The Helios Project (Aprilia RS 125 Rotax 122 Biaggi Race Replica)

[declan]

@calum I’ll ride bitch on the the back lol

[Calum]

@declan Uhhmm, did you not see I blanked off the Pillion seat mate.

[declan]

@calum I did but I’m sure it will be comfy enough or I’ll get a metal basket for the front and we can just go straight ET style

[Calum]

@declan Uhmm, let me think about that...

(Calum is typing...)

[declan]

@calum lol guessing it’s a no then

[Calum]

Everyone I asked about whether I should or should not, said should NOT!

Are they mental...

What's in the box!

Bare in mind, I only want a few components out of this box that are no bigger than a hammer lol!

Any ideas?

If you guessed a kickstart, then you guess correctly!

And I know what you are thinking. Why?

Well appreciate this, this bike ain't an everyday bike, chances are, when I do eventually come to ride it, the battery is going to be flat and I'll have to bump it. Which, no I ain't doing.

Plus, it's totally bad ass crosser stylie yo!

On a serious note though, £600 for the kickstart from Aprilia. I kid you not, it's genuinely cheaper to buy a whole engine (if you can find one) just to salvage the kickstart out of it.

This would be my third Rotax 122 engine for this single project. That's, uhhmm, expensive.

I am going to strip this engine, salvage some of the components, sell the rest.

I want to go all out on a special conversion (for no other reason than because it will be cool) on this bike.

And I'll give you a clue, having a spare engine is going to be useful.

I will gut the cases and leave what I want to modify in place. And hopefully have something to document.

Eventually I will rebuild the cases and store in case of the inevitable happens.

This engine comes out of an Aprilia MX125, ETX125 or RX125. But all of which are really hard to source and expensive when you do. That said, I've got this now, and it's blown the budget for this month, which is a shame. But such is life.

[Irongamer727]

And I'm worrying about spending £70 on a full kickstart conversion for my dt... Guess your pocket is a bit bigger than mine though

[Calum]

@irongamer727 I did say it was cheaper to buy a whole engine just for the kickstart than the kickstart itself.

Whilst this did cost more than £70, it didn't cost £600. But I was prepared to pay that for it.

I will strip the engine tomorrow and finish off my current build.

You understand though, you need a kickstart on a two stroke.

[declan]

@calum your telling me a kick start is over 600 pound 🤯

[Calum]

@declan New from Aprilia yeah. They only did them for the Sports Production series. The series they used in the SuperTeen MotoGP. So they were a highly specialised order!

[Calum]

LOL at this engine. It was sold to me as :

Came from a Sx in good condition just had new piston con rod main bearings been running for about 5 mind what you see is what you get

It was also listed as a Rotex engine, not what it should be as Rotax.

So I can't say I am really surprised. Item was well wrapped and delivered within 48 hours and I got what I actually wanted. But check out the rebuild on this engine.

Firstly the head is absolutely ruined, straight in the bin this went.

Secondly the bore is totalled, but it's an aftermarket Mitaka one so runs a steel liner, meaning it can be rebored so isn't totally scrap. But definitely affects my resale value Was hoping to claw back a few sheets on this engine to pay for the conversion.

I didn't get a photo, but the crank journals have a nasty score in them which I would want to fix. Shame. The crank looks okay, although given the damage done to the rest of the engine, I would have it rebuilt.

And the little end, which was probably what caused the fault in the first place.

Prepped the cases to shot blast next weekend.

I'm going to use this engine as a base to fabricate up the part I want. It's gutted other than the bearings, purely has a means to protect the journals. But in time I will rebuild this engine and leave it as a spare.

Now back to my engine

As you can see, it's now dual wielding both the Starter motor and the kick start mechanism, which is nice.

Just missing a titanium bolt that secures the kicker in place, I shall get that ordered.

Engine has been timed up and all new gears installed.

Just waiting on PJME to get new clutches in and then hopefully sort the top end out next month. Got some tasty ideas for the top end.

[declan]

@calum don’t know what your on about mate looks ready to race to me what did the piston look like

[Calum]

@declan Piston wasn't too bad. Could have used that. But I threw it in the bin. Wasn't even forged.

[declan]

@calum so maybe a stupid question but was it rebuilt badly or not rebuilt at all

[Calum]

@declan Nah man I don't think it's a stupid question.

So it's been stripped before.

There was a rusty bolt on the inside of the engine. That suggests that they just used a bolt that would normally be outside the engine on the inside. Since it was an OEM bolt.

Also, the crank is really solid.

I reckon, someone who didn't know what they were doing, rebuilt it poorly. Started it up. heard a horrendous noise, and then gave up on the idea after sinking too much money on it.

The barrel doesn't look to have been rebored. So it was likely a new barrel at the time. The piston wasn't the highest quality, but it was a decent piston.

I doubt the mains were changed, and they clearly didn't bother with the gearbox bearings. I reckon the minimal amount was done. But once it still didn't run right, they gave up on the idea.

It's funny though.

As I say, the cases are handy for my next project I'll be doing on this bike.

And all I really wanted was the kickstart. I've managed to sell some of the bits I've stripped from it on eBay. So that's some way of clawing the money back out of it.

[declan]

@calum sold bits already? Well it’s a good thing You didn’t want the engine as a whole isn’t it

[Calum]

@declan Literally just wanted the idle gear and the kickstart mate. The rest I already have.

But for this tasty little conversion I am going to do, it would be nice to have a pair of crankcases to hand

I ain't saying no more than that, you will see the results when I finish.

[Calum]

Updates are coming...

But who can guess what custom modifications I will be doing on my RS?

I won't take credit for the idea. I always wanted to do it on my DT, but just couldn't justify the price.

I then found a thread detailing a certain other bike made by Honda, whom did the exact conversion on these engines.

HM CRE 125 if you're wondering. Looks awesomse, same engine as these RS's, except they ran electronic oil inject for 50% less oil consumption. Amongst other mods.

But after not being able to find the parts I wanted, I gave up.

Then I found this build thread on a certain other website, and mans was like...yes I'm doing that.

[finnerz89]

@calum hydraulic clutch?

[Calum]

@finnerz89 Spot on mate. How did you know?