minarelli vertical cylinders on puch derbi etc

Didn't see much info on here about this besides "same stud pattern!!", so I'm putting it in writing for the people. Did it for derbi but could be useful for Puch or anything similar.

I've been getting my derbi pp back together after dumb frame issues, and got super curious about 43mm stroker Minarelli vertical kits. There's 2 versions of these kits, 80mm and 85mm conrods.

Find the kits here : https://www.rrd-preparation.com/en/388-kit-75-85cc-race-long-minarelli-vertical-booster-bws-

I got the Athena 43mm stroke, 85mm rod.

So in my head i was like ok i have a 43mm stroke and 90mm conrod, I'll get the 85mm kit and make a spacer and live a happy life. Wrong. Turns out the deck height on the Minarelli cases is much lower, so my kit was about 1.5mm too high. Usually, I'd give up on the kit at this point but i had some very nice people (thanks Dave 🙃 ) help me machine the base of the cylinder 1.5mm, getting the port timings and squish right where i wanted them.

Anyway, the stud spacing is a little bigger than Puch, a lil smaller than derbi. Drill the stud holes out like 2mm in diameter bigger and you'll fit on either one. Case matching is a breeze on derbi, so much material on the front. I alumiwelded the back as a precaution, and I'm glad i did because I blew threw a bunch at the top. On puch, you won't be able to run it without adding material to the front, and to the back if you're going for the deep match.

Here's the cases close to matched.

IMG_20210719_201818.jpg

I've seen people like jbot run an AC head with scooter kits just fine, but it didn't get me around the block with comfortable temps even with the biggest head i had laying around. I ended up using a treats LC/AC head with awesome temps. Rode around, ripped up some SF hills WOT and barely passed 180°. Bike is fast, life is happy.

shout out Polini x1 radiators on eBay which are going for cheap and are a good alternative to those bulky dirt bike radiators.

Glamour shot + quick rundown

IMG_20211003_161618.jpg

-Athena 47.6mm Minarelli Vertical Stroker

-treats Athena lc/ac head

-Tm24

-Voca Derbi V-Protos exhaust

-HPI mini rotor

-Hobbit Xtreme bell

Mmm that's it

Re: minarelli vertical cylinders on puch derbi etc

Well that’s awesome. Glad that the watercooled head worked out. I wonder how much a machine shop would charge for such a job?

Re: minarelli vertical cylinders on puch derbi etc

Dirty30 Dillon /

Curious after all this work, why not just roll with a full LC cylinder for Minarelli Horizontal?

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

Well it's a piston port, so the intake is on the cylinder. You could do a Minarelli horizontal just as "easily" on a pyramid reed, though the stud pattern is waaay off.

Oh and they don't make full LC vertical cylinders :(

There is a single one from Italy that's way too much money and it's not even made for a stroker crank lol (edited)

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

> Buttcheeks BUZZARD wrote:

> -------------------------------------------------------

> Well that’s awesome. Glad that the watercooled head worked out. I wonder

> how much a machine shop would charge for such a job?

Probably wouldn't be worth it to do it at a machine shop. But if I'd do it again, I'd go for the 80mm rod kits. Not the 85mm ones. That way you'll actually need to make a base spacer without needing to machine the cylinder to bring the base down. Much easier to make a base spacer than machine the cylinder I'd say. (edited)

Re: minarelli vertical cylinders on puch derbi etc

Totally normal JBOT /

I realized that I had that scooter kit awfully detuned with that eurokit head (low timing, low rpm hitting pipe) My timing was awfully low. I ended up bringing timing back up to where it was making great power and temps got a bunch higher. I also have to chop the pipe to get my rpms up.

So yeah I probably will water cool it once I get it tuned right.

Scooter kits are fun, just gotta fuck with the bottom of the cyl

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

Yeah i think i might have some room to squeeze out some power. Whats the temp situation on water cooled heads? Keep it under 230 ish? 260 max? Never done water cooled before.

Re: minarelli vertical cylinders on puch derbi etc

Totally normal JBOT /

Well fully loaded with my pinball hobbit

(80lbs of extra gear) in the 60s I ran like 250-260 max head temp.

Usually riding local and at speed with a normal less heavy setup I like to keep cht below 200.

It really all depends on your timing and compression. I run lowish compression for easy wicking. Like 130psi. Engine wants to spin by itself

Re: minarelli vertical cylinders on puch derbi etc

What is the issue with a LC setup if temps get to where an AC setup normally runs. My AC setup is 325 to 350 in optimal range. Would that cause the LC parts to blow out from too much added pressure from the heat?

Re: minarelli vertical cylinders on puch derbi etc

Totally normal JBOT /

Funny you should ask.

If you get a full jacketed water cooled cyl and head to those temps you could seize. Usually the cyl is much cooler than the head, but if they are both cooled by the same water the cyl is artificially raised and cannot wick the heat away. My solo is having that issue, I’m running at like 325-350 and it wants to stick. I need to add a radiator to get those temps down.

Now if you’re running a wc head alone yeah you can get temps into the 300s but you start to get into a weird place. It starts to get really easy to boil over and the you’re tuned hot there’s no buffer.

You could quickly burn it up.

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

Took it on a longer (for SF standards) ride today...very exciting. Like 4 miles WOT, didn't pass 180 degrees. Got a proper scooter pipe coming in soon, powers gonna be wacky

Screenshot_20211006-212832.jpg

(edited)

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

Oh and I'm running jialing clutches. They're super cheap on AliExpress and I've been running the pads on derbi hubs for hundreds of miles with no issues. Easy alternative for replacing derbi and hobbit clutch arms.

Screenshot_20211006-214523.jpg

Re: minarelli vertical cylinders on puch derbi etc

Totally normal JBOT /

What’s the cost with shipping on the clutch?

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

I got 2 sets for 35 shipped. Took about 3 weeks to receive. Just ordered another set to have as backups.

Re: minarelli vertical cylinders on puch derbi etc

Wtf, secret AliExpress derbi tech?!

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

Yup. I've been running them low stall for a while on my gila pp build. Running them with high stall on this scoot cylinder build and they rip, but we'll see how reliable they are in the long run. Cheap enough to have some backups around though. The stock derbi and hobbit ones are already hard enough to find in good condition, much less for cheap. (edited)

Re: minarelli vertical cylinders on puch derbi etc

Pussy Licker420 /

The vertical cylinder porting is a mess! That third transfer probably hurt you, I would tryed without.

Are u running a stock intake? They sell some pretty large plenum intakes

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

> Tweaker trash wrote:

> -------------------------------------------------------

> The vertical cylinder porting is a mess! That third transfer probably

> hurt you, I would tryed without.

>

> Are u running a stock intake? They sell some pretty large plenum intakes

Gila reeds with an MLM tomos 24mm intake with some janky reed adapter tech™. What are the problems with the porting?? Why would the 3rd transfer hurt me?

Re: minarelli vertical cylinders on puch derbi etc

Pussy Licker420 /

> Jose Castanon wrote:

> -------------------------------------------------------

> > Tweaker trash wrote:

>

> > -------------------------------------------------------

>

> > The vertical cylinder porting is a mess! That third transfer probably

>

> > hurt you, I would tryed without.

>

> >

>

> > Are u running a stock intake? They sell some pretty large plenum

> intakes

>

> Gila reeds with an MLM tomos 24mm intake with some janky reed adapter

> tech™. What are the problems with the porting?? Why would the 3rd

> transfer hurt me?

I’m not saying it is but the porting is so odd with the reeds

Re: minarelli vertical cylinders on puch derbi etc

I'm setting one up on a v1, haven't figured out how I'm going to port it down for the lower stroke. This is a 40 stroke kit. I'm sure it would run fine like that but it's not right obviously.

The exhaust port is easy to cut down, I am looking at buying a 1/8in angle tool one I have had my eye on to cut down the transfers.

IMG_20211010_154721.jpg

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

> Graham Motzing wrote:

> -------------------------------------------------------

> I'm setting one up on a v1, haven't figured out how I'm going to port it

> down for the lower stroke. This is a 40 stroke kit. I'm sure it would

> run fine like that but it's not right obviously.

>

> The exhaust port is easy to cut down, I am looking at buying a 1/8in

> angle tool one I have had my eye on to cut down the transfers.

> >

Oh interesting. I didn't go the short stroke cylinder way because I was worried the port timing would be way off with the 43 stroke on derbi. Is it not super high? Are you running a spacer under it?

Re: minarelli vertical cylinders on puch derbi etc

> Tweaker trash wrote:

> -------------------------------------------------------

> > Jose Castanon wrote:

>

> > -------------------------------------------------------

>

> > > Tweaker trash wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > The vertical cylinder porting is a mess! That third transfer

> probably

>

> >

>

> > > hurt you, I would tryed without.

>

> >

>

> > >

>

> >

>

> > > Are u running a stock intake? They sell some pretty large plenum

>

> > intakes

>

> >

>

> > Gila reeds with an MLM tomos 24mm intake with some janky reed adapter

>

> > tech™. What are the problems with the porting?? Why would the 3rd

>

> > transfer hurt me?

>

> I’m not saying it is but the porting is so odd with the reeds

you literally just said that 3rd transfer was hurting him

Re: minarelli vertical cylinders on puch derbi etc

Dirty30 Dillon /

Yeah, the third transfer is not "hurting" anything, but the general shape and consistency of the port/match work is probably not doing you any favors for eddying.

What's the weird chasm in the Top Left of the third transfer?

Re: minarelli vertical cylinders on puch derbi etc

Yeah dos cycles has a pile of these cylinders laying around so I got this one cheap, didn't know they have long stroke, 12 pin versions, next time I'll go that way.

Yeah I am making a spacer for the v1 to fit this kit more details soon.

Re: minarelli vertical cylinders on puch derbi etc

🇮🇹💦 Of the Loin /

I thought it was okay to have the piston be below the ports at BDC ?

Jbot told me what that did to the performance but I have since forgotten

Re: minarelli vertical cylinders on puch derbi etc

> 🇮🇹💦 Of the Loin wrote:

> -------------------------------------------------------

> I thought it was okay to have the piston be below the ports at BDC ?

>

> Jbot told me what that did to the performance but I have since forgotten

nah maitland, it’s the either way around. piston below the ports is not good

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

> Graham Motzing wrote:

> -------------------------------------------------------

> Yeah dos cycles has a pile of these cylinders laying around so I got

> this one cheap, didn't know they have long stroke, 12 pin versions, next

> time I'll go that way.

>

> Yeah I am making a spacer for the v1 to fit this kit more details soon.

Yeah the long rod kit was my mistake. The reason I had to mill down the base of the cylinder was because the piston went way below the ports, the exhaust port timing was too high for what i wanted, and my squish was too high. But if you're making a spacer you should be able to fix that by not making it as tall, right? Or is the piston too high at tdc? (edited)

Re: minarelli vertical cylinders on puch derbi etc

Jose Castanon /

> Dirty30 Dillon wrote:

> -------------------------------------------------------

> Yeah, the third transfer is not "hurting" anything, but the general

> shape and consistency of the port/match work is probably not doing you

> any favors for eddying.

>

> What's the weird chasm in the Top Left of the third transfer?

Piston port cases have the third transfer cast in, but blocked off. to match it, i cut down the little wall, but the transfer on the cylinder isn't as tall as the cases, so there's a little lip with a bunch of extra space on the cases.

pp.PNG

not ideal but it looked a lot better in person once it was done lol.

Re: minarelli vertical cylinders on puch derbi etc

Pussy Licker420 /

> Jose Castanon wrote:

> -------------------------------------------------------

> > Dirty30 Dillon wrote:

>

> > -------------------------------------------------------

>

> > Yeah, the third transfer is not "hurting" anything, but the general

>

> > shape and consistency of the port/match work is probably not doing you

>

> > any favors for eddying.

>

> >

>

> > What's the weird chasm in the Top Left of the third transfer?

>

> Piston port cases have the third transfer cast in, but blocked off. to

> match it, i cut down the little wall, but the transfer on the cylinder

> isn't as tall as the cases, so there's a little lip with a bunch of

> extra space on the cases.

>

> not ideal but it looked a lot better in person once it was done lol.

That’s mad chill

Re: minarelli vertical cylinders on puch derbi etc

I mean it's not ideal but it's not like the thing is gonna explode or not run. Just giving up a lot of power.

I just emailed my tool guy and got the grinder on order. Yeah with the short stroke I can't have the piston sticking out 2mm at TDC so gotta port it down.

> LSLB RXb wrote:

> -------------------------------------------------------

> > 🇮🇹💦 Of the Loin wrote:

>

> > -------------------------------------------------------

>

> > I thought it was okay to have the piston be below the ports at BDC ?

>

> >

>

> > Jbot told me what that did to the performance but I have since

> forgotten

>

> nah maitland, it’s the either way around. piston below the ports is not

> good

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