RS50

[Sacarius]

A friend of mine has an rs50, he would like to know if there is any way of derestricting it. It will currently do 45mph and gains nothing by going up into 5th gear.
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[rsooty]

If he wants it to go faster put it on a trailer, attatch the trailer to a car... And drive the car works a treat!

Sooty

[Ste]

If it does 45mph then it is at least partially derestricted as it will be limited to 30mph to start with.

Try asking on www.sc-ooter.com as they probably know more about RS50's then here.

[Keith]

If its doing a top of 45mph, it IS de-restricted. Is it one of the newer models?
If it is a newer model, it has a smaller exhaust port to restrict them even more.

You can take the exhaust off and check for a cone in the head of the pipe, but its probably been removed if your getting to 45mph.

Your mate will have to put up with 45mph top speed i'm afraid, unless he wants to spend a good £300 on a big bore cylinder and performance exhaust
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Aprilia RSV Mille R Edwards Replica - Aprilia RS250 - Suzuki GSXR600 Supersport Race Bike

[Kickstart]

Hi

It should do more than that (although maybe not if it is a very late model one). The exhaust is restricted with a cone in the down pipe. Some people just cut the cone down to gain a bit more power but still not make it full power, so it might be worth checking the job has been done properly.

All the best

Keith
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[yambabe]

From my other half, who is an aprillia-certified mechanic & works in a scooter shop;

The cone in the exhaust has to be competely removed & the carb needs a 75 jet.

This will then enable it to redline in top gear (on the flat!). If you've got 12000rpm, you should get about 55 out of it, depending on the weight of the rider.

Also, may seem obvious but make sure the tyres are pumped up to max recommended pressures (30 rear, 27 front).

If this is still not good enough, have a look at chiselspeed or malossi websites (do a google) for advice on big-bore kits, then make sure you are sitting down when you look at the price of the bits.....!
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[stinkwheel]

It is probably CAPABLE of doing more then 45mph. My 1971 honda C50 will do that.

What it WILL do is wear out very quickly if you attempt to tune it further. Not familiar with that particular bike but I assume it has nikosil barrels, check out how much these things cost to rebore before undertaking any high revving 50cc antics.

Take it from me that 2-stroke tuning is a black art. Any of the following may liberate more power if properly applied:
High flow air filter.
Double cone spanny exhaust.
Remapped and advanced ignition.
expanding or closing down the ports.
Racing reed valves.
Gasflowing ports.
Skimming head.
Water injection.
Reprofiling throttle valve.
Fitting race spec conrod and piston.
Running it on methanol and castor.
Selecting correct carb choke diameter according to extent of above work.
Fitting a non o-ring chain and keeping it spotlessly clean and lubed with EP90 engine oil.

If you do all of the above there is every chance it will do 80mph plus. 200 miles later it will need stripping to the crank and rebuilding...just like the racers do.

I would recommend doing only the last point thereby minimalising the depreciation on the bike so your mate can flog it and buy a bigger one when they are allowed. High performance 2-strokes are toys, they break easily. If you have a lot of money and don't rely on the bike for transport then send it to a reputable 2-stroke tuning company like Stan Stevens with a blank cheque and have fun at grin factor 10

Ex-owner of an RD350 (well 375) powervalve with all the above done to it (except the water and methanol). Stuffed pretty much anything on the road up to 80 on the back wheel, cost more money than you would believe to keep on the road. I paid a professional to do that stuff by the way and it was borderline unrideable at road legal speeds! Returned 20mpg tops, drank 15 quid per liter synthetic 2-stroke at a rate of knots and barrels at a pair per 5k miles
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[Frost]

the RS50, and Rx50 and all 50 aprilias all use the same engine. 45mph is a realisitic derestricted maximum speed.

It can be made to go fast but by tuning rather than derestricting.

Bore it out, etc will make it go faster but for the money it will cost buying a 125 is probably the cheaper and simpler alternative

[carnislick]

hmm, well my Derbi GPR 50 will pull around the 60mph mark (give or take a few mph depending on conditions etc), it is a 2001 model so it did escape the catalytic converter but models i think after 2003 will have them.
If he has a newish model then it will have the smaller exhaust port and the cat converter.
This can be over-ridden by buying an aftermarket 50cc cylinder and piston set (Metrakit sell them) and an aftermarket exhaust. These two items should see his bike pulling a realistic 60mph maybe a bit more if he buys slightly higher spec parts and not just the cheapest he can find.

However if it is an older model then can i suggest new piston rings as it may just be very down on compression.

Paul
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Paul

[stinkwheel]

[Kickstart]