Topic: For those worried about running dented/dinged pipes or headers.

[700504]

I know I've passed up a few sets of pipes based solely for having dents and dings, not totally for cosmetics but for performance reasons as well. I'm also someone who doesn't necessarily dig the look of header wrap on honda bikes. If anything the video below is entertaining; watching Freiburger bang on a perfectly good set of headers, but nontheless interesting in the readings they got. I'm sure there's plenty of folks who like the look of header wrap, so at the very least you could have a hammered 4-1 header on your bike and never know since it'll all be wrapped up tight.

[strynboen]

no need for baying expensive headers...old #$%* tubes does the same job...are they saing that heigh..??

[DohcBikes]

Still not going to run dented headers.

[Don R]

 I'll be right back, I gotta beat the trash man to the curb.

[754]

I have seen 4-1 ground down to a D shape..  Still ran pretty strong.
....wTF Don ..they run Nightshift with the trashman..?

[Gene]

Not exactly sure why - but this pleases me to no end.

[Don R]

  The trash man comes before I want to get up Frank,
  Just kidding anyway it's riding in the back of my truck. The kind of 4-1 where at the top the outside pipes duck behind the inside pipes. The PO apparently was a curb jumper, the poor thing's beat on bad. 

[Terry in Australia]

I was admiring a set of modern Yoshimura pipes in Mick Hone's shop a few years ago, but scratching my head at the same time. I think they were for a ducati, and rather than smooth flowing bends, they had been cut and welded just about every inch and while they were beautifully TIG welded I wondered what the insides looked like, and how that would affect power? Maybe it's just not that important after all............... ?

[DohcBikes]

There are so many reasons that test doesn't show the full effect.

Lets not forget it did lose power. Just because David frieburger is sitting there saying it doesn't matter does not mean that is true.

Try that on a single cylinder engine and see what happens.

[strynboen]

or on a 2 stroke...it vill kill a smoker engine.

..but try vith a komplet muffled engine vith full back pressure..this test vith a open system  dont give any idea of a "normal " engine

[700504]

I am curious as to what happens on a smaller scale where little changes can make huge results.

Mostly, while posting this, I was thinking about the typical dent(s) on the under side of a 4-1 header that you see on old 750's.

[Duke McDukiedook]

Yeah, their test was dumb. They built in back pressure, they do realize that, right?

[700504]

This is the type of denting I'm referring to, this is the header that user turkey4me has on the 'parts for sale' page. I'd be curious to see if there is any difference between this and a pristine set with the readings on a dyno.

[DohcBikes]

Those dents arent going to make adiffernece but why not fix them with some pressure and heat

[754]

Geez when my buddies Jardine was ground flat, 1/3of the pipe was blocked.. The flat spot was over 1 inch wide..probably 1 1/4...  We ran against each other all the time, cant say it slowed that bike down....

 Look at the exhaust port, its smaller than the pipe, it gets far bigger thru the spigot...but does it need to be.?

[faux fiddy]

I have seen 4-1 ground down to a D shape..  Still ran pretty strong.
....wTF Don ..they run Nightshift with the trashman..?

You can find some good stuff at the track dumpster after crashes.  Busted plastic can be repurposed into team colored fenders for the pit bikes.

[Terry in Australia]

I was digging around in my garage last weekend and I found a NOS Moriwaki exhaust (for a Kawasaki, I think) I must see if I can "tweak" it to fit my CB750............

[mick750F]

   I believe that to repair dented wind instruments...no, not your arse...they force progressively larger balls...not yours Terry, through the instrument until it is back to the proper inside diameter. Seems like this might work with headers if you could come up with a way to work it.

[754]

I think those have a tapped hole in the, so you can pull them with a cable... And maybe a small slide hammer. They come in a set of progressivlye larger sizes, start small and each onrpe only moves the dent a bit..instead of moving the whole dent in one go..
 I have made similar things o straighten dents in  tubes in visible gas pumps .

[Terry in Australia]

Thanks Mick, my grandfather carried his cornet right through WW1 and somehow it got lost in the 1930's but ended up in a local town band in a town not too far from where my dad lived. About 10 years ago dad got a phone call from that town council asking him if he wanted his cornet back, as the band was selling off all of the older instruments to raise money for new ones?

My dad was stoked, his father had died in 1970, and it meant a lot to get his cornet back, but it was pretty beat up with lots of dents in the tubing so dad took it to an instrument repairer and when he got it back, apart from the age patina (it's at least 100 years old) it looks great, and every year on ANZAC Day (like Veteran's Day, I think?) a local guy borrows it (from my mum now, Dad died a year ago) to play "The Last Post", and swears that my Grandpop's old Cornet plays itself.

It did look a bit like those headers when it first came back to us.........

[bear]

Thanks Mick, my grandfather carried his cornet right through WW1 and somehow it got lost in the 1930's but ended up in a local town band in a town not too far from where my dad lived. About 10 years ago dad got a phone call from that town council asking him if he wanted his cornet back, as the band was selling off all of the older instruments to raise money for new ones?

My dad was stoked, his father had died in 1970, and it meant a lot to get his cornet back, but it was pretty beat up with lots of dents in the tubing so dad took it to an instrument repairer and when he got it back, apart from the age patina (it's at least 100 years old) it looks great, and every year on ANZAC Day (like Veteran's Day, I think?) a local guy borrows it (from my mum now, Dad died a year ago) to play "The Last Post", and swears that my Grandpop's old Cornet plays itself.

It did look a bit like those headers when it first came back to us.........

Nice story tez.

Regarding the headers.
Our pipes on the sidecar have 32  welds to the junction and a couple of flat spots hear and there.
There has been no decernable difference on the dyno from the original mandrel bent pipes that we could not salvage after the accident in 2011.

[mick750F]

Thanks Mick, my grandfather carried his cornet right through WW1 and somehow it got lost in the 1930's but ended up in a local town band in a town not too far from where my dad lived. About 10 years ago dad got a phone call from that town council asking him if he wanted his cornet back, as the band was selling off all of the older instruments to raise money for new ones?

My dad was stoked, his father had died in 1970, and it meant a lot to get his cornet back, but it was pretty beat up with lots of dents in the tubing so dad took it to an instrument repairer and when he got it back, apart from the age patina (it's at least 100 years old) it looks great, and every year on ANZAC Day (like Veteran's Day, I think?) a local guy borrows it (from my mum now, Dad died a year ago) to play "The Last Post", and swears that my Grandpop's old Cornet plays itself.

It did look a bit like those headers when it first came back to us.........

I love these kind of stories...makes me think of my own dad and his adventures.

[evanphi]

Thanks Mick, my grandfather carried his cornet right through WW1 and somehow it got lost in the 1930's but ended up in a local town band in a town not too far from where my dad lived. About 10 years ago dad got a phone call from that town council asking him if he wanted his cornet back, as the band was selling off all of the older instruments to raise money for new ones?

My dad was stoked, his father had died in 1970, and it meant a lot to get his cornet back, but it was pretty beat up with lots of dents in the tubing so dad took it to an instrument repairer and when he got it back, apart from the age patina (it's at least 100 years old) it looks great, and every year on ANZAC Day (like Veteran's Day, I think?) a local guy borrows it (from my mum now, Dad died a year ago) to play "The Last Post", and swears that my Grandpop's old Cornet plays itself.

It did look a bit like those headers when it first came back to us.........

That's a really great story. I just joined the army reserves to play in the band. Great players on some similarly old instruments!

[Terry in Australia]

Good on you mate, "Bandies" have a great time, they get to travel all over the world to entertain the troops, and get paid for the pleasure. In WW1, band members were also stretcher bearers, so when my grandpop wasn't playing his cornet, he was carting the dead and wounded away from the battle. Hopefully you'll never need to be in that situation. Cheers, Terry.

[evanphi]

Good on you mate, "Bandies" have a great time, they get to travel all over the world to entertain the troops, and get paid for the pleasure. In WW1, band members were also stretcher bearers, so when my grandpop wasn't playing his cornet, he was carting the dead and wounded away from the battle. Hopefully you'll never need to be in that situation. Cheers, Terry.

Yes deployment for Reservists is completely voluntary, but we are always given the opportunity. The national band is taking auditions for a 3 month stay in France for the Sommes 100 year anniversary.

[Terry in Australia]

Wow, that'd be a great gig if you could get the time off from your regular job to do it mate, I was there back in the 1970's and the rows and rows of war graves is a sombering sight. Cheers, Terry. ; D