Running a 450 with a dented headpipe ?

[Polar_Bus]

Hey guys,

I took an auger this weekend on a nasty rocky uphill and low-sided right on a rock and put a decent sized dent in my headpipe. It's about 1" in dia., and I'm guessing i'm flowing about 75% ? The bike seemed to run fine, but until I can find a used replacement pipe (I got no desire to spend $340 on a new one). Should I not run the bike ? Can You possibly burn a valve and or piston when you have an exhaust restriction ?

BTW if anyone can hook me up with a clean 2007 OEM headpipe I would appreciate it ! Thanks!

[arnego2]

Hello there

if it runs fine why bother? I think that restriction is as great as you imagine.

Regards

Arnego2

[KJ790]

You're fine.

[tech24]

agreed its fine my '04 pipe has been mangled for most of its life

[grayracer513]

If you take the header off, stand it up like a letter "U", fill it with water, and stick it in the freezer, the freezing water will push most of the dent out as it expands. Do this 2-3 times and the dent will be nearly gone.

Don't melt the ice out with anything hotter than hot water, though. The titanium can get brittle when cold.

[YamaLink]

This isn't the exact "science" of an answer, but David Pearson, off-road pro and all-around good guy, smashed my headpipe with a rock during a WORCS race so bad that I could feel it in my hands (okay, slight exaggeration). BLAM-O! But the bike ran fine.

[Polar_Bus]

Thanks for the info guys, and Gray, i'll give the ice expansion trick a try, certainly makes sense. I know a lot of lazy circle track auto racers that cracked an engine block over winter from letting straight water sit in the waterways....

[jayh300]

here is mine...after 1 freeze on my wr...before

after

it is pretty much gone, i froze it one more time, but no more came out...

did it just like gray said..

[Polar_Bus]

here is mine...after 1 freeze on my wr...before

it is pretty much gone, i froze it one more time, but no more came out...

did it just like gray said..

Thanks, and yup, that's exactly where i mashed my pipe, and the exact same size mash too... LOL

[jayh300]

Thanks, and yup, that's exactly where i mashed my pipe, and the exact same size mash too... LOL

you bet.. was kinda amazed at it..

i could not tell mine ran any different, but i had some extra time on my hands (broken fibula) so it was worth a try....

[stroker101]

If you take the header off, stand it up like a letter "U", fill it with water, and stick it in the freezer, the freezing water will push most of the dent out as it expands. Do this 2-3 times and the dent will be nearly gone.

Don't melt the ice out with anything hotter than hot water, though. The titanium can get brittle when cold.

question,...does the ends of the pipe need to be plugged in order for this trick to work? or can the ends be left open?

i have a DRD header with a small dent i would like to get out.

thanks

[grayracer513]

question,...does the ends of the pipe need to be plugged in order for this trick to work?

No, in fact it's not a good idea to do that.

[stroker101]

No, in fact it's not a good idea to do that.

ok, thanks GR for the intell

[jrny426]

Done this trick myself works awesome

[stroker101]

1st attempt...frooze the headpipe(DRD Ti) once "without" end caps and all the ice expansion flowed out the ends. no affect on dent

2nd attempt...was with pipe/muffler plugs placed in both ends and the forces of the ice freezing simply pushed the plugs out. again no affect on dent

3rd attempt may be with pressure test plugs used by plumbers to cap of water/sewerage lines placed in both ends of header. need something that won't be froced out the ends so easily

hmmmmm?

Edited September 15, 2010 by stroker101

[KJ790]

1st attempt...frooze the headpipe once "without" end caps and all the ice expansion flowed out the ends. no affect on dent

2nd attempt...was with pipe/muffler plugs placed in both ends and the forces of the ice freezing simply pushed the plugs out. again no affect on dent

3rd attempt may be with pressure test plugs used by plumbers to cap of water/sewerage lines placed in both ends of header. need something that won't be froced out the ends so easily

hmmmmm?

If the pressure from expanding ice can force dents out of the pipe, it will simply push any type of plug you put in the end out (short of welding metal plugs in the ends). Don't fill the pipe up all the way, just fill it so that the water is covering a little above the dent. Stand it up in a freezer that is not disturbed much. The water will freeze at the ends first and should form a natural plug. If the pipe is disturbed much during the freezing process this natural plug can be broken loose, and the expansion of the ice simply moves the end of the ice up in the pipe instead of forcing the dent out.

[stroker101]

more info...thx. i'll try with a small amount of water as you suggested.

thx fella's for the help

[grayracer513]

It can depend a little on the "structural integrity" of the dent, too. If the form of the dent includes some sharp creases in just the wrong pattern, it can be a little more stubborn about giving up its new shape for its original.

Also, one hears this complaint when the pipe is actually stainless instead of Ti.

[Merc1212]

My experience with freezing out dings:

try 2-3 times without plugging, should work on most dents. Leave it be for 24hrs to be sure...don't disturb as KJ mentioned. If you have a major crush or a bend that won't shift from doing this, then in my experience, plugging the ends is the only way. As gray mentioned this could cause the pipe to split open, so use at your own risk. I've done it successfully 3 times to the same Ti header with no issues, although the bend did change on the last couple. I had to bend it back else it wouldn't mount up (the "U" in the pipe was wider than before).

Ok here's how you plug the ends:

1. Get a good thick piece of steel about 4" square. Drill two holes to mount the stock bolts from the engine end. Put it aside for now.

2. Use a plastic bag and some tape to seal the other end.

3. Fill that end with water, about 6-8 inches or so, to bring it past where the header has it's first bend - not the U just the kink near the kickstarter.

4. Freeze that end only. Leave it overnight with the taped end facing down in the freezer. The ice inside will be shaped like the elbow in that end of the pipe and will form a natural mechanical plug (ie it won't rely on friction, but rather it's shape).

5. Now quickly fill the remainder with water and bolt on the metal plate and a piece of innertube sandwiched in between. Put in the freezer overnight and then check every 4hrs (likely depends on freezer). If it's been more than 24hrs and no result, Take the plate off and melt the ice only in that end and refill with water and try again. 2nd time is the charm for the times I've done it. 3 times once.

I've gotten some really bad bends and dings out this way that wouldn't come out with just repeated freezing. Knowing when to quit is important too...if it looks pretty good, it's probably time to take it out. It won't be perfect, but most times all you'll see is some discoloration from where the crease was or for the bad ones some ridges.

[stroker101]

thx for all the advice and tips.

i gave up on the freezing method and went to heating the dent with my MAPP torch and push the dent out with a 5/16" rod (radius on the end)