70mph daily driver - Forward intake

[PIG]

Oct 10, 2016 3:59:53 GMT -5 Lucass2T said:

No real update, only a quick view on plans I have for the axis.

Im going l.c. next summer. Either Polini Evo 3 or Airsal Xtrem (47,6mm). I really like the Airsal Xtrem. I want to keep the 80mm rod crank I have in now, that limits my choice of cylinders somewhat. I also looked at the Hebo Manston, Revolution and Pata Negra but they have a flat dome piston which I don't like. The Metrakit ProRace 3 is also an option but they have strange transfer duct shapes for which I need to do some case porting and thus disassemble the crank. I don't want to take the engine apart.

Exhaust, Kundo F1 pipe which I have one lying around.
Innerrotor ignition, probably HPI.
Dunno yet about intake. I don't want a overly tilted rear facing carb and sketchy subframe. Maybe I do a front facing carb. Then its either gonna be a Mikuni TM24, TM24SS (tilted carb) or a genuine Keihin PWK28.

Airbox will be either some sort of kart airbox or i'll sacrifice the storage room under the seat.

Im gonna aim for 80mph.

Really looking forward to seeing what you come up with. It's awesome how so many guys are going to the l/c hyper race stuff. Ever since I cracked the 80mph barrier I've had women throwing themselves at me. Wife says it's the Bidalot or her, nice knowing ya sweet heart. Lol.

[Lucass2T]

Yeah I can't stop saying how good it is to be a single guy

[Lucass2T]

I was just thinking, I don't necessarily need to limit myself to cylinders intended for 85mm rods. Milling 5mm from the base of such a cylinder eliminates the problem. But on the other hand...why would one design a cylinder specificly to be used with a 85mm rod? Because otherwise (with a 80mm rod) liner and piston wear would get out of hand im sure.

So yeah, Im well aware of this...
Then the next question obviously is:

1: Do I go with the old fashioned plug and play, don't ask questions and just use products like the manufacturers want you to use their products?
OR?
2: Do I widen my choice of products by modding a 85mm type cylinder and by doing so widen my knowledge and experience and just experiment away and see where the ships strands?

note: even though the real top tier cylinders are intended for 85mm rods...there are still some real nice 80mm type cylinders (the ones I mentioned a few posts back)

[spaz12]

That Pro Race 3 certainly would be a nice cylinder and it uses an 80mm rod, right? I bet it would go great with that Kundo pipe that you have.

It would also be cool to see what you can do with a cylinder.

EDIT: I went back and read that you don't want to pull the motor apart because of the transfers on the Pro Race, but isn't it possible that you could have issues with almost any of the cylinders having slightly different transfer ports?

[PIG]

Any of the mentioned cylinders will require the case transfers to be opened up. I mean you don't have too, but to do it properly the cases are going half to be split. Why don't you want to split them?

[Lucass2T]

The Polini's transfers channels are almost identical to my ported cases. I think the airal's channels are smaller than the ones in the cases and the Metrakit will need casework. It's not that I don't want to take the motor apart, but when I don't really need to I don't want to because the cylinder which is most appealing (Polini) probably doesn't need additional port work on the cases.

From all of those cylinders the Polini is the most appealing, big transfer area, big transfer channels, big bridged exhaust port, a dome piston and made in the Gilardoni factory.

[tsimi]

Oh man, I am soooo looking forward to this upgrade. I always wanted to know how the Polini Evo3 looks and drives.

[190mech]

Just speaking from 2T theory,a longer rod is better..Even if a short(80mm rod) cyl is installed on a 85mm crank(with 5mm spacer),it'll be better,less piston side loading,longer dwell time at TDC and BDC,opens transfer ducts for better flow,etc..

[Lucass2T]

Man, this thread is dead! But thats gonna change! I just ordered some parts to have this thing back on the road again.
The reason i took 70 mph axis out of service was because a melted piston dome. One of the head nuts came loose and it developed a very slight air leak which caused a caved in piston dome. I didnt feel like buying another €70 piston.

Since a few weeks theres this dude blasting down my street every so often on a Aprilia SR50. I've seen it from a distance parked and spotted a Yasuni C16 and Dellorto PHBG (probably 19 or 21mm). And from the sound it makes he's probably running a 70cc kit. Everytime he's taking off I hear him coming from a far distance haha, that really got it going again for me. One day Im gonna meet him at the traffic lights and then we'll see how fast his scoot really is

So what did i order?
- Fresh piston
- Doppler S2BR variator. It's an overrange variator and uses big 19mm rollers like piaggio.
- Stage 6 overrange belt. Length=806mm over 788mm stock, to make better use of the 122mm rear pulley.

Im gonna ditch the Metrakit SP pipe. It worked fine but i have a collection of other nice pipes i want to test. Which one would you guys pick?
- Yasuni C16
- TJT Gruppo B
- Polini 4 race 1
- Kundo F1
- Tecnigas RS70

Myself im strongly leaning towards the c16 since that pipe just proved itself on similar setups. The 14.000rpm kundo is a real screamer but probably a bit too much for the stock port timings and stock flywheel. The TJT gruppo B is more a 50cc i think (narrow belly). Anyway, lemme know what you think.

['O'Verse]

I say C16 or stay with the metrakit. It has served you well in the past. The only reason you toasted the piston was because you ran it too hard. 70mph with an air cooled 70cc is quite a feat. C16 might have more of a hit but dead down low.

[benji]

I'd say c16. Very well loved pipe, I'm gonna buy one someday (hopefully). I wish I could get my daily rider to 70mph!! I got about 61 before I run out of rpm.

[Lucass2T]

My Doppler S2BR variator came in yesterday. I've taken some basic measurements which i'll post later and i'll do a short review on it.

It's an overrange variator but it's not specified to be used with a specific OR pulley. Maybe it's designed to be used with the stock pulley and an overrange belt to gain more top speed? It takes big 19X15.5mm rollers like the later piaggio variators. You'll have to remove the electric starter stuff for the extra travel the variator supports. It gets a lot of good reviews for excellent tunability and wear but i'm not really impressed with the inside finish tho. There's a lot of casting imperfections on the roller ramps. I'm gonna have to remove those to prevent the rollers to wear out too quickly. The rest looks good.








Some days ago i was browsing a scooter forum and there some people said the pre 98' Piaggio rear pulleys will fit a minarelli engine. They're 128mm like Minarelli OR pulleys. You'll only need to fab up two spacers and use the piaggio contra spring (they're wider). Again i'll post those specs later.

So I was hmmmm let's give it a try! You can use your regular minarelli clutch, they'll fit straight on the Piaggio pulley. Stock 2nd hand Piaggio parts are plenty available so they're not very expensive. Went to a local scooter scrapper yesterday and bought a Piaggio Sfera/Quartz/Zip unit for €20. Too bad the splines are curved . But otherwise a nice and cheap poor mans OR if all works out like they say it will.

[aeroxbud]

Great idea. Did you have chance to try this yet?

[Lucass2T]

Jul 4, 2018 18:40:10 GMT -5 aeroxbud said:

Great idea. Did you have chance to try this yet?

Im still waiting on some parts to come in the mail.Then i can start building up the engine.

[Lucass2T]

Somewhere in the past i bought a Brembo 4 pot caliper off of a range of 90's italian sports bikes. The plan is to put it on the axis but i'll need a bracket/adapter.

I found this on aliexpress.


I was wondering if anybody knows if this will fit a Yamaha Jog a.k.a Yamaha axis? Or am i going to need to fabricate my own?