Topic: Concerns about rusted frame

[martin99]

Don't want to turn this into a powder coating thread - or upset the professional powder coaters out there - BUT -

This is exactly why you need to be wary of buying bikes with powder coated frames. Those drain holes often get filled up. I had one recently with a two inch split in the lower frame rail, completely undetectable when covered in PC and only found it when the frame was blasted. That split had to have been there before the PC.

I'm not against powder coating - just make sure it was done by someone reputable with knowledge of motorcycles and not someone who coats railings for a living.

[HondaMan]

I looked real close, no luck finding them yet. I sprayed a lot of CRC in the holes showin in the first post pix here, and it started to overflow out the same hole. I guess I will have to bring it out in the daylight this weekend and look with a mag glass.

You can always make your own (I have, several times on K5 frames). I used a small carbide ball on a Dremel, reached into that hole on the gusset plate, ground a little hole into the downtube, big enough to let the CRC spray tube in. Of course, on the K4/5, you also have to make the lower holes, because they were not there on most of them, Honda had gotten into a different mindset about the bikes by then.

[HondaMan]

Attached are pictures from my 72 CB750. 

I noticed the other day (while taking a brake from my other rebuild) there seems to be some significant rust on the frame around where the swingarm mounts.

The left side seems to have a little hole in the steel, and the right side has paint flaking off the welds.

Is this safe/normal, and if not is this repairable?

I was thinking about building this bike into an AHRMA race bike - not so sure now after seeing this.

Thoughts?

Thanks,
Chris

KS:
If you can't resolve the lower frame issue w/o replacing something, I have a K4 frame that cannot be titled here, due to a bizarre Colorado "once junked" law. You could cut the lower part off of it and weld it to your [legal] upper half?

[edwardmorris]

You can always make your own (I have, several times on K5 frames). I used a small carbide ball on a Dremel, reached into that hole on the gusset plate, ground a little hole into the downtube, big enough to let the CRC spray tube in. Of course, on the K4/5, you also have to make the lower holes, because they were not there on most of them, Honda had gotten into a different mindset about the bikes by then.

I guess I'll have to, couldn't find them.

Any thoughts on the Eastwood internal frame coating for rust containment?

[Powderman]

Don't want to turn this into a powder coating thread - or upset the professional powder coaters out there - BUT -

This is exactly why you need to be wary of buying bikes with powder coated frames. Those drain holes often get filled up. I had one recently with a two inch split in the lower frame rail, completely undetectable when covered in PC and only found it when the frame was blasted. That split had to have been there before the PC.

I'm not against powder coating - just make sure it was done by someone reputable with knowledge of motorcycles and not someone who coats railings for a living.

As a professional powder coater I have to comment here. Powder coating, when applied properly, will only be 1.5-3.0 mil thick (.0015"-.003") It will not fill a 1/16" hole (.0625"). It will fill scratches from 220 grit sand paper. It will not crack before the metal does so it it may conceal cracks in the metal. This is why in some drag race sanctions it is forbidden to have the frame powder coated. I would need your definition of a "2" split" as opposed to a crack. You are correct on only using someone knowledgeable on bikes and powder coating. I inspect each part for cracks and other issues after blasting where everything should be more visible.

[Powderman]

Attached are pictures from my 72 CB750. 

I noticed the other day (while taking a brake from my other rebuild) there seems to be some significant rust on the frame around where the swingarm mounts.

The left side seems to have a little hole in the steel, and the right side has paint flaking off the welds.

Is this safe/normal, and if not is this repairable?

I was thinking about building this bike into an AHRMA race bike - not so sure now after seeing this.

Thoughts?

Thanks,
Chris

KS:
If you can't resolve the lower frame issue w/o replacing something, I have a K4 frame that cannot be titled here, due to a bizarre Colorado "once junked" law. You could cut the lower part off of it and weld it to your [legal] upper half?

Would that technically be illegal? You would essentially be cutting the numbers from one bike and welding it to another. I know in some states that wouldn't fly though it would be hard to detect.

[edwardmorris]

You were right Hondaman, I drilled the holes today and voila, instant puddle. Details and pix in my build thread.

[calj737]

IF you hadn't gotten a puddle, it would have been the first time Hondaman was ever wrong... Or so it seems. The guy is the equivalent of the Fountain of Youth in terms of Fountain of Honda Knowledge.

[MoMo]

Attached are pictures from my 72 CB750. 

I noticed the other day (while taking a brake from my other rebuild) there seems to be some significant rust on the frame around where the swingarm mounts.

The left side seems to have a little hole in the steel, and the right side has paint flaking off the welds.

Is this safe/normal, and if not is this repairable?

I was thinking about building this bike into an AHRMA race bike - not so sure now after seeing this.

Thoughts?

Thanks,
Chris

KS:
If you can't resolve the lower frame issue w/o replacing something, I have a K4 frame that cannot be titled here, due to a bizarre Colorado "once junked" law. You could cut the lower part off of it and weld it to your [legal] upper half?

Would that technically be illegal? You would essentially be cutting the numbers from one bike and welding it to another. I know in some states that wouldn't fly though it would be hard to detect.

Yes, but what you have done is rebuild the bike with the valid title by replacing the back part of the frame and various parts.  I changed two numbers, but one would need an x-ray to see what was done...larry