HELP NEEDED ON THE 2003 APRILIA RS125 GP-1 REPLICA

[The Dude]

Hi folks. Someone please help me. 5 weeks ago i bought a second hand RS125 from my local Aprilia dealer. The bike was first registered in April 2003 and only had 500 miles on the clock. I had noticed it in the shop since around July or August 2003 so who ever bought it new didn't keep it very long. It is in perfect condition looks wise. My problems started around a week after i got it because during the first week it was really cold and icy in Northern Ireland so i didn't get using it at all. it has still been really cold here for the past 4 weeks. It seems that when i go out to start it in the morning to go to work, i start it as normal and let it warm up, giving it a few light revs from time to time to clear it out. It sounds really cloggy when reving it for the first few minutes after starting. But if it has been below zero degrees over night what happens is even when it's warmed up to 45°c or 50°c, all of a sudden the idling gets slow, down to around 1000rpm and then it just konks out. If overnight it hasn't been so cold, the bike still sounds cloggy for the first minute or so untill the bike reaches around 40°c and then the revs become smoother and i can ride it no problem. I have to keep the bike outside because i have know where else to keep it. I cover it at night also. I work with a lot of guys who have pretty big racing bikes and they have told me that 2 strokes are a bit more trouble to get started in the cold but once you get them started they should go no problem. My bike starts first time everytime, thats not the problem. What i'm really asking is. Am i doing something wrong or does it sound like there is a problem with the bike? I know nothing at all about bikes. At the moment the bike is back at the dealers. I have told him to keep it for a few days and use it to get back and forth to work. It certainly isn't getting me to work on time. Out of the whole time i have had it, i have probably got to work and back maybe, 10 days out of 4 weeks without problems. I would be greatful for any helpo fellas. Thanks.

[Kickstart]

Hi

Sounds a bit strange. Carb icing is possible, but I would not expect that to cause a problem while idling. The only other thing I can think of is a blocked fuel tank breather (maybe blocked with water / ice). Neither of these ideas is really that likely though.

Personally I would say start the engine and ride off as soon as the engine will safely pull. Just do not rev the engine over about 5000rpm until it is fully up to temperature.

By the way, where are you in NI?

All the best

Keith
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[M1ke]

Is it cutting out when you leave it idling? Or actually cutting out when you are riding it?

All the problem could be is the idle speed needs adjusting (little nob on side of carb).

By the way, 40-50 degrees is not warm for these bikes. You shouldn't be thrashing it until it is mid 60's on the temp. And yes they do sound rough when cold.

[The Dude]

Thanks Kick. I live in Belfast. Trouble is man, i drove of on it a few times like that and everytime i stopped at traffic lights the engine just died and even when it was going, it didn't ride very smoothly. It's really doing my head in. I need this bike to get me to work and i have been late loads because of it.

[The Dude]

The idling speed is fine Mikey. I actually have it set a little higher than it should be because when i turn my main lights on it drops by about 500rpm. So i have it set to idle at 1500rpm instead of the recommended 1250rpm. It doesn't cut out while riding. Just while stationary. I have a funny feeling who ever owned it before me has probably raked the life out of it before it's been run in. But like i said, i know nothing about bikes

[Kickstart]

Hi

I went to school in Bangor and lived in Killinchy.

Anyway you can adjust the idle speed. There is a little knob on the side of the carb. If you increase the idle speed slightly. I would set it around 1200~1500rpm, which is slightly high but far less likely to die. This should help with it konking out at traffic lights.

If you run it for too long on the choke then it will start to run badly. An old spark plug will make this worse.

Also when I first bought my RS125 the fuel filter blocked up totally before the first service. This made the bike die rapidly. However only really when you were riding it.

Sorry, without seeing the bike I am a bit stumped.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[The Dude]

Thanks Kick. Though i had a new plug put in it 2 weeks ago and the problem is still there. Anyone else out there have any ideas or had the same problem? I really need to find out soon. If it's something i'm doing wrong then i can ask my dealer to show me how to do it right. But if it's a problem with the bike then i can atleast argue with him that i either want it fixed, or the bike replaced. What i don't want to do though is go down and start arguing with the guy about it when it's me in the wrong. He's a pretty fair enough chap and has always helped me out even when i had my scooter last year. I really don't think he's trying to fob me off with a bike that has something wrong with it.

[ZaphodBeeble]

Sorry to say this dude, but if Keith doesn't know then it's unlikely that anyone else here will know. Keith is GOD. (from what I've seen anyway )
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[priller]

My rs runs like your if I forget to turn the choke off.

[ProXimaCore]

Hi 'The Dude' I've spoke to you about it before but just to let everyone else know my view. Maybe it'll spark an idea in someone...

When I got my NSR last year it was exactly like that. I could start it up but I'd need to keep the revs going myself. Even after I was driving around I'd come to a stop and if I left the revs alone it'd die. Had to keep it revving. It also usually struggled a bit aswell pulling away.

In the end my bike eventually gave in after about 500 miles of getting the bike. Needed a rebuild. Got it fixed and the problem was gone. Was running with low compression. Is this likely to be the cause of the problem for 'The Dude's' bike?
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Honda NSR125R -> Suzuki GSXR400R GK76a -> Kawasaki ZX636 B1H -> Honda CBR400RR NC29 -> Nothing

[priller]

Compression on mine was under 80 when I rebuilt it and it would normally be about 110 psi but it would still idle and run ok.

[dainesefreak]

I used to have a similar problem on one of my old RS125's. I used to keep it in the back garden under a cover and ride it all year round. It was fine until it was cold, below freezing over night. I used to start it up and ride away not long after it had started reading a decent temperature, somewhere around the mid 40c's.

I found that it was alright as long as it had a few good revs on it, but as soon as I had to slow down or stop the revs would fall straight off and the bike would cut out. It would eventually run fine when it got up to around 80c showing on the digital readout, usually about a 3rd of the way through my morning commute. I got to the point where I used to wait for the bike to warm up to near 80c before riding off.

Eventually I just started to ride the bike by slipping the clutch as I came to a stop and putting a good few revs on. The bike only ever did it through winter and was fine in the warmer months with no problems at all. I also upped the idling speed just for the colder months and put it back for the warmer months. I kept it for about four years in all and never had any other problems with it.

[priller]

Mine doesn't get to 80 at this time of year. Unless I'm stopped it doesn't go above 70.

[G]

Not sure about the problem, but if you bought this Aprilia, from an authorised Aprilia dealer, I presume it's not an import, so should still be under warranty. Even an import should come with some kind of warranty.

Therefore I'd try and get it sorted under warranty. If they only come with a one year one, then do it quick, before it runs out.

[Robby]

Sounds like its due a rebuild.

Does does it run really rough, with about a 500 rpm band somewhere that it feels ok?

Do you have any 2 stroke oil in it?

Whats the mileage?

[The Dude]

Well folks. The problem might be solved. I just got the bike back from the dealer, who took it home last night and said it was running fine. He showed me how to start it up properly. I wasn't revving it enough when i was starting it apparently. Not enough to clear the engine anyway. Also he said i wasn't riding it at high enough revs and that i was changing up the gears at too low a rev, which is true, i was. So the engine was getting choked up all the time. Basically, because it's a racing bike, it likes to be kept at pretty high revs. Does this make any sense to you guys? Or have i just been fed a pile of crap?lol

[ProXimaCore]

The only way to find out would be to go out and try it I guess. If I'm taking it easy I don't change gear till about 5000Rpm. If I'm not taking it easy then it's 11,000Rpm before I change.
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Honda NSR125R -> Suzuki GSXR400R GK76a -> Kawasaki ZX636 B1H -> Honda CBR400RR NC29 -> Nothing

[Kickstart]

Hi

It does make a bit of sense, depending on how low a revs you were running it at. I live out of town so mine gets revved to the red line regularly as soon as it is up to full temperature, except when running in. Running in does kill spark plugs so the bike no longer runs smoothly, mainly from using it at low revs too much, and using the choke too much does the same.

I tend to avoid using the choke unless I have to.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[The Dude]

What looks better? My RS or ProXimaCores' NSR?

[mr jamez]

My bike looks better, so shut it

https://home.btconnect.com/p.leigh/bike.jpg

[ZaphodBeeble]

I like the nsr more
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[bugsy46]

HI, a) why buy a bike with 500m on the clock, especially when its a 2 stroke aprilia rs125??? b) with the amount of compression in the engine and other parts, the RS125 has to be carefully bedded in. You SHOULD NOT EXCEED 6000RPM before the first 500 mile. Why are you people saying yeah give it 11 thou at 40 degrees???!!!!!

The bike aint even run in yet???!!!! And lastly, why the fuck are you trying to ride a gp replica in winter?

[True Blue]

^ ^
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Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[ProXimaCore]

[priller]