2018 Aprilia RS4 50 Euro 4 Upgrade Project

[Berkeley]

Hi Guys,

I took the bike out for a test drive yesterday and the top speed before was 96 kmh and now 100 kmh, the only thing I changed was the tyres so the MC50 must be accountable for this???



I still thinking it should be doing around the 110-115 with a 70cc BBK on it. Maybe I need to change the front socket to a 15 to help top end? Again not sure if thats just the max speed the bike naturally is or if the jolly moto 50cc exhaust is holding it back. Any ideas or thoughts would be good.
In terms of speed I would like the bike to around this mark so that it can keep up with general traffic.. On the few runs with Amaya I thought at times it was getting a bit dangerous with cars up her ass and very eager to overtake and sometimes risking it a bit too much.

Cheers Rj_666 for the link to the swing arm socket, only £20,00 inc delivery which is a bit of a bargain. For my VFR 400 I purchased one from the dealer but that was about £70.00 so glad you posted it.

GB Motorcycle Products

[kaldis12]

The Jolymoto exhaust is most likely holding it back. Im pretty sure. MC50 has less contact with the road though. Mc25 has better traction so more power needed there. You could change the front sprocket but that would change your acceleration, it would accelerate up slower.

I would change the exhaust for what can suit the metrakit cylinder. Keep in mind that the kmh counter lies about 10kmh so if its displays 110 then you are going with 100kmh most likely. When I had the same bike I had this issue. Download a GPS kmh counter onto your phone. That will display the correct number.

[Berkeley]

Cheers will do that with the phone good idea.!

yeah the acceleration is ok as it is so going to the 15 will hamper it.. not sure how much though.

I did speak to jolly moto a few months ago but they didnt get back to me . At the time they were saying I could keep the 50 tail pipe but change the rest. not sure if they had a 70cc one or were working on it hence the delay maybe.

For the price of it maybe ill look else where , I think you gave me a good reference to go to.

[kaldis12]

I wouldnt brother with the Jolymoto, they are too expensive. Maybe a Yasuni R3 would be better. Its pretty easy to fit on your bike if they didnt change the design. Yasuni r2 is good too. R3 has the powerband higher, the R2 had lower. I like the high powerbands but for easier ride you should go for the R2.

I could recommend Voca exhaust and SCR Racing Line too, but for them you need to modify the fairings if I remember correctly.

[toratora]

I’ve got two Jolly Moto pipes. One on the Silver bike, and one on the Monza (my moped). They are sweet pipes, and I don’t think the pipe is your limiting factor. What RPM are you hitting at top speed, and what are the current front and rear sprockets?

[kaldis12]

I had one Jolymoto for my bike. I wasnt too impressed with it. You can make youe own waay nicer. Other manufacturers make better pipes too. Not Yasuni, but more like 2win and 2fast. Those are some nice pipes.

[Berkeley]

Hey Guys,

Currently she is on a 14/53 sprocket and top rpm is around 11-11.5k if i recall.

I did find a nice looking Yasuni R2 Carbon Pipe that would fit



A question I have is that you can also buy some sound wadding for the tail pipe, does this affect the performance at all of just makes it a bit quieter?



On another note with the jolly moto exhaust to me most of the high pitch sound is coming from the header pipe/chamber.. this seems really tinny, I wonder if its just this pipe or are they all like this?

thanks

[kaldis12]

You can buy some wadding but they come out perfectly packed from the factory. If you put it in the incorrect amount you will end up by lower performance(not noticable, just on a dyno)/worse sound. I would buy some maybe. It needs to be repacked quiet often. I repack mine with about 4 week sequences. One repack would hold up about 1,5 month for me. But the sound changes along. As I hear the change, I repack it.

The high pitch sound comes from the chamber. Most likely all pipes like this, because of the thickness of the material what they make it out. Thats why we wear earprotection. As you go for higher and higher cc bikes that pitch is louder. At least on a strong bike. Inner rotor ignitions, what I use, makes it come out way more. Our even mini outer rotors.

[toratora]

Currently she is on a 14/53 sprocket and top rpm is around 11-11.5k if i recall.

The theoretical top speed of the bike with that gearing at those RPMs with proper sized tires is 62.870mph, which is about 101.17946kph. If you consider that wind resistance is going to be a factor, and to some extent the bike employs a "happy meter" then your results sound appropriate.

Changing the top end will not necessarily change the bike’s top speed. It may produce more power allowing a change in gearing, and it may allow the engine to spin at a higher RPM which would then effect the top speed. If you were to spin the engine at 13.5K RPM then you could expect a theoretical top speed of 73.803mph. If you also changed the front sprocket to a 15 then the theoretical top speed would change to 79.075mph. If the RPM stayed at 11.5K, but changed the front sprocket to a 15 then the theoretical top speed would be 67.360mph.

The Jolly Moto pipes are tuned for higher RPMs, so I don’t believe that the pipe is currently your limiting factor. You could ask Jolly Moto at what RPM is chamber tuned for peak power.

[jkv357]

I wouldn't expect that the Jolly Moto pipe was holding you back. It's going to be an improvement over stock, and is a performance pipe that is well respected from what I've seen.

It doesn't have restrictor plate at the inlet does it?

Your gearing sounds too low to me.