Cracked Head Pipe

[Coyote]

This left pipe is trash. I certainly did waste my time patching the big rust hole in it. Only to find this.

[Coyote]

Do you think it will work OK this way? The crack is very tight. I really hate to dump more money in to the bike till I make sure it's gonna be a runner. The center pipe is a rust bucket and may eventually need re-chromed. Is there a product that will dissolve the carbon in the pipe? It's not oily at all.

[pearljam724]

I must be missing something. I looked closely at all pics. Couldn't see any crack. I see what appears to be a very long parallel scratch. My pipes have that too. The more you ride the bike and the pipes vibrate over time. It will increase in size if you have a crack. Seafoam works fantastic at removing carbon. Just use a plug at one end and poor it in and slosh it around for a few days. I would suggest a couple cans at once. The longer it sets, the more it removes. It needs to set more than a day. Fantastic video. Watch the part near the end with the Seafoam sitting on top of a piston. https://www.youtube.com/watch?v=WdT4DPF ... wl8s6DKBww" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[Coyote]

It's definitely a crack. If you look at the first and second pic, you can see the rust bleeding out of it. Just brought the right one in to work on it. It's cracked as well but not as severe as the left

[Coyote]

The left inner is in great shape. It was protected by 18lbs.of 2-stroke muck.

[ConnerVT]

Well, you could always just wrap them with header tape.

[Cliff]

Checked a set of pipes I have in the garage and they have the same marking. Could be a seam in the pipe or a mark left from the die when the pipes were bent.
Here's a poor man's magnaflux check for cracks. Soak the pipe end with the "crack" in a 5 gallon bucket of water over night. Take it out and dry it it with a rag. Don't use compressed air or heat to dry it, just a rag and let it air dry. Spray the "crack" with red oxide primer or sprinkle it with baby powder as you heat it with a propane torch or heat gun from the underside. Don't apply heat directly to the "crack"!! If it is a crack, a line will show up in the primer or powder! Metal is porous and will hold the water. When the pipe is heated the water will be forced out and show up on the surface as a crack!

[pearljam724]

I agree with Cliff. Not saying you don't know what you're looking at Coyote. I can see how that would raise your attention. But, my pipes have the same exact marking on each of them and I know mine aren't cracked. Both my 550 and 750 pipes have that marking. If a pipe would crack. That is a very awkward direction for them to crack. Especially knowing how dense the pipe is in that area. On top of that, you're saying more than one is cracked the same. Another test would be to hit a tiny spot on that line with a grinding stone to see if the crack penetrates.

[CBWELLS]

IF that is a crack (& you may be right), I doubt it will effect anything at all. You ask if it will work. Sure it will work. Why not? It was apparently working last time the bike was operated with it. Besides, you said, "hate to dump more money in to the bike till I make sure it's gonna be a runner." So be creative (like the patch job.... looks good to me!) Put the pipes back on the bike when your ready & run it for a while. There's always time to spend money on it AFTER you decide! It's easy enough to change later if that's your choice.

Side-bare story: I had an Uncle who operated a junk-yard for most of his life. At a late stage in his life, he had a ratty, beat-up BMW bike with really rotted out header pipes. Being way too loud to tolerate, & being the creative & resourceful (not to mention, CHEAP) guy he was, he spiral wrapped the entire length pipes down to the muffler with wire, then brazed the valleys between the wire-wrap full of metal. Probably added 30 pounds to the bike, ....& talk about UGLY....WOW! In any case, it worked. I think yours will be just fine.

Have fun.

[Coyote]

We did a lot of dye checking where I worked. I have a can of penetrate and a can of developer. I'll check the most obvious tomorrow. Total time = 10 minutes.

[pearljam724]

Aside of polishing those pipes with a solid compound. Using a very fine steel wool pad combined with a chrome liquid polish first will bring those puppies to life. They sell different course grits of steel wool at any automotive store for a few bucks. A very fine or super fine grit will shine them up nice without leaving scratches. If you follow with the solid compound on a variable speed drill.

[Coyote]

50% of the materials we used for machining were subject to a crack check at finish. This method is known as Dye Check. We use another more accurate system called ZyGlo. It used a green penetrant and a black light. Some metals were subject to magnetic-particle testing. We did not have that capabillity so that got farmed out.


This is how it works. There are 3 steps. Cleaner, penetrant and developer. I don't have a can of cleaner but I know from years of use that's it's nothing more than a fast eveporating solvent. I will use acetone.
After cleaning the penetrant is applied. The penetrant has ultra high capillary action. It remains on the suspect surface for 8 minutes or longer.



So I have cleaned and applied the penetrant. The next step is to remove the penetrant with DRY paper towels. Dry it well till all the red is gone.

Then spray on the developer. It's nothing more than a wet talc. If there is a crack the red will bleed out almost instantly and indicate the crack. It will not show scratches as they don't absorb the penetrant.
Well my developer went bad and wouldn't spray. So I used a misting of white paint. Not the most absorbing thing but it was handy. Those my friends are cracks. They would hace been much more pronounced if the developer had worked.

[CBWELLS]

Call 'em cracks if ya like, but what's the implication? So....do ya use 'em or heave 'em out? Guess that depends on how deep your pockets are. Judging by the fact that you went to the effort of patching the muffler, I'm guessing your pockets do have a bottom that's detectable. I'd also venture a guess that there's not a 70's vintage pipe in existence that doesn't have some degree of "crack" like that... & I really doubt that any of the GT series are flawless. They were probably processed at the same plant in the exact same way & are subject to the same results.

Nobody can make your decision for you, but personally, I wouldn't worry about the "cracks"....at all. Ride it & enjoy it for what it is.

Keep the faith. I love to see these "old girls" still runnin' down the road.

Have fun.

[Coyote]

I plan to use them just the way they are.

[johnakay]

its a pity you didn't live near me as I would have fixed them for you.
its hard to tell if its a crack or the seem making it look like a crack or split.
seeing that you already have a welder,what I would do to make sure ...
is ti drill a small hole big enough to get a knife blade into and try and force that crack open.
if it is a crack drill another hole at the other end and 'V ' grind down the crack and tack weld it or better known as stitch weld.
don't go right through it though just enough to get a decent weld.
them dress it off but leave a little weld on top ..just a little proud thats all you need.
with any tubings it always try to straightened itself out of course we know it cant but as you'll already know its called stress .
this will if you like attack the weakest ..