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Just because we get a few pepole who have just got an RS and dont know what the bike is about, and those who are unsure or getting one because they think its "unreliable" etc...

Purchasing an RS125.

Well what are you looking for?

When buying an RS125 you have to be aware of the following:
They are not unreliable bikes, forget all the myths you have heard, even with all the posts on this forum with broken bikes that?s what a lot of people come on here for, forget all that rubbish. These are solid bikes. They are one of the most highly tuned road bikes, the Yamaha R1 produces 150 hp per litre (engine capacity), while your RS125 produces a massive 250 hp per litre.

I will not mention how to derestrict your bike in this topic, just how to look for a good RS and identify factors in the bike those aren?t problems!

Firstly when you?re looking at a bike, check it?s mileage like any bike. Be aware in the RS125 manual, it suggests you check your piston rings at 9,000km and change the piston and rings at 16,000km. So if it?s past these mileages ensure that this has been done by the previous owner. It?s not a vital thing, but if it?s past 16,000km you should change piston and rings and a lot of experienced RS owners would do so. There are arguments and evidence that they last for over 30,000km, some still going from when they were made but I wouldn?t take the chance.
Its cheaper to change a few rings and a piston then changing the barrel, possibly bottom end parts e.g. con rod if it seizes which two strokes are known for doing.
Plus you?ll ensure that you bike stays on the road and your getting the best performance.

You will know a good RS when you see one. It will have been looked after properly. E.g. chain and sprockets are in decent condition, just the general condition of the bike. Self explanatory really.

You should also note, you should definitely use the best and nothing but the best 2 stroke oil in your RS. Something like Castrol TTS, which is typically ?11 a bottle (1 litre). Expensive yes, but cheap compared to stripping you engine and replacing main bearings etc due to using poor 2 stroke oil.

Top end rebuilds are common as I have mentioned, e.g. every 16,000km change your piston and rings. Therefore you must be handy with tools, if not get your local bike shop to do it but again remember this can be expensive. Its not a hard job really and you?ll learn a lot about your bike if your handy with tools.

If you are purchasing a full power bike it will have a power valve in it. This is a mechanism that makes the exhaust outlet wider and narrower as the revs increase and decrease giving the best performance. The blade that moves in the barrel (cylinder) can sometimes get stuck. You should remove the power valve blade regularly and clean it to ensure it does not get stuck.

The older bikes e.g. 1998 were the most powerful bikes manufactured As the years have gone by more restrictions have been put on this bike to pass emissions tests. If your testing a RS125 and you notice a terrible splutter around the 6000rpm mark this is the first restriction. This is a CDI restriction, which retards the ignition when at this rpm. This can easily be removed so it is not a problem with the bike.

Another factor which restricts the bike is some have a CAT in the exhaust. This can be removed by splitting open the expansion chamber and removing it then welding it back together or purchasing an expansion chamber without one in. This can either be after market expansion chambers e.g. Arrow, JL or just a standard Aprilia one from a different year.

If the bike doesn?t get a significant power increase around 8000rpm then this bike is learn legal at 17 with a cbt. The bike can be fully derestricted to a claimed 33bhp by installing a power vale that I mentioned earlier.

The earlier bikes had a 34mm carb on them, but they were replaced with 28mm carbs. This means the newer bikes do not get as much mid range power. So if your test riding different years beware of this. You can always get hold of a 34mm carb and manifold inlet and put this straight on to the bike without any extra parts to get that performance.

Mods. If you get to an RS and its not standard make sure its been set up correctly. If you notice its got a fancy air filter on there make sure it has been jetted accordingly by the owner. If not the bike could be running lean! This is very bad, meaning a seizure is very likely when a bike is running lean. If you notice a different exhaust and expansion chamber, make sure it has been jetted. As if it originally had a standard expansion chamber with a CAT in it, it will be running far too rich. Not a bad things, just the bike wont run as well and the carb will have to be rejetted.

You may hear in a lot of adverts that the bike has had a full engine rebuild just recently. When I first got into the RS125 I was wondering why. Why did people rebuild their bikes even if it didn?t seize! It made me very suspicious of the advertiser. However, as I mentioned before, these bikes do need to be rebuild after so many miles. If its had a full engine rebuild recently and you know the work is good e.g. receipts to prove the work or the owner sounds like a convincing D.I.Y person then it?s a positive really. However, make sure they have used decent parts. You can get pistons for ?18, however I wouldn?t stick this in a lawn mower. Make sure they have used genuine Aprilia parts or decent aftermarket ones e.g. Mitaka. They are bikes off the track, just look at a formula one car, they last for 2hours or 200miles and the engine has done its job. The RS125 is similar, its so highly tuned from standard it needs rebuilds more then normal road engines because its a race bike!

Ensure the owner has treated the bike well. If you go on a test run and the bike feels cluttered maybe they aren?t a confident rider, just give the bike a good blast and it will soon clear up.

That?s about it really. Just because they owner is a boy racer doesn?t mean the bike is thrashed. As long as its clean, and you have looked around the bike well and noted my points you should have no problems. If maintenance has been followed you should get yourself a nice bike. You may want to have a quick look in the manual and see the type of work that has to be done. It may sound like loads now, but its honestly not much. Adjust the chain here and there, clean the power valve now and again, top end rebuild after 16,000km and full engine rebuilds every so many years really.

These are very very fun bikes! Once your on them you?ll love them. It?s a 125 enjoy it, throw it around the corners, remember the RS was voted the 2nd best handling bike made! Hope you get a good one!
 

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Destroyer of the innocent
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this thread needs a sticky!

nice one burntime
makes me consider a 125 myself!
 

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well done bril read
 

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Grr Im always saying 26mm carb lol, changed it sorry.

Thanks for the comments guys, just I bet we get people on here looking to buy an RS then turn away because of all the myths, and maybe they test ride them and they are restricted and think they are rubbish!



Torpedo u on a 125 lol! Id like to see that
 

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Destroyer of the innocent
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Torpedo u on a 125 lol! Id like to see that
maybe you will rofl


that or a 600, havent decided. but lets not have that discussion here lol. So how do you set up a carb and know if its running lean or rich anyway?
 

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rejet and plug chops
 

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rejet and plug chops
Yeah, chocolate 'mocha' brown plug end should mean its running pretty sweet

Best was to do a plug chop is go along a empty dual carridgeway or similar, go about 10000rpm in top gear, hold it there for about 10-15 secs, then hit the kill switch, pull the clutch in to disengage the drive, and stop in a layby and whip the plug off and inspect

For a spark plug reading guide, to check how your bike is running i.e too lean, too rich etc, google it
 

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Happy to help. Also stops you buying a rat bike and then getting people complaining they are rubbish.

Let us know if you get one and get some pics of it up so people can see it.
Burnttime's the man


Followed your advice to a t and got this immac RS125


Thanks a lot buddy, here's the spec:- immac con, 17100 km on the clock, full service history,MOT and all the engine work approved, 1 lady owner all for ?1250 cant stop smiling


Heres the pix:

http://i103.photobucket.com/albums/m130/ke...ApriliaFrnt.jpg

http://i103.photobucket.com/albums/m130/keokai/ApriliaRt.jpg

http://i103.photobucket.com/albums/m130/ke...iliaLftside.jpg

YEH


THANKS MAN
 

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Glad to hear someone happy.

Thats a nice bike that, very immaculate. What year is it? Also, whats the wire coming out from under the tank? Just intrested.

Glad you got a good buy, hope you keep it that way

Nice colour scheme as well, I was going to do my bike in that but ended up going for the tiger.
If you have any problems just give us a shout and i'll do my best, but hope it stays mint
 

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Glad to hear someone happy.

Thats a nice bike that, very immaculate. What year is it? Also, whats the wire coming out from under the tank? Just intrested.
looks like temperature probe possibly?
 
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