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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: kennybobby on September 06, 2016, 04:58:50 PM

Title: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: kennybobby on September 06, 2016, 04:58:50 PM: Be sure to thoroughly inspect the fuel tank before you buy an old k bike--look for discolored paint bubbles and blisters along the bottom edge and seams as these are pinhole leaks just waiting to burst. Thank your uncle sam for the wonderful ethanol fuel and the blessings it brings to our daily life...

i should have known better than to think this this bike was ready to go riding, but i found out the hard way--now it's a whacked tarbaby with plenty of issues.

First is what came out of the fuel tank--a mixture of fuel, water, organic and inorganic solids. According to the whirled white websticle there are three basic areas of concern in fuels and oil: water, in-organic debris (sand, dust, rust, etc.) and organic debris (fuel breakdown products and waste products of fuel deterioration and re-polymerization). The organic debris represents more than 90% of all the contaminants found in fuels and oil.

Inside the tank there were patches of debris still clinging to the surface, these were vacuumed out and then scrubbed with sandpaper and a steel toothbrush later:

Now the pits were found growing in little farms on the plains, and pinholes were probed and plowed open with an ice pick:

So much for trying to save the paint job:

i'm leaning toward epoxy fill the holes from the outside, then redkote or some polymer to paint over and fill the interior pits and seams and cover the epoxy.
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: Bill on September 06, 2016, 08:45:09 PM: I've been looking into how I might refurbish a tank with the same problems and saw Damon Red-Kote available at O'Riellys'. Might be a solution for you @ 35USD a qt. I would have to import as the CDN distributor doesn;t stock.
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: billday on September 06, 2016, 09:52:30 PM: People part out K's -- maybe you can find a replacement tank. Besides Ebay and Beemer Boneyard, try http://marketplace.ibmwr.org/
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: Martin on September 07, 2016, 03:10:28 AM: I bought some aluminium solder, tried to solder using a propane torch with no success. When I get a chance I will try it again using oxy acetylene which might be more appropriate. I believe if I can master it should work well on tanks, has anybody tried soldering aluminium?? :dunno
Regards Martin.
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: Laitch on September 07, 2016, 10:00:10 AM: Quote from: Martin on September 07, 2016, 03:10:28 AM
I bought some aluminium solder, tried to solder using a propane torch with no success.
Try using Mapp gas first. It's available in small tanks.
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: jay1622 on September 07, 2016, 04:11:09 PM: I ended up having my tank welded at a radiator shop, and then I used the Damon Red-Kote. I cleaned mine with boiling hot water mixed with Dawn dish soap and a handful of painted carpenters nails. I shook it for, quite literally, 30 to 40 minutes. I drained that and left the screws in there and did the same thing with vinegar. After that, I left the vinegar sit for about three days and then shook it some more. I cleaned it out as best as possible, and dried it with heat and then some acetone. There is a ton of nooks where the Red Kote needs to get to, so cut it with acetone and keep mixing while taking peeks to see that you're getting adequate coverage. Apply regular shots of air (very low pressure) to the baffle output port to make sure your baffle is not getting clogged with the product. The fumes will have you high as a kite so do everything you can to mix it outside and with a breeze or strong fan. The fumes are also extremely flammable. I'll say it again, extremely flammable. If you use it, you will see the fumes pouring out, over and down to the floor. No kidding. It took mine about three weeks to dry; until there were no longer any fumes (Trace fumes at that point).

Edit:
Cap-off the inner tank ports with appropriately sized wire closet shelving caps; or something of that sort.

Edit #2:
Use of high concentrations of ethanol will strip the red dye from the dried product, FYI.
http://damonq.com/techsheets/red-kote.pdf
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: Martin on September 07, 2016, 04:25:09 PM: +1 Laitch will give it a try.
Regards Martin.
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: Brad-Man on September 07, 2016, 06:08:57 PM: People on another board swear by Caswell's tank sealer.

I would try MAPP first and then the Caswell's...
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: kennybobby on September 07, 2016, 07:13:40 PM: Thanks Jay, a buddy of mine used the redkote and said the acetone fumes attacked the paint around his fill port. He recommended to cover painted areas that matter and use a fan to clear the fumes also.
Title: Re: The Pitfarm of older bikes, thought it was a rider-- now it's a project
Post by: Bill on September 07, 2016, 07:43:24 PM: Quote from: jay1622 on September 07, 2016, 04:11:09 PM
I ended up having my tank welded at a radiator shop, and then I used the Damon Red-Kote.

Quite the task but are the results worth it ? In the read it suggest that pinholes of 1 mm can be sealed, have you used the tank since without issue ? I was thinking JB weld outside and red-kote inside as my subject tank has only oinholes.