Scooterotica

If my understanding of the 2 stroke cycle is correct then at bottom dead centre the transfer of the fresh charge from under the piston into the barrel should be complete so there should be no pressure to blow through the boost port to create spit back.
BUT in the real world I consider this to be a bad design especially for a £400 kit!
Can you not ask for your money back as it is "not fit for use"

CPH Lambretta wrote:@ 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.

Measure from base gasket face to head gasket face. Std will (or should) be 100mm, 60mm variety will (or should) be 103mm.

Also, with the amount of hassle I've had with my Mugello..I'll never buy another..

which version muggy is that you have the hassle with Ghost?

Donnie wrote:which version muggy is that you have the hassle with Ghost?

V4 small block..

I was wondering about contacting Tino and asking if it was designed that way i.e that the piston is well below the exhaust and transfer ports at BDC and that the boost port window inthe piston shows in the inlet.
To me it looks like the barrel is the right height but all the ports are at the wrong heights.

If you can see the hole at BDC some of the charge will have already spat back into the carb just beforehand. We had one on the dyno recently that you could taste fuel in your tea afterwards there was that much fuel flowing out of the carb.
If you drop the barrel you will more than likely be ok.

red ghost wrote:

Donnie wrote:which version muggy is that you have the hassle with Ghost?

V4 small block..

Hmmmm good to know, ive still got a V2 that Ive never had a bother with, think if I ever do need to get another topend ill be avoiding the later muggys by the sounds of things :-/

:bald:

Its on an Italian gp 150 block

CPH Lambretta wrote:I was wondering about contacting Tino and asking if it was designed that way i.e that the piston is well below the exhaust and transfer ports at BDC and that the boost port window inthe piston shows in the inlet.
To me it looks like the barrel is the right height but all the ports are at the wrong heights.

I've had the same (but opposite) with a Mugello where the cylinder was the right height but the transfers and exhaust were obscured at BDC but with timing of 114 and 180 respectively. Thicker base gaskets brought the transfers up to a sensible duration but left the exhaust way too peaky.

It's worth checking the timing "as is", and then working out options based on that.