Aprilia ETX 125 (Don't expect to go motocrossing...)
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@Calum I have the Athena 170 kit as well, just haven't fitted it yet, and got mine from a similar source. Definitely good value for money as you say for a brand new top end, in fact I was so impressed when it arrived I decided to try an Athena 125 kit as well which will be going on the bottom end I rebuilt recently.
Plan is to build that bike for the road/greenlaning to avoid insurance/DVLA hassles, and use the 170 kit's extra cubes/torque to make another bike into a proper little Enduro bike and enter it in an event locally. I've already got some XT600 fork springs/15W oil and a YSS shock which improved the suspension off-road no end so the only thing I'm worried about is the combination of lower gearing and increased capacity leading to overheating hence my "Bigger Radiator?" thread a few weeks ago. Another idea is to get a couple of small computer fans, make up a bracket and wire in a manual switch.
I think the basic DTR engine platform is well up to this as GPX use it in the TSE250R and everyone's raving about that ATM. Half the price of a brand new KTM but still expensive. Would be very satisfying to rock up at an Enduro with a 30-year-old bike with more setup options than one of those!!
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@Calum said in Aprilia ETX 125 (Don't expect to go motocrossing...):
@HOTSHOT-III I am going to consult my Graham Bell Two Stroke Performance Tuning. This was always my intent with this Polini kit build. To fabricate and do something unique and learn. But I'm glad I have been informed now so I didn't go away buying more bits before reading.
So I need to do a blog on the Athena kit. I've spent the last few weeks dialing mine in, after owning it for like 2+ years...
It's running better now than it ever has, including TZR RR Belgarda engine days, and my Mick Abbey 3MB Ported days.
This Athena kit would seriously benefit from some porting work IMO. My main issues with the Athena kit is by 10k it is totally out of puff, but I may need to richen that top end back up. Once I've dialed it in, I'm taking it to a rolling road and I'll report back with my verdict. But with the modifications I've got on my DTR it's now a little wheelie machine and I absolutely love it. The main thing is, it and I are a lot heavier than we were 12 years ago when I bought the bike, the extra torques has been really useful to me. But now I've dialed in the powervalve/ignition/jetting settings a bit better, the bike is running lovely. I'd expect if BHP isn't mid 20s then the jump in torque will justify the expense paid.
I also got my Athena kit from Germany for around £400. When you consider what's in the box, cylinder, studs, powervalve, head, skull cap, gaskets, piston, bloody good value for money. Consider the Italkit 140cc bore is £350 for a bore... But the Italkit makes $$$ power
I'll happy to help you with info on that blog.Full of experience from the kit and the tuning I did.
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@Calum hiya pal just yesterday I bought myself a 1999 aprillia etx I’m used to my 4 strokes just wondering if u can give me any info on how reliable they are and what piston size they take just Incase I blow her up
any help would be appreciated all runs and rides mint atm running it’s at 30/1 is that the best ratio for them a aswell ? -
@18tylacollins Hi bud,
As described in the blog, this is a heavily restricted version of the RS 125 and even the RX/SX/MX series of motorbikes.
As such they suffer from the same problems as those bikes but on a much smaller scale. Such problems are well documented on the net.
The main thing to bear in mind is that these bikes are old and will need maintenance. Since you're coming from a four stroke to this bike, the thing you need to keep an eye on is the balancer shaft cogs which drive the oil and water pump. These are nylon and will eventually snap, starving the engine of oil and causing a seizure.
It is because these engines are so restricted that actually the maintenance schedule for this is incredibly drawn out and therefore need seeing to less frequently.
For all your engine needs I'd recommend PJME.
My ETX is currently stripped down to the frame for a full nut and bolt restoration so I can't tell you how reliable they are to live with, it was never my intent to run this as a daily whip.
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@Calum the balancer shaft we’re is that located buddy and how would I know it’s gone back or going bad befor the worst
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@18tylacollins 30:1 oil mixture sounds way too rich. The bike uses an oil pump you don't need to premix the oil and its probably not a good idea to run the pump dry. Just buy oil suitable for pump use.
The service schedule describes when the primary shaft gear cogs need to be replaced. I'd suggest getting a Haynes manual and having a look there.
Typically if the primary shaft gear cogs fail then there will be no drive on the water pump and as such the bike will overheat. If it drives the balancer shaft then the engine will vibrate like mad so it'll be obvious, the problem is it can go on a ride out miles from home and my advice would be to kill the engine and walk back.
I don't think Rotax make the cogs anymore so you will have to buy pattern parts. Again PJME supply them..
Yes the engine is a Rotax 122, but the cylinder is a highly restricted barrel. No auxiliary exhaust ports or powervalve. I haven't checked the transfers yet to compare.
Either way the cylinder needs to be binned and put an RS barrel on it
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@Calum Hi Calum, Anymore updates of your ETX build? Really enjoyed reading through your build so far. I also have an ETX. Currently in the process of making it a supermoto and getting the frame powder coated. Then chasing more power.
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@Rxvert2k-0 Hello
Yes lots more updates. I've taken photos, but I am awaiting a good point at which to update this thread.
I've bought:
- A bunch of Aprilia RX125 parts (better spec than ETX)
- Aluminium Swinging Arm
- Gas Shock Absorber
- Rear Brake Pedal
- New Bearings
- Linkage Rerefreshed
- Dual Radiator Setup
- Arrow Expansion Chamber (A lot lighter than stock)
- Polini 160 Big Bore Kit
- Italkit Pneumatic Powervalve
- Dellorto VHST Flatslide Carb
- Lightweight Clutch Pressure Plate
- I just dropped the frame off for powdercoating last week.
- Engines out for an overhaul
- All new bearings and bushes
- New Old Stock Genuine Fairings
- New Old Stock Genuine Graphics Kit
I wanted to update this thread when I had it in a viewable position.
There is lots to update on, but I want to get it in a more showable position before I blog about it.
- A bunch of Aprilia RX125 parts (better spec than ETX)
