Villopotos yz125 PC pipe Question

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6/1/2019 6:58 PM

Anyone know the story behind the pipe in this pic? More recent race pics look like the standard pipe---but I was wondering if the one below was just for show, or modded for go. Off topic, I recall Pastrana running a chopped up bare FMF at steel city when he was racing out of a box van at a national many moons ago--- heck, it may have been an amature day on the pro weekend due to his age... it was that long ago. I asked him about it a few years but he didnt know much about it. I still long to find the pic I snapped of it.... but his was modded closer to the silencer. Anyway, and ideas on Ryans pipe?

http://gatedrop.com/villopotos-yz125-ready-for-racing/

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6/1/2019 7:19 PM
Edited Date/Time: 6/1/2019 7:35 PM

Custom pipe.

Photo

PC off the shelf for comparison.

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Photo

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"Sorry Goose, but it's time to buzz the tower."

6/1/2019 7:31 PM

Almost looks like they cut up a production PC rack pipe and put a PC KTM mid section and welded it all together. Kind of a "Franken-pipe". I'm purely speculating but that mid section looks really familiar.

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6/1/2019 10:04 PM

Looks cool, ehh? Different rear shock, and obviously some other changes- cluch, brake, etc

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6/2/2019 1:13 AM

I'd say for more top end at the sacrifice of lower power. Something us mere mortals couldn't keep up in the curve enough to take advantage of.

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6/2/2019 3:35 AM

No S/N Photo

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6/2/2019 5:38 AM
Edited Date/Time: 6/2/2019 6:35 PM

Looks very similar to the 2019 KTM 125 pipe design. Before 2019, the 125 pipe looked like all other 2 stroke pipes, a fat expansion chamber. If one were to review the 2018 KTM 85, it will show the pipe takes on a similar shape. KTM improved the exhaust ports for better port timing on the 85. The exhaust port change warranted the pipe shape change. This design change in ports/pipes carried over to the 125 in 2019.

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"Hope is not a strategy"

6/2/2019 6:24 AM

He said mitch built him a special pipe

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6/3/2019 10:34 AM

They did 200+ dyno runs on that bike and tailored it to a preference Ryan was asking for. The pipe has a lot more bottom to mid with that motors particular porting and ignition setup. That pipe pictured will not rev out on a production setup. The production pipe offers more performance for a production setup.

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6/3/2019 2:43 PM

when you build performance two strokes you GENERALLY end up wiht higher ex durations. In the case of the YZ this is generally true
In doing so - a pipe designed around production ex duration is GENERALLY too short.
A little length in the right place goes a LONG way. My Instagram feed shows a modified HGS we used to do for ktm85 and 105.
It was worth almost 3 hp vs std HGS pipe - with better curve. However that pipe would LOOSE power on a stock engine...

Pipes are built for the engine combo - and everything has to work together. This applies to ignition curve as well

A truly really highly tuned 2 stroke requires all of these to work with each other, especially now days.

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6/3/2019 3:01 PM

Looks like they added about 10mm length to the midsection....

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6/3/2019 3:51 PM

It’s the PC Yamaha 150 pipe

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6/3/2019 4:10 PM

Derek Harris wrote:

when you build performance two strokes you GENERALLY end up wiht higher ex durations. In the case of the YZ this is generally true
In doing so - a pipe designed around production ex duration is GENERALLY too short.
A little length in the right place goes a LONG way. My Instagram feed shows a modified HGS we used to do for ktm85 and 105.
It was worth almost 3 hp vs std HGS pipe - with better curve. However that pipe would LOOSE power on a stock engine...

Pipes are built for the engine combo - and everything has to work together. This applies to ignition curve as well

A truly really highly tuned 2 stroke requires all of these to work with each other, especially now days.

I reckon you could build s stronger motor for him!
What simulator do you use btw?

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6/3/2019 4:43 PM

Looks like it's a smaller diameter from the I.D. plate back.

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6/3/2019 5:41 PM

I heard they also swapped the pull rods for a little extra torque.

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