The Helios Project (Aprilia RS 125 Rotax 122 Biaggi Race Replica)
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Forged Piston Fitted.
Fitted it all nice and snug.
Put the engine away, amazingly (luckily) found one of the circlips had fallen out onto the bench.
Thankfully I found that, not sure how that happened. But that's back in now!
Of course I have bought titanium head bolts for this engine. But I was too eager to bolt all the pieces together and they haven't arrived yet.
But I will fit them when they arrive.
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@calum Oh my thats beautiful!
Do you know how big the difference between the piston diameter and the cylinder diameter is? Or did the piston arrive with the cylinder perhaps? I've always been uncertain how big the difference should be when fitting a new piston. -
@irongamer727 Yeah it probably says in the spec sheet it comes with. I didn't read it. You can tell the piston to cylinder clearances in this engine are large. However I woupd expect that from forged components due to their thermal expansion coefficient.
For reliability I have knocked the compression back, this piston only utilises a single ring. Less frictional losses and bore wear
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@irongamer727 exactly that.
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I guess you purchased the cylinderkit on PJME. I mean that was a pretty good price for it!
I know you have bought the special cylinderhead and got it ported but still, I thought the cylinder would be like £600 or something.
The polini big bore was a bit more. I guess you reckon you can get more power from your kit, but how?
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@irongamer727 So I didn't get this barrel ported. I just said that the porting work is damn good, albeit some minro flaws.
The last RS in my garage used the Polini big bore, before the 140 kit was released.
https://www.youtube.com/watch?v=GobIl4e-mU8&t=2s&list=PL66C1264C7D6205BB&index=3
Very quick bike, but the Polini eventually seized after very little miles and most of it was being ridden softly.
It was my brothers bike, but mi casa, su casa as the Spanish say.
Big bores are hard on engines. It's not the first time I've said it, and it won't be the last, in my experience the Athena was pretty poor for performance. Reliable mind you.
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@calum so the polini isn't very reliable then?
I've heared the same. I'm happy with the Athena though. Strong, not very fast but comfortable. -
@irongamer727 Good torque gains from the Athena, if that what you're after. And, unlike the Polini, doesn't affect reliability.
I can only comment on my own experiences, and that may have been down to incorrect jetting. As this wasn't my bike I wasn't at liberty to jet it as I saw fit.
The reason I went with the 140 kit, is that I am not interested in more CC's, I want it to rev to the moon and the fact that the person who designed this designed the original. It was also (as you say) cheap. Just £40 more than having my old barrel replated and ported with a new piston. Something different as well, I've not experienced this cylinder before.
I'm excited
Still £2k of bits left to buy for this bike yet. -
@calum it's going to be interesting to hear how she runs!
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@irongamer727 Yeah sure, I expect it to be...disappointing lol. If I bought a rag around RS and bolted on a cylinder kit then yeah, fair enough. But having been building it for nearly 3 years, the expectations are too grand.
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Another delivery of goodies arrived!
I think this is shamefully about all I can afford this month
Brand new set of mirrors
Now, I skimped out here. Samco hoses are around £100, but I got these from China for like £35
To be honest with you, they're banging for the money. Maybe I'll get the samco ones further down the line, although I doubt it.
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@declan Direct from China, like alibaba style.
Engine built, I will clean the carb tomorrow to make it spanking.
Titanium bolts mount the intake to the engine. Along with my powdercoated skull cap, which should contrast nicely with my NGK racing coil and HT Lead, along with the red engine mount.
Just awaiting on some carbon from America, my on going Hydraulic clutch conversion, then this engine is ready to rock and roll.
And for those interested in the hydraulic clutch conversion, it would appear, after much discussions with far more qualified engineers, that the solution the other chap derrived is not adequate.
I will explain in a separate thread, but basically it's gone from being very easy, to needing a bit more thought...but more on that when it's finished.
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