Mugello Boost Port Question

[CPH Lambretta]

Just fitting my Mugello 186 V4 and with the piston at BDC I can just see the boost port in the piston coming into view in the inlet port.Its only a fraction of a mm but will it give problems with spit back and lost charge?
With the supplied base gasket and no head gasket (I assume non is needed as non was supplied) the squish is perfect at 1.3mm.
So do I need to get the cylinder sitting lower to block that boost port in the piston or will it be okay?
Cheers Nick

[Diablo]

Its not ok and you need to sort it mate.
You'll end up with loads of spit back out of the carb and it will lose power on the road.
To me it seems a bit daft the way these muggys are because as you say it then causes squish and compresion issues further up the barrel when you adjust it for ports.

[Chris CSPE]

Also check that the boost port is closed off from the inlet at BDC as the gap between the two can be as small as 4.5 Mil.

[CPH Lambretta]

Thanks for the input.
Well I'm well pissed off, seems like what ever I buy at the moment is just expensive shite that doesn't fit as it should and needs a fair bit of work to do the job.
With the piston a BDC it is lower than the bottom of the exhaust and transfer ports , and the boost port window is visible in the inlet.
It really looks like the barrel ports are at the wrong heights , they should all be lower, then they would be level with the piston crown and the boost port window in the piston wouldn't be a problem.
I might try leaving out the base gasket (that will get me .3mm lower) and fitting a head gasket, but thats not great because the head should be recessed into the barrel.
Or the other option is getting 1mm off the bottom of the barrel
I really thought for £400 it would just fit
And thats without even going on about the exhaust port being wrong

[Chris CSPE]

Is it a standard size crank (58x107),
Where does the piston come to at TDC,if you do machine the bottom of the barrel at least it can be moved up or down with packers to get the port timings where you want them.

[CPH Lambretta]

Yes it is a standard 58/107 crank.
With a .3mm base gasket and no head gasket the squish is 1.3mm.
The head is slightly recessed ,by about 0.5mm-1mm maybe so it fits slightly into the barrel. This wouldn't be possible if a head gasket was used.

[Diablo]

I'm not sure if .3mm will be enough. I would be more tempted to measure exactly where the piston is at BDC then see what the distance is to the base of the transfers and get that machined of the base.
You'd need to check port timings etc as well.

[red ghost]

Is it a kit for a standard crank or a kit for a 60mm crank?

[CPH Lambretta]

Well I just spoke to camblamb and mike phoenix and they both said its supposed to be like that and the boost port window should show in the inlet at bdc

[CPH Lambretta]

@ Red Ghost I don't know what the difference would be apart from some head gaskets.The box says 64mm/186cc and the piston is a 64mm with a 39mm compression height.
I just checked how much the boost port window shows a BDC and I can get a 0.5mm feeler gauge in but no more.