like a lot of crap! haha good luck with yours!
 
Re: '81 CB750C Basket Case

After you get the old liner removed (using MEK?) take a look at the $50 mod thread for how to clean the inside of the tank. Unless there is actually some holes from pitting it may not need relined.
Got the primer on mine, shes turned out pretty good. I only see two small places that need attention.

 
Re: '81 CB750C Basket Case

Looking good! It was hard to visualize what it would look like with the side cover mounting tabs ground off.
 
Re: '81 CB750C Basket Case

You are the second person to recommend MEK so yes about two gallons please. Thanks HD
 
Re: '81 CB750C Basket Case

Autotek said:
You are the second person to recommend MEK so yes about two gallons please. Thanks HD
NASTY SHIT! so wear your PPE (Personal Protective Equipment) Gloves and goggles minimum, respirator if you are in an enclosed space.
 
Re: '81 CB750C Basket Case

Holy shit yes, MEK will take the white off rice D: Burns like a mother on skin, so keep a garden hose or bucket of water or something nearby. That stuff is as bad or worse than paint stripper!

That tank looks a lot like the tank on my '79 CB650 - did you have problems with the area where the badges screw on? I had a devil of a time getting primer and paint right there.

Nice build though - do you get an award for busiest bike builder on DTT? :)
 
Re: '81 CB750C Basket Case

I'm begining to believe this tank is from a CB750 K model, but still working on the year a 20mm petcock was available on..
And yes, it is a PITA to get behind the emblem mounts, brass brush, toothpics and compressed air.
Oh and Far from the busiest bloke on here, lets just say I'm an "active member" LOL!
 
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