Using Minarelli Horizontal Cylinder

Cannonball3

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Hello everyone,
First post here but have been on the other forum for years, so am pretty familiar with MB building.
Just got into the Minarelli thing, building a vertical hybrid. Since the horizontal cylinder kits are so cheap ($39) shipped I bought
one to experiment with. From reading on other forums the Minarelli builders seem to prefer the horizontal engine as it breathes better with
the bigger reeds.
So it seems the H engine is on a 50 mm stud spacing, which I believe is the same as a YD100. One could easily make a case reed engine from one of these cylinders, a proper spacer plate, and a G2 reed assembly, and a bit of work of course. It would be a 70cc but these
engines make some pretty good HP when properly modded, so I dont think the 10cc loss of displacement is a deal breaker as the porting on the Minarelli cylinder is so superior.

Thoughts?
 

mark20

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Welcome to the forum!

A case reeds biggest problem on these engines is that there basically no room to work, So the intake is limited by the size of the engines case. (ie, you gonna have to run smaller reeds then what a vertical can)

Should also note that the yd100 has a different spacing then the regular 66cc motors. (Sometimes advertised as 80, but there only 66cc in reality)

The minarelli's make good power, if ported correctly, as well as the bottom end matched (you gonna need to make a 3rd transfer port for the case reed)
 

Cannonball3

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Thanks for the reply.

I have a YD100 and it measures 50mm on the spacing as does the Minarelli horizontal.so in theory it should “bolt on).
There are many case reed conversions using the G2 reed case, looks reasonably easy. The G2 reeds are fairly large, look similar to the H Minarellis in size. What Im not sure about is the YDs geometry. Needs to be a 40mm long rod engine. I have been running the YD for a few years and it is my favorite engine. Hate to disturb it. I will buy another
engine only if it meets the specs. Main idea is to convert to use the cheap 70cc horizontal cylinder kits, as well as the cheap G2 reed blocks. They can be easily modded to use the VM20 carb.

Just throwing this out there to see if Im missing anything in my thinking before I get parts on the way.
 

khodge9

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Only problem with the yd case is there is about half the room to work with for case reed as opposed to the 66cc case be really hard to fit in there. Already thought about it
 

Cannonball3

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I honestly never went far with it, so cant say anything other than the G2 reed “ looked” like it could be made to work.
Also one would have to fab their own spacer, not too bad to do. Im satisfied with the 2 vertical builds I now have.
Its too bad, the horizontal cylinder set is so cheap and plentiful.
 
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