Stroked, Bored, 171cc Monster Mini.

[Scott]

Cactus Jack, Yes Im sorry i did post the wrong pictures up i apologise I'm only telling you what I'm being told, The bloke is Italian and we have a bad language barrier. I am not sure about the pins he was talking about but you seem to know what your talking about so they sound like what he meant. Here attached is a picture (I assume it is the 60mm kit, but may be smaller, I am 99% sure, He did attach the wrong pictures before (The Ports).

Scott.

 

[Scott]

 

[Cactus Jack]

Well that cylinder looks OK ........ he's kept the sleeve an equal thickness all the way around ........ he may even have moved the bore centreline to get the sleeve dead centred to all the studs ......... the cylinder would more than likely also need the same dowels between the base and cases since the stud dowels would also have been removed from down there ..........

Some of the big bores I've seen done over in the US are paper thin near one of the stud holes .......

You should be in good hands then .......... the Italians are top notch and sensible engineers .........

 

[Scott]

As you can see on the above picture the two pins through the cylinder head.

 

[themountain]

Yes but Jack was talking about cylinder to case to evoid any motion!

 

[Scott]

Yeah, Sorry Ive been a bit confusing, I agree.

Whats Everyones thoughts on what they've read so far, hows my chances, HP Guesstimates?, lets hear input, Only really 2 blokes other than me getting involved in this.. themountain and Cactus Jack

 

[themountain]

19.5....:d

 

[ducar.r.spec]

18 hp itll get up on the back wheel easy

 

[Le|Garage]

man! what size valves are they in that picture? they look crazy big..

 

[themountain]

I guess its 30/24 isn´t it??

 

[Cactus Jack]

The engine is a Lifan 120. Cases need to be bored 62mm to fit the sleeve. There is enough room. people have run 62mm bore which needs about a 64mm grind to fit the sleeve no problems..

Two of the studs (top RH to bottom LH ) are 64.5 mm across the diagonals (inside edge of stud to inside edge of stud) and the other two (bottom RH oil gallery to top LH) are 65.75 mm across the diagonals so the stud threads would be really close to the edge with a 64 mm O/D sleeve .

As for HP .... who knows ....

 

[Mack]

Hey welcome back....I been away for a while too and this is the first thread I,ve read. I have a few PM's in my inbox ...

I started looking at maximising strength in the stud area a while ago and have settled on short skirted pistons in a 59mm bore and cases at 61mm with the sleeve skirt cut to be just shorter than the piston skirt at BDC. minimizing the boring depth. This leaves plenty of meat around the studs and enough room to go to 59.5 when the time for rebuild comes round. Also as Cactus stated earlier 59mm bore leaves you with a decent thickness of sleeve to minimize distortion.

 

[Mack]

oh...and.... 15hp if you just randomly pick all the dimentions of the engine parts and bolt it together.
17 - 18hp if you (or someone else) have calculated for maximum volumetric efficiency at your desired rpm and will spend considerable time trying different combos to get it.
19 - 20hp if you are darn good at the previous and half stumble, half figure out, the secret mods each engine type needs to get the last few ponies out.

 

[themountain]

oh...and.... 15hp if you just randomly pick all the dimentions of the engine parts and bolt it together.
17 - 18hp if you (or someone else) have calculated for maximum volumetric efficiency at your desired rpm and will spend considerable time trying different combos to get it.
19 - 20hp if you are darn good at the previous and half stumble, half figure out, the secret mods each engine type needs to get the last few ponies out.

HE IS ALIVE TOO...welcome back Mack

 

[coolmodee01]

sounds like a good project and welcome back
keep us posted on the subject as i'd be interested to see if you get much over 15hp
plus it would give me and indication of what sort of mods i can do to my jailing 125
i'm a bit undecided

 

[I_THUMP]

How much are all those parts costing from this importer? Im interested to see how it all goes for you. Good luck

 

[Scott]

29/24mm Valves..

Should be 15hp easy, from what Ive seen people do and to what extent already i would be pretty dissapointed if it was anything under 16hp. this is just not a slap it together motor Mack, I wouldnt spend all this cash on custom made parts just to slap em on and hope for the best.

 

[Sidney]

When do you expect this project will be finished?

I'd love to see it running.

 

[Scott]

2ish months, It Depends on My cash. As Soon as I Send the money The Build will be complete in a Month tops. It Just depends on when I Have the money to send . I may end up going with the 59mm Piston, as Advised by the machinist, as he reckons there isn't much performance difference from the 59 to the 60 and the 59 is safer.

 

[Mack]

Bumpty Bump...