Honda CX 500 Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
187 Posts
Discussion Starter #1 (Edited)
So after going to the PAC NW HTTA rally, I decided that I needed a larger fuel tank. With my bike being an '81 Custom, having a tank that can only go about 100 miles was just obnoxious - I want and need a larger tank so that I can go longer distances. Aside from a rae-san, my bike is stock and I intend to keep it that way, in that I don't want to chop it up and turn it into a cafe racer. I just want more fuel capacity, and frankly, I will say that I do like the aesthetics of the Standard/Deluxe tanks.

So I was browsing Ebay and stumbled into a fuel tank that was listed simply as a 1978 CX500 tank - I thought perhaps it was a "standard" so I messaged the guy and made an offer; no one bid on it, so after the auction ended, he sold it to me. $260.00 shipped. I think I scored, as it appears to be in really good condition! It has some scratches on the finish and a bit of rust around the fuel cap lid, but the inside looks pretty danged clean!













I'm thinking of repainting it, as the scratches on the one side are pretty significant.

Can anyone help me identify the correct model/year of this tank? Is it a Deluxe? I'm going to need to buy a new petcock for it and want to get the right one. I'm also curious about what I should do as far as the inside goes. As I was waiting for it to arrive, I watched all kinds of videos of people using muriatic acid and vinegar and bolts/screws and all kinds of stuff to de-rust and clean the insides of their tanks, but man, I just don't think this one will need it. Maybe just give it a good rinse with with a bit of diesel or gasoline? What should I do to get this thing truly road worthy? I'd also love to get the locked tank lid keyed properly. Any ideas there?

Any advice about this undertaking would be appreciated. It sounds like fitting a Deluxe tank to a Custom will require some modifications to make it fit, as well as a seat shortened in the front by about an inch.

I think this will be a fun project over the winter!
 

·
Registered
Joined
·
1,149 Posts
It is a 1978 model year. Only one style back then and only two colors. (In the USA) Here was my new one. Wish I still had it. It was a sweet ride.
203855
 

·
Registered
Joined
·
9,025 Posts
I think the '79 Standard had gold highlights on the tank graphics, rather than silver. I know the side cover badges were gold trimmed.
So, probably a '78.

P.S. I just looked at the old advert on my basement wall -- gold on the '79 tank.
 

·
Registered
Joined
·
862 Posts
The picture you have of the inside of the tank looks beautiful. I don’t know that I would do anything to the inside of the tank. If you don’t hear anything inside the tank while shaking it I would just put the new petcock in and go on a 150+ mile ride with no fear of running out of gas!
 

·
Registered
Joined
·
16 Posts
So after going to the PAC NW HTTA rally, I decided that I needed a larger fuel tank. With my bike being an '81 Custom, having a tank that can only go about 100 miles was just obnoxious - I want and need a larger tank so that I can go longer distances. Aside from a rae-san, my bike is stock and I intend to keep it that way, in that I don't want to chop it up and turn it into a cafe racer. I just want more fuel capacity, and frankly, I will say that I do like the aesthetics of the Standard/Deluxe tanks.

So I was browsing Ebay and stumbled into a fuel tank that was listed simply as a 1978 CX500 tank - I thought perhaps it was a "standard" so I messaged the guy and made an offer; no one bid on it, so after the auction ended, he sold it to me. $260.00 shipped. I think I scored, as it appears to be in really good condition! It has some scratches on the finish and a bit of rust around the fuel cap lid, but the inside looks pretty danged clean!













I'm thinking of repainting it, as the scratches on the one side are pretty significant.

Can anyone help me identify the correct model/year of this tank? Is it a Deluxe? I'm going to need to buy a new petcock for it and want to get the right one. I'm also curious about what I should do as far as the inside goes. As I was waiting for it to arrive, I watched all kinds of videos of people using muriatic acid and vinegar and bolts/screws and all kinds of stuff to de-rust and clean the insides of their tanks, but man, I just don't think this one will need it. Maybe just give it a good rinse with with a bit of diesel or gasoline? What should I do to get this thing truly road worthy? I'd also love to get the locked tank lid keyed properly. Any ideas there?

Any advice about this undertaking would be appreciated. It sounds like fitting a Deluxe tank to a Custom will require some modifications to make it fit, as well as a seat shortened in the front by about an inch.

I think this will be a fun project over the winter!

I just grabbed a 78 no where close to this clean and it has holes but all in all I paid 100 with shipping because it has small holes, rust and a few dents. Hopefully I can clean it up and swap my custom peanut tank. Besides all that yours is similar to the 78 I picked up with the type of cap and paint job.
 

·
Registered
Joined
·
16 Posts
I just grabbed a 78 no where close to this clean and it has holes but all in all I paid 100 with shipping because it has small holes, rust and a few dents. Hopefully I can clean it up and swap my custom peanut tank. Besides all that yours is similar to the 78 I picked up with the type of cap and paint job.
 

Attachments

·
Registered
Joined
·
187 Posts
Discussion Starter #9
Ahh, I appreciate all the wonderful replies! It was indeed listed as a 1978, but I wasn't sure if that had been accurate, but it sounds like it was! I'm super tickled. I went on Partzilla and ordered a new OEM petcock and some of the other available bits so that I can replace a few things on it and make it look all nice and new. It has deep scratches on one side that go down to the metal, so I think I am going to repaint it. I think I might give it a good scouring on the inside just to be safe - but not with acid, as I don't want to deal with flash-rust. I was thinking that I might get some marvel mystery oil and some screws/bolts/nuts and shake the tank around to dislodge any unseen bits and clean up the inner surface. I've read so many posts about how one little fleck of rust can jam up a carburetor that I've become a bit paranoid. Would that be a bad idea?

Again, thank you for all the replies! I look forward to extending my bike's range!!!!
 

·
Super Moderator
Joined
·
21,125 Posts
Have a look here.

 

·
Super Moderator
Joined
·
14,722 Posts
Don't use nuts & bolts to clean a tank, or gravel for that matter. Whatever you put into the tank to remove any rust that may be in there has to be removed when you are done and speaking as someone who spent nearly an hour getting a petcock strainer out I can tell you that removing a bunch of small objects would be incredibly frustrating.
If you must put something into the tank and shake it around use a length of chain. It will do the same job but when you are done you only need to remove one thing and it will be long enough for you to snag with a bent wire and pull out.

BUT whatever removes the rust will also damage the plating inside the tank that is there to help prevent rust from forming quickly (that's why cleaning with acid should be a last resort and only if you are going to epoxy line it afterward) so before you even think about anything like that make sure it is needed. If you can get an endoscope/borescope type camera you can easily inspect the deepest nooks & crannies of the tank. Failing that you could cap the outlet, pour in a cup or so of any solvent (regular gas would do), shake it around a bit and see if it comes out clean.
 

·
Super Moderator
Joined
·
21,125 Posts
I use chains and a telescopic magnet on a stick to recover them.

Nuts and bolts are a bugger to retrieve but OK if steel. They too can be retrieved with a magnet.

The last time I used nuts and bolts in a tank I grabbed a few fistfuls from the imperial dreck I have a large mostly useless stash of.

Several of the buggers turned out to be brass and a couple were aluminium.

The tanks inner lip around the filler makes retrieving anything not steel an exercise in pure frustration.
 

·
Registered
Joined
·
9,025 Posts
Based on your photo, I'd leave the inside alone. Scouring the tank by whatever means will expose the underlying metal, which could result in new rust.
You do know that you'll need to make some modifications to mount that on your Custom, right?
 

·
Registered
Joined
·
187 Posts
Discussion Starter #14
Thanks you all! I'll plan on getting a scope to check out the inner parts of the tank.

And yes, I do know that I'll have to make some modifications to make it fit on my custom.....sounds like I'll need to alter the rear mounting area of the tank, the side mounts on the Custom's frame, and possibly my seat as well. Good times!

I saw a pretty nice write-up with photos that the illustrious Larry Cargill posted, so I'll be consulting that when I go to get started.
 

·
Super Moderator
Joined
·
14,722 Posts
Thanks you all! I'll plan on getting a scope to check out the inner parts of the tank.
You'll find it useful for checking the camchain for wear too.
 

·
Registered
Joined
·
187 Posts
Discussion Starter #17
Thanks you all! I just went on Amazon and ordered one for $20, it seems like it'll be a handy thing to have around. Nolimitz and I replaced my camchain about 1000 miles ago, so hopefully I won't have to inspect mine anytime soon, though I have a buddy with a 1981 Custom whom I'm trying to convince to join the forum, and I will be able to use it to check his out.
 

·
Registered
Joined
·
862 Posts
Just my 2 cents here. I like to check where the cam chain adjuster is at before and after adjustment just to see how much slack needed taking up. If not much then I know my intervals for adjustment are good and I’m good to go. If a large amount of slack was taken up I know to adjust more often or I have a bigger issue to check.
 

·
Registered
Joined
·
6,808 Posts
Re: tank
Your new tank looks cleaner than mine. I know your concerned about bits getting to the carbs....
In my case the tank is fairly clean and I have not considered any interior work in the time I have owned it. I did one carb clean since I've owned the GL not because it needed it, just that I had no history on them and did it as a precaution. I do not have an inline filter either. I have never had an issue you describe with bits or rust.

IMHO leave it alone and ride your bike when installed. Just my 2 cents
 
1 - 20 of 21 Posts
Top