Please Help (New Reply) Regarding Jetting!

[RalphCh97]

Hello BCF Members, I am new to bikes so please forgive me if my explanation isn't the best.
I have recently just purchased an Aprilia RX 50 Engine for my bike (Takes AM6 Engine)
I would like to run it with a Yasuni race exhaust and a ram-air air-filter.
I have a Dellorto SHA 12 14 M Carburettor.
The Jet in the carburettor is currently "63" which is stock but i need to up-jet it because of the open air filter and the Race Pipe.
I have been told to up-jet by 10%-15% if running on just the Air filter, But i am not sure how much to up-jet it by with a race pipe and the air filter. 25%?
Please can someone help me, Regarding what jets to buy (For example you can buy jet packs 80-90, Please can someone help me with what sizes to buy so i can find my idle jet.

Please respect my topic as i am very new to bikes and not to good at explaining this stuff.
Please get back to me, thanks.
Regards
Ralph.

[prawny1]

Ram air is when you feed high pressure air from the front of the bike through a duct directly into the airbox effectively supercharging the bike at speed,

It is totally different to fitting a pod/ cone type filter which I assume is what you are talking about.

Removing the airbox from a two stroke bike is going to cause you to seize up from running lean, even after re jetting the bike will be less reliable, use more fuel and be worse to ride.

The exhaust would need minor re-jetting but wont be as risky to run round with as a pod filter.

The rs/rx 50 according to the wiki is meant to have a 17.5mm carb and a 102 main jet when derestricted (74 jet when restricted).

The fact that you have a different carb will mean you will struggle with advice on jetting.

https://en.wikipedia.org/wiki/Aprilia_RX/SX_50
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[andys675]

there is no definitive answer, even 2 bikes with the same parts could be different, go as big as you can maybe even 50%, a jet too big will only knacker your spark plug, too small with knacker your engine, you need to start big and come down in size while doing plug chops (checking the spark plug colour, google it) and also getting a feel for the performance with different jets
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Some people feel the rain, others just get wet.

[Kickstart]

Hi

Presume you mean Ram Air as a make of filter.

Idle jet I would leave for now. Main jet is the important one. Do as andys675 says and start big and work down. Remember to move the clip on the needle as well (closer to the pointy end to richen the mixture).

All the best

Keith
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[_Iain_]

[RalphCh97]

The only reason i am running it on a open filter is because the CPI air box (I have CPI) is different to the air box on the RX, the manifold is bigger, So i am having to run it on a pod filter.
This is the exhaust i have:
https://www.pedparts.co.uk/c/products/RAW/Yasuni_Cross_Exhaust_System_-_Derbi_Senda.jpg
This is the Pod filter i have: Its huge:
https://www.adrenalin-pedstop.co.uk/upload/359x359/09978-MR-016.JPG.jpg
And thanks about the information, I have just posted this to see if anyone has any more information, If so please reply.

[_Iain_]

Go 120 and plug chop it.
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Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[RalphCh97]

Hello would you be able to explain what plug chopping is :) sorry about this, new to bikes!

[A100man]

[RalphCh97]

Thanks very much everyone, You have really helped me, Ill see you around the forums.
Regards
Ralph

[_Iain_]

https://hondaspree.net/wiki/index.php5?title=Spark_Plugs_and_Plug_Chops

Have a read mate, run it slightly rich if anything. Also when fitting the new motor make sure to bleed the two stroke pump. Set the throttle cable up, then make sure you time the autolube pump up right - Oiling too much/too little will muck the jetting up too. Be wary of air leaks too & be sure to oil the pod filter up as again this can also affect the jetting.

I'm sure you'll figure it out!
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[RalphCh97]

Thanks very much for your help, I will do, Thanks again.