What exhaust to malossi big bore 86cc

[Nick L Møller]

Eatmydust: What crank can i use for the 86cc big bore on mineralli???? It will be LOT cheper is i can use another crank for the malossi that cost alot of money

So what crank can i use??

 

[BartR.]

I think there is no crank that has a 17mm small-end and a stroke that comes near to 44mm. So, you can buy for example a cheap Kiesler 2fast crank, and replace the conrod for a conrad 85mm and 17mm small-end. Ore just resize your small-end to 17mm. This is no big deal for any proffesional metal adaptation company.

Finding a conrod with 17mm small-end, and futher more the same specifications as the Malossi 86cc conrod is also no big-deal ( don't know this for sure, but i'm convinced it's possible )

 

[Nick L Møller]

BartR: So if i buy a Kiesler 2fast4race crank is that Rod80 or 85?? And it is 44 mm right like Big bore??

And if i buy that kiesler 2f4r crank and get it up to small-end to 17mm.

Is that all??? or??

 

[50cczip racer]

cant u just use the 50mm 12mm pin am6 derbi piston instead and use any crank

 

[Nick L Møller]

Marco from xsh says no

 

[BartR.]

No, the 12mm piston is shorter then the 13mm.

And yes, Kiesler has built a crank that's equal to the 2fast crank. So, milling up the small-end to 17mm is al you have to do. But this has te be done very carefull.

 

[Nick L Møller]

If i Buy that Kiesler 2f4r crank. The only think is to tuned the crank op to 17mm so??

 

[50cczip racer]

if the piston is shorter then use no base gasket or skim the cylinder base
? by how much is it shorter

 

[EatMyDust]

I think there is no crank that has a 17mm small-end and a stroke that comes near to 44mm.

You think wrong! Ok, a friend of mine have bought a few days ago a brand new 2fast crank, here's a pic:



As you can see, this crank has the same small end bearing that comes with the Stage 6 R/T 12mm cranks(80,85,90mm rod, whatever) , and that's for 17mm bore.

 

[Browni]

if the piston is shorter then use no base gasket or skim the cylinder base
? by how much is it shorter

Not this is the problem. The AM 50 mm piston has a short skirt. If you use it for a longer stroke, the piston doesn't cover the botton of the exhaust port at TDC, so the exhaust channel is connected to the crankcase!

 

[Browni]

You think wrong! Ok, a friend of mine have bought a few days ago a brand new 2fast crank, here's a pic:



As you can see, this crank has the same small end bearing that comes with the Stage 6 R/T 12mm cranks(80,85,90mm rod, whatever) , and that's for 17mm bore.

Yes the 2fast Minarelli has a 17 mm bore!

Wow what an upgrade, the 2fast crank has a box! Few years ago I've got the crank and cylinder in a big box filled with little sponges.

 

[BartR.]

@Browni, that's what i ment. It's about 4mm shorter.

@ eatmy....: If your right, than this will also be a solution.

 

[Nick L Møller]

So what can i do so?? hehe

 

[apriliafan]

if some1 want to be one of the first,having the mhr big bore 86,5ccm and crank(cyl for 400 euro and crank for 625euro) can contact me XD

 

[luis_algarvio]

You think wrong! Ok, a friend of mine have bought a few days ago a brand new 2fast crank, here's a pic:



As you can see, this crank has the same small end bearing that comes with the Stage 6 R/T 12mm cranks(80,85,90mm rod, whatever) , and that's for 17mm bore.

Yes i confirm. EMD its rite here some pics i just got:





So as the cylinder kit comes with the 13mm pin small bearing it's all fine :L

 

[Nick L Møller]

So i can use a 2Fast4race crank???

 

[Tommy]

Yes, every crank with a 17mm small end and 44mm stroke. Is 2fast, simonini etc.

 

[Joël]

Yes the 2fast Minarelli has a 17 mm bore!

Wow what an upgrade, the 2fast crank has a box! Few years ago I've got the crank and cylinder in a big box filled with little sponges.

Also the piaggio has a 17mm bore.. That is, in my case.

It's a bit strange but that means the conrods have 15,16 and 17 mm bores...

 

[Nick L Møller]

Hmm What about Kiesler 2Fast4Race crank can i use that one?? That is a chep one

 

[Tommy]

Hmm What about Kiesler 2Fast4Race crank can i use that one?? That is a chep one

Simonini is almost the same and cost 160 euro. I use this one for almost 2 years on my 2fast engine and it works well