Removing dents from expansion chamber

[Micahdogg]

So the good news is I finally got my bud to pull the trigger on his first bike.................and it is a....................................drumroll.
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CR125!!!!!!!!

No thumpers around here.

The bad news is he had virtually no money and had to buy a beater for $850.  This is what he got:


Since it needs some tires, linkage bearings, sprockets, etc.... it would sure be nice to salvage this pipe.  I've tried filling pipes with water and freezing them, but quickly found out that they can over-expand and not only remove the dent, but split a seam in the process.

Has anyone personally tried compressed air and heat?

[PhilR]

I have and it works pretty good.I'm sure there are people out there who are quite expert at removing those dents..
I found it worked best with about 40psi ,but you have to use moderate heat..dont get the metal red hot,it can blow a hole right through.
Phil

[Micahdogg]

Thanks for the reply.  Did you notice it discoloring the nickle finish at all?

[ACMX]

Thats a good deal he got there. That pipe should be fine for a beginner rider. Won't affect him much. He's going to beat it up anyways. But if you need to repair it, the three options I know of is freezing it like you said (if you do some math you should be able to fill it to the perfect amount) or you can use heat and compressed air, or send it to a pipe repair company.

[TotalNZ]

Thanks for the reply.  Did you notice it discoloring the nickle finish at all?

Yeah you get discouloration but you can get rid of it with 3m pad on a drill or grinder.
Like PhilR say's around 40 psi and not to hot, i've gone to 60psi with no problems. to regulate pressure properly you need to have a controlled leak. lots of ways you can do it.

[MCGRIDDLE_321]

the guy that builds my race motors does like 20 psi maybe a lil more and gets it red hot. turns out perfect... but im not positive on what psi but ive watched him do it.

ps.... my pipe is a works, so im not sure its different if it is chrome or a raw finish

[TotalNZ]

the guy that builds my race motors does like 20 psi maybe a lil more and gets it red hot. turns out perfect... but im not positive on what psi but ive watched him do it.

ps.... my pipe is a works, so im not sure its different if it is chrome or a raw finish

the aftermarket pipes are thinner and you need less pressure.
I'd say your nickel finish would be history after you've had a blowtorch on it.

[Watson777]

www.piperepair.com...... Tell them Devin sent ya

[Howorks]

+1
They do great work.

www.piperepair.com...... Tell them Devin sent ya

[MyckMcClung]

Honestly, I'd put my money where it counts on this project, linkage bearings, chain& sprocket, brake pads&fluid, tires, and basic maitinance. that pipe, from this side anyway, is fine as/is for the time being. Now if the headpipe section before the expansion chamber, the skinny part coming out of the exhaust port that curves left then down then right before it gets fat, is bashed to shit, and I mean smashed, not a couple little dents, repair it, that is where you will loose the most performance.

[Micahdogg]

Thanks all.  I think it probably is best to leave it alone until he gets some riding experience.  The head pipe is dented up pretty badly, but not bashed.  The goal was to just make it look better.

[MyckMcClung]

Looks schmooks, if he wants something pretty tell him to find a girlfriend, she, hopefully won't recieve the amount of abuse this bike will get.

[Micahdogg]

Hey man, looking good is half the battle   I like show AND go.

[MyckMcClung]

Hey man, looking good is half the battle   I like show AND go.

Me too. Now that I crash with less frequency.

[snook620]

Thats a good deal he got there. That pipe should be fine for a beginner rider. Won't affect him much. He's going to beat it up anyways.

Agreed. Unless its smashed I would worry about those little dents now, your just going to crash and beat it up again anyway.