2018 Aprilia RS4 50 Euro 4 Upgrade Project

[Berkeley]

The JM dealer got back to me today, They can supply a 70cc exhaust for 310.00 euros exc. postage. The silencer is the same for the 50cc, so I dont need to buy it. He thinks there can be a 2k rpm gain on it.. Still very pricey for an exhaust. I'm considering either selling the current one and getting another or testing this one out ( if no one has) to see how it performs.


I did find an SCR one for 256.70 on Dam Sport and saw on other sites that part of the belly pan fairing has to be cut away.


The Yasuni R2 comes in at 258.20 on la-becanerie.com


The 2fast is again on the expensive side at 409.99 and looks very basic. scooter attack


And I think finally the Voca for 346.00 at Scooter Zone, this looks good but again unsure how much modifying the bike will need to fit it.

[kaldis12]

From what you posted, the most advanced exhaust is the 2fast. Thats the best for sure.
My list would be this.:
1. 2fast( for you it would be unnecesarry)
2. Voca (better for bigger setups too)
3. Yasuni ( good for this setup but for biggers its not)
4. SCR( because you have to modify some things there)

Hope this helps a bit.

[jkv357]

Did they give you any dimensions for the "new" pipe so you could compare it to what you have?

How high did it rev with the stock pipe? Do you have tube dimensions for that?

Still seems odd that the JM pipe would be holding you back, but maybe it is.

[kaldis12]

If you look at the numbers the 50cc JM pipe stops working around 11.5-12k rpm. Cylinder could rev more witb this exhaust too but it has no power for it. And it wouldnt have power over that point. Bike stops around 11-11.5k so thats kinda real.

Anyway yeah I would be kinda interested in the new dimensions. Exhaust range should be like from 9,5k to 13.5k or 10-14k. These should be good. Propably the 9.5k would be better for this setup.

[Berkeley]

Hey guys , I did ask for some measurements but refused to give them to me.. the Orginial stock exhaust was reaching 7k-9k absolute max.. but this was on the 50cc head

thanks

[kaldis12]

For the stock thats ABOUT real. Not really but close.

If they dont give it to you then forget the JM pipe. Dont buy it as long as you dont know what are you buying.

[Berkeley]

Hey Tora, doing some more research here .. What model of Ohlins did you manage to fit and did you do any mods to it? or just fitted it and see how the bike performed?

After extensive searching I came across this company who actually published some data on the shocks on their website.. unlike Ohlins themselves.

To me a close match is the one for the Ninja 400R, the KA041 which has a length of 284mm and stroke of 41mm.




I've spoken to 2 different suspension companies and none have mentioned this one before .. I wonder why Also on the ones they have suggested , which I recall having a stroke of around 70 they were scratching their heads and seeing how it could be modified without making it ridiculously expensive?

anyway just putting it out there.

Cheers

[Berkeley]

https://youtu.be/kVkrnVkffdU

I remember seeing quite a knowledgeable guy called James at JHS Racing taking apart an Ohlins Shock for a YouTube program called 44 Teeth.

So after speaking to him today he will build a complete custom shock for the bike as modifying one from another bike is a bit of a half arsed job and would be difficult to match up exactly. I asked if he could document it so I could share it on here.................... so lets see.

[kaldis12]

Bit if an unabashed question(hope its the right word for it), but how much does this cost? Im looking forward to buying a new one for me too.

[Berkeley]

Bit if an unabashed question(hope its the right word for it), but how much does this cost? Im looking forward to buying a new one for me too.

No..Not at all, good we share info on cost too as it helps makes a decision!!!

Great question btw... Ill tell you when hes finished with it He's given me a max price of £1200.00 but thinks it will be under that... Giving me the higher side of things so I'm not shocked later.. excuse the pun

He can also supply the front forks too..

If you do want some then let me know .. maybe theres some discount in it