Aprilia ETX 125 (Don't expect to go motocrossing...)
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Two weeks ago, I fired up my Aprilia RS 125 for the first time in twelve months, put some fresh fuel in it and took it for a blast around my ways. THE RUSH!
[Inserts old photo]It was so refreshing to ride something with the RS's power delivery. It's not just that it's fast (notwithstanding it's just a 125 not a 600), but it's the way that power is delivered that puts this big grin across your face.
The DT is just simply not the same.
It's night and day the difference between the two models, the Rotax 122 is just from the ground up, a competition engine. The DTR has been shoehorned into that zone.
(I need to discuss the current setup as it's properly awesome. Forget RS 125 power delivery, it's simply never going to be that, but set it up differently and I am absolutely in love with this bike. It's running better than any other setup I've had for it.)
So I made the decision that I need that Rotax power in a DTR frame, initially I was looking at an Aprilia MX 125.
I found a few for sale, in varying conditions, none of which frightened me. The problem I had, was I have no need for another Supermoto. If I had this bike, I'd have no reason to visit my Yamaha, and I don't want to sell the Yamaha, so what? It'd become a bike I never ride.
I widened my search, simply "Aprilia 125", that's where this Aprilia ETX 125 came up.
It's basically a DTR with a Rotax 122 engine inside it. It comes factory with upside down forks, brembo brakes and Sachs adjustable rear suspension.
This bike serves a purpose.....the green lanes.
I supermoto'd my DT because, I was young, I could only have one machine, and the DT had recently been destroyed after it got stolen, but I wasn't earning enough to outright buy, let alone store, another motorcycle.
A few years later, my friend bought a bone stock DTR and we swapped bikes on a ride out, it was SO MUCH FUN riding his bouncy soft Yamaha in stark contrast to mine.
Where mine handles and grips, his stepped out, wheelied and didn't stop (although that last point is one of the true perks of my DT). Ultimately, I had more fun on his Yamaha in five minutes, than I had ever had on my SM'd DT. For the purposes of commuting, which is what I did at the time, my SM'd DTRE was easier to live with. But as a weekend warrior, a bone stock DTR just put a grin on your face.
I've had my Yamaha 13 years, and with a bit of luck I'll keep it until my passing, that's for sure. This is much like my RS, I virtually NEVER ride my RS. I've done less than 1000 miles in the 4 years of ownership on it. But I love that bike, I open the garage and I just love seeing it. My life has changed, I don't drink/smoke/drugs/party and I virtually cycle/run everywhere I want to go. Motor bikes to me are something I tinker with and very occasionally ride. I mainly cycle everywhere.
The Aprilia ETX 125 is a trail bike fitted with a Rotax 122 engine with a variation of the Gilardoni barrel found in the RS 125. It's very similar to the Yamaha DTR in that it's a trail bike with a tubular steel frame and steel swinging arm.
It comes equipped with upside down forks and front/back Brembo brakes.
The trail setup makes it ideal for light greenlaning.
Just don't expect to go motocrossing and competing with the big boys on their KTM EXCs or GasGas's.
Despite the wonderfully fitted Rotax 122 engine, I'd be very surprised if this bike is putting down more than 11 horsepower. The Gilardoni barrel differs greatly from the ones fitted to the RS's and there are no powervalves fitted here.
It's running the same round slide Dellorto PHBH Carburettor found on many Aprilia RS's throughout the years, but comes fitted with a kick starter only.
This bike appears to be BONE STOCK and has completely linear power characteristics, unlike the ear to ear grinning RS described earlier. It tops out at around the same as a Yamaha DTR and, whilst it's been an awfully long time since I've ridden a stock DTR, I'd say it's a tad slower than the Yamaha getting there.
The ETX differs slightly from the RX/SX/MX models, which I'd argue are superior to the ETX, but this bike was DIRTY cheap and came from a good honest seller, whom I've directed to this website as they too have a DTR.
I bought the bike sight unseen, wired over the monies and sent a courier to collect. The photos taken were done at my first sighting of the bike in person.
It's old, tatty and I love it!
Expect a build thread on this over the coming years, but I can say immediately, that top end needs overhauling. Next month I'll be swapping out the piston and rings to freshen it back up. New gearbox oil, spark plug and binning the 2 stroke oil that's in there
As time goes by, I've learned to love the styling of the DTR. That classic retro style will always fetch more than my highly modified Yamaha. With that in mind, the plans will be to restore this to some former glory, bearing in mind that I want to go green laning on this machine so I don't want it mint.
That engine is going to see a complete overhaul including:
- Italkit 140cc
- VHM Head for Italkit
- Italkit Pneumatic Powervalve
- Arrow Exhaust Pipe
- VForce3 Reed System
- VHST Dellorto Flat Slide Carbuerettor
- Zeeltronic Ignition System (Assuming they fit)
I know what these Rotax engines are capable of, with a little fettling, this ETX will be an absolute wheelie machine.
I'm looking forward to getting the frame re-powdercoated and the swinging arm done, I want to know if the aluminium arms from the RX/SX/MX fit this frame and wheel setup, as that'll be a little upgrade for it.
There will be a project thread for this in the fullness of time, but for now, I'm just going to enjoy the bike for what it is.
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@Calum great read man looking forward to seeing some progress
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@mhbikesnbits Cheers bud, I'm excited myself to get stuck in, I've ordered all the bits to give it a good service and just eye ball that it's safe to ride for the time being. Ordered a brand new Full Arrow System, it's not for this bike so may need chopping and welding, but I won't be fitting it until the bike goes into for a restore anyhow. Be night and day when it rolls in and out of the garage over a weekend of tuning
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A friend of mine recently got an RX and I have to say without even riding it they’re hands down a better bike in every sense of the word, I was really impressed.
I’d say the RX is the superior bike too. Didn’t some ETX models come with non-usd forks and is she a U.K. bike?
Do you have plans to restore or just tune the engine and thrash it?Having seen the support and potential for tuning for those engines I must admit I’m a little jealous.
Also happy for you that brings bring you a decent combined sense of peace, happiness and satisfaction.
We all, and in some ways I think men especially need something like that in our lives. Look forward to seeing what happens with it. -
@Stevie-Wonder The RX/SX/MX just have better bits, immediately I can see that the shock is better, the swinging arm is better and probably the engine might be less restrictive.
I've ordered an RX swinging arm, SX shock for it. New piston, rings and gaskets. New plug, two stroke oil and gearbox oil. Full Arrow system, 28mm Flat Slide and VForce3 reed system for it. Would benefit from a new 28mm inlet as this one is starting to perish.
I need to raise the bike a few mm as it's a bit short for me, company in Germany make a jack up kit, but appears they won't ship to the UK, so I will probably just make my own jack up kit.
I'll whip the clutch cover off and make sure it's not going to shred the balancer shaft gears. There is a heavy rattling sound under load, that needs looking at.
I'll take off a few pieces run them through my shot blasting cabinet and get them looking pucker.
Plan is to thrash it on some green lanes, keep an eye out for brand new genuine panels and get it all refurbished in the future. But for now, I'm enjoying the dutty look as all my other bikes are pristine.
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@Calum gets exciting when your waiting for bits, would meet up a few guys from the forum and go for a good green lane ride out would be wicked
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@mhbikesnbits Years and years ago, the DTR forum used to go camping together. Can't remember how many people would go, but there used to be a whole turn out from all over would pick a medium spot for all and meet up and stay the night camping
https://dt125r.activeboard.com/t48288076/midlands-meetup-maybe-further/
Like 6 pages of material but it's not accessible anymore.
Spent this weekend tidying the bike, stripped off all the electrical tape that was used to hide the dodgy paint work, shot blasted and rattled canned for now.
Wire wheeled the expansion chamber removing the rust and polished up the end can.
Just to make a little less trashing.
It's like the previous owner went over this with a paint brush and some Delux paint
Unfortunately, the engine bits didn't arrive, but whilst the exhaust was off I had a look at the engine.
Piston skirt has scores down the exhaust side and the rings look like they've seen better days. Bore could benefit from a hone also!
Will be interesting to get the barrel off actually and see how it compares with an RS barrel, I noticed there were no auxiliary exhaust ports on this barrel. When this engine does go in for a tune up, it really is going to be night and day! The tuning potential from this base is staggering.
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@SpookDog That's the plan, crosser stylie!
£200 worth of my RS spares sold last night, so I could very much afford anothe Italkit 140cc.
I bought a 5mm stroked rod for my RS and the plan was to use this 160cc Polini kit on it, and use the 140cc kit that's on it for this ETX. But always handy to have spares...
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@SpookDog Ey?
Oh yeah I guess I haven't really shared this. HUNDREDS of pounds. I'll get some photos up in a second.
@markus-w No this is a stroked rod, 5mm longer than the stock rod.
@mhbikesnbits I actually have several RS 125 rear master cylinders, but I just got back in from a ride out now and the rear master cylinder doesn't feel like it's working so...might just buy a new genuine one.
On my DTR I run the stock Nissin master cylinder.
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@markus-w No, it's stroking the engine by a whopping 5mm. (that's sarcasm).
So the problem with big bore kits is that two strokes prefer "Square Engines". What this means is that, in an ideal world, the bore matches the stroke.
The Polini 160 kit has a notorious drop in over rev, stroking the engine back out so that it is now the same size as the bore, will enable the engine to make more torque and rev harder.
The price of the parts are pretty astronomical, especially considering I barely ride the thing. It's more of a thought experiment.
The Italkit 140cc I'm running at the moment is just incredible! The power delivery on that thing is such an adrenaline rush.
This is a long term project, and I'll probably never drop it in, but be nice to build this stroked polini, the eventual displacement will be 166cc, it's a real minimal stroke. It should hopefully enable the engine to retain some of its revvy characteristics.
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@Calum yes I know about bores and strokes but obviously installing a longer con-rod will not change the stroke, the only way to alter the stroke of any engine is by altering the crankshaft, even then you'd need to fit a longer stroke crank to give you more cc's, and for it to work you'd need a shorter con-rod to prevent the piston smashing into the head. Or am I missing something as it looks like there's some sort of spacer under the head? The only reason I know of for installing a longer con-rod is to allow for a shallower hence lighter piston.
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@markus-w Dude
Uhhmmm yeah you're absolutely right. I feel like such a dinglebat.Well, this is a long term project so more thinking is required! I'm not achieving very much here am I???
Thanks for correcting me, I don't know what I will do with these parts, more thought is required.
So it's still 160cc's, which is fine I am not interested in my displacement, but there are gains to having a longer rod.
Note here my failings were thinking longer rod meant long stroke which is NOT correct.
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@Calum no worries bud. As I said though I have heard about long rods being used to allow for a more shallow therefore lighter piston but thinking about it that must be on 4 strokes as the piston height is needed on a 2 stroke to close the ports. You had me thinking for a while there though. Anyway, sounds like you're going all out on this one. Quite a rare bike I believe too. Look forward to seeing the progress.
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@markus-w Yeah, well the intent on this bike is some green lanes. My RS is the all out one which is where the Polini 160 kit and Italkit rod is coming to play. But I was out on the RS last night and I am well happy with thr Italkit, it's superb. This setup is just something to build and put on the shelf.
