AFR Installation - PX200

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Wed Feb 28, 2018 10:31 am

Hello,

I am planning to install a lambda sensor in order to better tune my Malossi 210 kitted PX. I have a PGM Bigbox in place and I was wondering what the ideal place to install it would be.

I thought about two seperate locations, marked with green and blue arrows here:

https://www.flickr.com/photos/150884345 ... ed-public/

Or this?

https://www.flickr.com/photos/150884345 ... ed-public/


Your suggestions are all welcome.

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Muttley McLadd
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Wed Feb 28, 2018 9:04 pm

My coop has a temp guage in a similar position to your second pic. It's fine there.. but if it was much longer, it'd be inconvenient.
Although, it does have a 90 bend in it, which makes it easier.
How much clearance would you have, if it was in the lower position?


Image
CakeAndArseParty

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coaster
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Wed Feb 28, 2018 10:27 pm

This is for an Air Fuel Ratio sensor not an EGT and I believe they need to be further away from the cylinder as the Lambda sensor is analysing the air/fuel mix rather than temperature. The one on my GTS is around 7"-8" down the pipe (the first pic would be about right) EGT's are about 4".

You won't be able to leave it fitted permanently though as the Lambda sensors don't like 2 stroke oil apparently. Having said that though, they are cheap as chips so if they last a thousand miles or so its just a maintenance item to change.....if its every 100 miles it would be a different matter.

I have a cheap digital AFR meter and will be welding a boss into my Lambretta Supertourer pipe soon for the same purpose as you.

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Thu Mar 01, 2018 9:10 am

Thanks for the information. The installation is for tuning purposes only. I will take it off and plug the hole as soon as I am done collecting the data.

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RManson
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Tue Apr 24, 2018 5:56 am

I use one on my Rotax-barrelled Lambretta. Here's a shot of the pipe before I welded the bung in that shows where I located it in relation to the header. I was very pleased with the capability and how quickly I was able to set up the carb. Good luck!

ImageRotax Lamby build-203 by PotvinV8, on Flickr

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Fri Jul 20, 2018 8:47 pm

I decided to continue this thread to share the preliminary results with you. My PX has a Malossi 210 Sport kit, that is ported. It has a BGM Big Box exhaust, KyTronik SmartBooster 2016-2, a X360 reed valve, a mechanical Dell'orto fuel pump and a Pinasco 1600g flywheel.

I decided to use my GoPro to film the AFR gauge and the SIP speedometer which I adjusted to show the rpm, but I couldn't line it up properly and ended up filming only the speedometer. I remembered to narrate some (not all unfortunately) of the readings though and here they are:

AFR Values at peak rpms
1/4 Throttle 2/4 Throttle 3/4 Throttle Full Throttle
1st Gear 11.7 11.5 10.7 11.8
2nd Gear 10.7 ? 10.7 11.8
3rd Gear ? 10.7 11.8 ?
4th Gear ? ? 12.8 12.5-12.8

I did not narrate each gear&throttle run but I seem to remember that the question marks were also around 10.5 - 10.8.

I'd imagine that I need to get a smaller idle jet and change the jet needle for a leaner mixture. I was hoping that you could give me some advise.

The configuration of the PHBH 30 carburettor is as follows with Malossi product codes:
*X3 Needle, art. B09477.003
* 262 AV atomiser, art. B09695.262
* 138 Main jet, art. B06413.138
* 55 Idle jet, art. B01486.055
* 30 Slide, art. B09374B030
* 225 Float valve, art. B09436.225 ( I changed this after installing the Dell'orto mechanical fuel pump, I can't be sure what this exact part is now. I'll check and edit this part)
* 70 Starter/Choke jet, art. B07746.070
* 9010.2 Float – 6.5 grams, art. B09010.002

I hope the post is clear, my apologies for the length, I thought I should give you all the information I have.

Thanks!
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coaster
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Fri Jul 20, 2018 9:29 pm

Watching this with interest

Colin

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Sat Jul 21, 2018 12:26 pm

I tried to line the values for the AFR/gear but it didn’t come out right in the previous post. I hope this is better:

AFR Values at peak rpms
1st Gear: “1/4 -11.7”, “2/4 - 11.5”, “3/4 - 10.7”, “Full - 11.8”
2nd Gear: “1/4 - 10.7”, “2/4 - ?,” “3/4 - 10.7”, “Full - 11.8”
3rd Gear : “1/4 - ?”, “2/4 - 10.7”, “3/4 - 11.8”, “Full - ?”
4th Gear : “1/4 - 12.5 to 12.8”, “2/4 - ?”, “3/4 - 12.8”, “Full - 12.5 to 12.8”

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joeythescooterboy
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Sun Sep 09, 2018 2:07 pm

Just fitted one on mine, what would be "ideal" values to aim for?
Nemo saltat sorbius, nisi infanus est.

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