Author Topic: Taking the piss  (Read 12261 times)

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Offline FourstrokeForever

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Re: Taking the piss
« Reply #30 on: November 11, 2013, 09:07:56 am »
Corrosion works inward from the surface - the damage to this piston is on its surface.
I'm not sure what people think is going to be the problem?

The problem is obvious.....  Apart from the piston being CRAP and having dodgey looking ring lands, You have to ask how far the corrosion has gone  ::) Add Fuel, a big spark and BOOOM, there goes the answer!
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Offline NSR

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Re: Taking the piss
« Reply #31 on: November 11, 2013, 08:04:25 pm »
It is a nos SWM, Elko piston.
This is a 2nd OS piston I will first be trying to find replacement for the 1st OS thats in the bike now.  When the time comes, If I can't find another, I will look at getting it coated.
Thanks
   
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Offline FourstrokeForever

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Re: Taking the piss
« Reply #32 on: November 12, 2013, 08:09:51 am »
You can get a piston made from forged billet for around $300. A mate of mine who modifies just about everything with a combustion chamber gets his pistons made and has never had a problem. If you need a contact number, let me know.
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Offline shelpi

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Re: Taking the piss
« Reply #33 on: November 14, 2013, 12:41:44 pm »
You can get a piston made from forged billet for around $300. A mate of mine who modifies just about everything with a combustion chamber gets his pistons made and has never had a problem. If you need a contact number, let me know.
I would like the details if thats ok ;)

Simo63

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Re: Taking the piss
« Reply #34 on: November 14, 2013, 01:14:55 pm »
You can get a piston made from forged billet for around $300. A mate of mine who modifies just about everything with a combustion chamber gets his pistons made and has never had a problem. If you need a contact number, let me know.
I would like the details if thats ok ;)

Try these guys Shelpi, they are right next door tomy mates factory and make pistons for just about every single combustion engine known to man:

http://www.specialpistonservices.com/

Cheers
Simo

Offline shelpi

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Re: Taking the piss
« Reply #35 on: November 14, 2013, 01:22:45 pm »
You can get a piston made from forged billet for around $300. A mate of mine who modifies just about everything with a combustion chamber gets his pistons made and has never had a problem. If you need a contact number, let me know.
I would like the details if thats ok ;)

Try these guys Shelpi, they are right next door tomy mates factory and make pistons for just about every single combustion engine known to man:

http://www.specialpistonservices.com/

Cheers
Simo
thanks Simo  ;) do they make 1 stroke pistons :o

Simo63

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Re: Taking the piss
« Reply #36 on: November 14, 2013, 01:27:45 pm »
thanks Simo  ;) do they make 1 stroke pistons :o

Haha cunny funt  ;D

Offline shelpi

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Re: Taking the piss
« Reply #37 on: November 14, 2013, 01:49:39 pm »

Offline TooFastTim

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Re: Taking the piss
« Reply #38 on: November 14, 2013, 01:55:31 pm »

Offline EML

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Re: Taking the piss
« Reply #39 on: November 14, 2013, 03:40:58 pm »
Try these guys Shelpi, they are right next door tomy mates factory and make pistons for just about every single combustion engine known to man:

http://www.specialpistonservices.com/

Don't foreget to tell 'em how hard you rev it tho....... ;D :P :o

Offline Nathan S

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Re: Taking the piss
« Reply #40 on: November 14, 2013, 06:10:10 pm »


The photo doesn't show it clearly, but the piston that's front and centre has some 'lovely' marks from some vice jaws. It has also been dropped, more than once. It was in my YZ125D when I first bought it - it was rattly as hell, and the lack of compression meant that the only way to make the bike go was to rev the hell out of it. Went alright once you gave it a big rev...
Bultaco Macca's ribbing finally convinced me to give it a freshen up after a couple of meetings, but it never blew up.

The piston on the left was from my DT175 racer. The bodgy air cleaner fell off during practice at Canberra. I didn't realise that this had happened until it stopped... After removing the spark plug, I discovered a small oblong shaped rock stuck between the spark plug electrodes. Put a new plug in (thanks Den!) and it went fine. Did three more meetings like that, including one at Clarence where the thing was pinned in top gear, trying (dismally) to clear the big table-top in the middle. Then I pulled it down to discover that my little oblong rock didn't begin life as an oblong - my poor little DT175 top end had made it into one...

The piston on the right of the photo came from my MX250. The "sponsored rider" (we'll call him Marty to protect the innocent - and incriminate the guilty) forgot the golden rule of "change up when the power flattens off" and tried to find more power by revving it harder... The poor old DT piston and its poor old dykes ring didn't like 20,000rpm and the top ring exploded. This one actually stopped - but only because the bits of broken ring ended up in the main bearings... There was no piston drama.



I managed to not get a decent photo of it, but the 4th piston is a DT175 piston with the holes very roughly enlarged to something like IT175 spec. It came in an IT175 I bought - I can't vouch for how many hours its done, but it clearly isn't new. Again, no sign of dramas because of the shitty piston.

Maybe the moral of this story is that Yamahas are built better than Rotaxes, but I doubt it. I think the real moral is that I shouldn't let Marty ride my bike... The secondary moral is that some corrosion on the surface of a piston isn't going to worry it.

A good mate had a motor built for his rally car (Datto 180B). Proper motor it is too - it makes about 20kW at the wheels more than anyone thought was possible a few years ago. The engine builder is a talented dude who has a reputation for being a bit rough - this roughness resulted in my mate's new motor killing a head gasket before it had been run in.
My mate pulled the head off, to discover that one piston had multiple (incorrect) valve reliefs cut in it. He was almost hysterical, but was eventually convinced to put the bloody thing back together with the 'bodgy' piston. It made the power it was supposed to, and has given absolutely no grief to date.



« Last Edit: November 14, 2013, 06:13:09 pm by Nathan S »
The good thing about telling the truth is that you don't have to remember what you said.

oldfart

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Re: Taking the piss
« Reply #41 on: November 14, 2013, 06:30:28 pm »
Nathan ....you are a cruel cruel man ..... with regards to LHS side piston, you didn't pull the head off to see what was going after the ride  ::)
The combustion area would have looked similar.... also you should of noticed  it lacking way in power at the least.   

Offline Nathan S

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Re: Taking the piss
« Reply #42 on: November 14, 2013, 06:52:04 pm »
2nd ring was happily holding compression - power loss was minimal.

Yes, the head was just as awful. I knew it wasn't right, but I had about 400 DT175 motors at the time (and no time to f$%k with bikes) so it made more sense to keep running it.
The good thing about telling the truth is that you don't have to remember what you said.

Offline Davey Crocket

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Re: Taking the piss
« Reply #43 on: November 14, 2013, 09:10:43 pm »
Hey Nathan, I used my Monaro the other night to take a friends daughter to her graduation in the city, it was a long que to drop them off at the door and there was a lot of cool old cars...the mum and dad cars where suppose to park up and let the by now all overheating dinosours drop the kids at the door...low and behold what goes past the other way after dropping some poor embarrassed kid off...a farken Volvo.....I thought of you straight away and thought...gee that's a long way to come....Yass to Brisbane.....you wouldn't do that to your daughter would you?....in amonst GT Falcons, Mustangs, Camaro's, all sorts of convertables....even James Bond was there with a Aston Martin. ;D
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Offline Nathan S

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Re: Taking the piss
« Reply #44 on: November 14, 2013, 09:22:31 pm »
Peter Brock and Jim Richards disagree with you.
The good thing about telling the truth is that you don't have to remember what you said.