Aprilia RS25 - High pitch noise

11 posts / 0 new
Last post
Aprilia RS25 - High pitch noise

Hi, I've been having some issues with my aprilia this past week, so for the past week I've been getting a bus (Waa, I hate the bloody things...) well, I decided to start my bike up today to see how it was doing, but something weird happened... The problems sort of stopped. The bike isn't revving it's self and isn't cutting out while warming up, thus I decided to take it for a ride.

 While riding it I couldn't go above 5.5k in gear 5 and 6, (I got it to 50MPH though) and it was making a REALLY high pitch noise, more like a squeal.

 Any ideas why this is happening?


Hmmmm.... does it make the same noise as the same revs in neutral if you rev it?

If it's a very quiet noise then it might just be a blocked petrol tank breather - that could restrict fuel flow and stop it going very fast. It would also make it run very lean which is a BAAAD thing for a two-stroke.Louder squealing noises can be caused by air getting out of the cylinder heads - through a lose spark plug, dodgy head gasket or a cracked head. Squealing can also happen if the clutch is misbehaving, or a something is binding or a small, high speed bearing is failing. In a 2-stroke something binding could be the piston trying to sieze, though I suspect if it was that close it'd just sieze & we'd be having a different discussion! Does the squealing vary in pitch or volume depending on what the bike's doing? e.g. with engine revs, with road speed, with throttle position etc?You suggest that the bike had a previous problem that has now stopped? What were the symptoms of that? "revving itself" and "cutting out at idle" sound like fuelling problems to me.

Well, last wednesday, apprently the "wind" blew my bike over when I was at college, but I reckon someone knocked it. After that date it hasn't been running correctly; --Didn't happen today, but has happened--

  • Starting up, but not ticking over (Not unless I give it around 500RPM+)
  • Revving on it's own (Stopped when I switched the engine off)
  • Cutting out while riding (Only happened once)
  • Horrible engine noises (Can't really explain, but it was having issues with performance, first gear - had it take it to around 6k before I could go into second
  • Past gear 3 engine noises stopped

--Squealing Noise-- The sqealing noise happens over 5k revs past gear four (I think). I had the throttle pulled as far as it could do, it was having massive issues getting to 6k revs. The noise was loud enough to hear it over the wind with all my gear on.Now that I think about it, I reckon i've had a fuel blockage, or something along those lines (Don't really know anything mechanical, but my dad does - he hasn't been able to help due to work, over seas all week)  To answer the admin, no squealing noise in N when I rev it.  I love my little bike, before I go anywhere I let her warm up to 45degrees celcius, when I bought the bike (It apparently had a new engine build)  I never took her over 5.5k for around 8 weeks (I do 20 miles a day on her, around 4/5 times a week)  EDIT:I forgot to say, I was fidlling around with the plastic knob to change the oil / petrol mixture, could this give me any issues I'm currently having?

Ok, I just propped the tank up to have a look at the spark plug... Well, i can't even get it out! It's so god damn tough. It looks kinda new though, the bit where the rubber goes over it is completely white. I did want to inspect it, but like I said, i couldn't get the facker out!!Can anyone give me some instructions on where the gasket head is? I wanted to see if I need a new one. EDIT: Nevermind, to get to the cylinder I need to take side fairings off. Just a lil question, if my head gasket is broke, is it safe to ride? I need to do around 30/40 miles on it in the next two days.

Suppose this can be marked as fixed. Dad got home today, went on it and he said there is nothing wrong with it. High pitch noise - Wind -_-Sluggish - Need to change gears when I'm at higher revs - he got it to 80 with no issues. Thanks anyway!

Glad your problem's sorted. Suspect you're feeling slightly foolish.

I was, went on it today - feeling rather slugish again, top end it's fine, but it's getting there (Gearing maybe?) That noise is still there, but around 6-7k revs the engines noise kinda kills it. I'm now 110% that noise is not the wind!!!

Maybe a little late to be helpful but as your father says, your RS seems to have the same 'dynamic' issues mine did. When I was learning, I had an RS and an NSR, and the biggest difference was that the NSR squeezed out just enough torque to ride almost like a 4 stroke - the RS on the other hand had a habit of leaving me for dead at every damned island and junction I crossed. If I wasn't doing over 7-8K revs, the top couple of gears were basically useless, it's absolutley essential to thrape the nuts of an RS to make it rideable! Loved it to bits though, get it in the sweet zone and nothing handles quite like it. Bandit 400 is pretty darned close, bought one for the missus last week and after taking it round some of my favourite twisties I'm wondering whether to hand it over or not

You nailed it perfectly. I don't even bother using my 6th gear if I don't go over 7k, I actually loose speed...

Mid-range bogging could be down to a few things.
Cdi could be restricted, Dips into the revs at 6k-7k (roughly), Jets could be blocked Or float could be stuck, Spark plug may be for restricted models (Br8) The full power derestricted RS run better with br9 - br10 sontry both. Or could be something as simple as the Powervalve blade getting stuck due to carbon build up.
Considering theres so many Aprilia fans its shocking to see noone mentioned Any of the above..

Log in or register to post comments