Topic: 70' ko project

[slyguy]

Hi folks..got a 70' ko original showing 7k but in very rough shape... I disassembled all but engine this past weekend but when degreasing frame today I found a rotted weak spot..

[754]

Looks like freeze damage..

[slyguy]

Looks like freeze damage..

yea, I have no idea? maybe it got water in the frame and then froze? now that you mention that, it is mushroomed up and does appear like a copper pipe might look after such a burst. My nephew in law is a welder, maybe he can weld it shut?

[70CB750]

I would find a new frame. Welding will probably require a sleve over this spot. The hole is just a part of a whole week section, welding it shot will only postpone the problem.

[Stev-o]

I would have a good welder repair it.....subscribed.

[slyguy]

Today I got my carbs cleaned up and ready for overhaul kits and I also need 1 float. I figure since money is very tight, I'll get some of the cleaning work done which usually gets rushed so a win/win for me:) not sure if I should paint carbs/polish bowls or what. Glad there's no rush. Lol!

[70CB750]

Is the float missing? I soldered leaky one sucessfully.

[slyguy]

Is the float missing? I soldered leaky one sucessfully.

no not missing, in fact the last carb/float even floated but had fluid inside so I'll be replacing 2 of them. I also need 1 gasket for the vacuum port screw and also the plate that connects all 4 carbs together, mine was cracked & previously epoxied which failed on disassembly.

[Tews19]

Should be a nice project. For any pics before the tear down? We all love pics!

[slyguy]

naw I forgot:( this is when I thought to get my camera...

[Garystratos201]

I vote for mig welding, you`ll be able to tell if its too rusty when they try to weld it. Im in for this one also...Gary

[Magpie]

I'm in, I love to watch! Cliff.

[lucky]

I vote for mig welding, you`ll be able to tell if its too rusty when they try to weld it. Im in for this one also...Gary

Good welders do NOT weld rusty metal.
A good welder would cut out that rusted section and find out what is going on because
the tubing is only .062 thickness. You will need to find out how much corrosion is going on. I would start by sanding the outside of the tube, (NOT GRINDING), and find out if the metal is corroded all the way through.

Then use a die grinder to clean the edges of the slot.
It is possible if the metal is good that a small patch can be TIG welded into that area.

By the way I would get the entire frame grit blasted and phosphate dipped to stop all the corrosion. You could just use phosphoric acid on it and then give it a good rinse. Dry and paint within 4 hours.

[Garystratos201]

Sorry Lucky I am aware that you do NOT weld rusty metal and that a patch has to be made. I  have been in the Collision repair industry for 43 years. I didnt list the steps because i figured that is was a given...............Gary

[slyguy]

Thanks guys for the tips! I took it over to my nephew in law who's a good knowledgeable welder and plan to pick it up in a week or so. Geez, I just finished going thru Mark's sandcast #97 thread..Whoa! and after reading alot of your threads I've been just doing some light cleanup of everything and moving it indoors for long storage. I just don't have the bucks available right now to do it right. I'm thinking it might be nice to at least go thru the engine this winter, Is it best to try to find nos gasket sets/seals or what?

[slyguy]

how do you guys go about the grubby battery box?

[Stev-o]

how do you guys go about the grubby battery box?

Ideally, sand blast and powder coat.

[hoodellyhoo]

how do you guys go about the grubby battery box?

Ideally, sand blast and powder coat.

just be VERY careful when removing the rubber bits. They can tear easily.

[slyguy]

I picked up my frame all fixed/welded:) and also got my "broken in 2 pcs" carbs plate welded this past week too. It's gettin cold rainy & even snow now.. making media blasting difficult but I'm getting setup for that hopefully soon. Still need to look into that phosphate acid deal too, sounds good but I'm thinking of rattle canning myself which would need to wait till spring/summer/warmtime..lol!

[MCRider]

I picked up my frame all fixed/welded:) and also got my "broken in 2 pcs" carbs plate welded this past week too. It's gettin cold rainy & even snow now.. making media blasting difficult but I'm getting setup for that hopefully soon. Still need to look into that phosphate acid deal too, sounds good but I'm thinking of rattle canning myself which would need to wait till spring/summer/warmtime..lol!

There was a group of frames that did not have weep holes in the bottom rails. They would collect water from up above, condensation and the like and end up with those freeze/burst/rust problems. Since you got it fixed, you should now drill the weep holes that the factory began drilling. I'll do a search for you. I know Honda Man has the location and diameter.

[MCRider]

Here's a thread on the subject. I searched on "frame drain holes". You can search further i got a lot of hits.

http://forums.sohc4.net/index.php?topic=105884.5;wap2

Here's another. The last pot in the thread is from HondaMan.
http://forums.sohc4.net/index.php?topic=109165.0

[slyguy]

Wow cool! Thanks MCRider!

[slyguy]

Geez, I haven't gotten much done...in a year! lol... Got a warm spell this weekend so I got out the pressure washer & cleaned up a couple sets of cases:) I had forgotten what tedious work it is scraping gaskets & cleaning motorcycles engines... I'm still wondering what to do with my output shaft/bearing. I could just reuse or...my old timer friend who use to run a repair shop for all bikes back in the early 70's and also specialized with building these for the street says to install the dbl row bearing but I think I would need another shaft too(outta a k2-k3?) but I won't be doing hole-shots or anything anyways.