Peashooter cracked

Nater_Potater · Sep 30, 2016

From Soni Plating's website http://sonicplatinginc.com/hydrogenEmbrittlement.asp; "All electroplating processes take place in an aqueous solution. Hydrogen gas is liberated at the cathode during various pretreatment and electroplating processes. The active hydrogen can embrittle both the chromium deposit and the steel part being plated. When hydrogen enters steel, it can cause a loss of ductility, a loss of load carrying ability and/or microscopic cracks and failures at applied stresses below the normal design strength of the steel." As I understand, it was because of the lack of understanding this principle that the early Japanese bikes had such difficulty with broken rear springs (that were chrome-plated).

They go on to say "Hydrogen can also be introduced during the fabrication and/or welding of a steel component." Combine that with the stress induced by the weld itself, and it looks like you need to have the spigots over-built a bit.

Nathan

MS850 · Sep 30, 2016

cjandme said:
MS850 said:

Duane from Commando Specialties contacted me, like always great customer PR. He's sending a new one.
Everyone I have dealt with selling Norton parts have been fantastic.

Click to expand...

Well, that's because Norton owners & riders are a fantastic bunch, don't cha know :wink:

Yes I agree, I was at the rally in Quincy, had a fantastic time, met a lot of good people and made a few friends.

concours · Oct 1, 2016

Learned something new..... how to cure the darned peashooter/kicker interference

Frankie17 · Oct 3, 2016

the inlet pipes are made from stock exhaust tubing seamed type and the muffler body is made from mild steel sheet rolled to form the cone

what makes them fragile is the fact the silencers are heat treated after welding process prior to chrome plating often making the muffler body and welds very brittle

nickguzzi · Oct 3, 2016

The system not hanging right and being forced into place can easily initiate the sort of fracture shown. The hydrogen embrittlement and or incorrect welding leading to base metal degradation in the heat affected zone are possible, perhaps even probable, but in my experience being adequately hung is the first step to a happy long term relationship.

MS850 · Nov 15, 2016

Well the muffler cracked again, new rear muffler rubbers(waisted), Im pretty sure the alignment was good, at least it looked lined up. Not sure I mentioned, new and adjusted ISO's before and after the cracking, Dave Taylor head steady.
So I took the cracked pipe to a welder and he said the welds were not sufficient, not enough penetration. I compared the welds on mine to an original peashooter and the welds on the orig look larger. Bottom line he welded it back together. Here's a few pics.
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Before crack

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After cracked

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Welded

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Orignal OEM peashooter.

gortnipper · Nov 15, 2016

Bummer. I have some new CS peashooters that I have yet to install. Hope they dont do this...

Fast Eddie · Nov 15, 2016

Lack of penetration makes sense.

As does, especially after looking at the pic of the OEM peashooter, over polishing i.e. removing too much material and therefore mechanical strength from the weld.

Which is what I said at the beginning, and I'm sticking to it !!

MS850 · Nov 15, 2016

Fast Eddie said:
Lack of penetration makes sense.

As does, especially after looking at the pic of the OEM peashooter, over polishing i.e. removing too much material and therefore mechanical strength from the weld.

Which is what I said at the beginning, and I'm sticking to it !!

Yeah you did.

MS850 · Nov 15, 2016

gortnipper said:
Bummer. I have some new CS peashooters that I have yet to install. Hope they dont do this...

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Because this happened to mine doesnt mean yours will crack, If your worried have the weld re-inforced. There was very little burn on the chrome, I buffed the weld with a wire wheel then polished with bench buffer and covered with high heat clear. Mainly so it wouldn't rust, you can hardly tell it was welded.
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gortnipper · Nov 15, 2016

MS850 said:
gortnipper said:

Bummer. I have some new CS peashooters that I have yet to install. Hope they dont do this...

Click to expand...

.
Because this happened to mine doesnt mean yours will crack, If your worried have the weld re-inforced. There was very little burn on the chrome, I buffed the weld with a wire wheel then polished with bench buffer and covered with high heat clear. Mainly so it wouldn't rust, you can hardly tell it was welded.
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Well, like I said, I hope they dont.

Looks better than all my 80s peashooters did. I had some Toga pipes on my old mk3 and my mk2 that all three of them rattled the muffler cores loose, and I had to unzip that weld to remove the broken piece of core and weld it back up. Louder, and uglier.

Fast Eddie · Nov 15, 2016

MS850 said:
gortnipper said:

Bummer. I have some new CS peashooters that I have yet to install. Hope they dont do this...

Click to expand...

.
Because this happened to mine doesnt mean yours will crack, If your worried have the weld re-inforced. There was very little burn on the chrome, I buffed the weld with a wire wheel then polished with bench buffer and covered with high heat clear. Mainly so it wouldn't rust, you can hardly tell it was welded.
.
.

Very neat...

Good idea with the clear coat, I would have used silver paint which would have stuck out like a sore thumb !!

gjr · Nov 18, 2016

The weld isn't the problem. It didn't break, it was the tube. If the mufflers are pulled up to the mounts at all, they will crack. They need to line up without any stress.

I have no idea how many miles/years I have on my broken, rewelded, heat and bent to fit mufflers with no cracking issues. Hopefully your repair fixes the problem.

Greg

MS850 · Nov 18, 2016

gjr said:
The weld isn't the problem. It didn't break, it was the tube. If the mufflers are pulled up to the mounts at all, they will crack. They need to line up without any stress.

I have no idea how many miles/years I have on my broken, rewelded, heat and bent to fit mufflers with no cracking issues. Hopefully your repair fixes the problem.

Greg

Yes the alignment is the route of the problem, fingers crossed . I dont know what kind of head pipes are on the bike, Its a MK3 with no crossover pipe and has the collet and the conical seating washer so I can wiggle around to line up the pipe with the muffler. It seems close to being square and no tension where the muffler bolts go into the bracket. Hopefully it wont crack again or Ill be making a bracket as suggested by concours.
Im sure there out the but I haven't found any head pipes with no crossover for the MK3, the left pipe really need to swing out just a little further. The pipe bumps the drain plug on the primary case if moved to far.

kerinorton · Nov 22, 2016

Hi Ian, remember I turned up to the pub at the last rally sounding like a noisy single. That was one of the original mufflers off my 750. It never broke where yours has done, but rotted through under the chrome at the join of the rear cone. Gave me a fright when it happened. Thought it had gone on on cylinder again after swallowing some carb slide.

Dereck

Peashooter cracked

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