Crushed inner header pipe

[Mike E]

Has any of you ever heard of this ? My 1985 Honda ATC200m would not rev up past idle. I checked the muffler carb tiiming valves and could not figure it out . I bought another 200 and was cleaning it up and doing some painting and when I got to the pipe I had already repainted the pipe off the 200m so to save down time I put the 200m pipe on and guess what it would not rev up. The problem was that the header pipe had collapsed on the inside just past the curved part . Is this rare or should I expect it to happen again ? Thanks! :?:

[Howdy]

Must be rare. I never heard of that one before. I doubt you need to worry about it happening again.
Just my 2 cents.

Howdy

[lushatc200x]

id say you hit something hard real hard

[Mike E]

The pipe looked normal on the outside it was only collapsed on the inside. No outer damage at all.

[lushatc200x]

on the inside how wouldnt that affect the outside im not understanding i dont guess :D

[Mike E]

Ok I've cut the pipe in half and here are some photos.

[Billy Golightly]

I noticed when I was modifying the 350X exhaust to go on my project 500X that the exhause tubing was twin wall, as is yours.

Heres my take on it . Your motor got really really lean...and some of us have experienced seeing some headpipes on lean 4 strokes get glowing red hot. My guess is yours was like that for an extend amount of time and that the inner wall of the tubing just melted down.