Het Scooter Forum by Scooterforum.net - View Single Post - Port timings Metrakit pro race..MINA. 47.6

DRXRACING · 17-01-2008, 03:32

Okay guys just left the degree wheel on a 39.2 stroke mina engine with a 47.6 metra kit pro race cylinder. The findings were pretty lame. IMO.
With a thin b gasket < 0.19mm

XO 85 atdc
TO 122.5 atdc
XD 188 degrees
TD 113 degrees
BD 37.5degrees

With 1.11 mm of base gasket

XO 83 atdc
TO 119 atdc
XD 193 degrees
TD 121 degrees.
BD 36 degrees

Of course I would have to machine the head/cylinder to tighten up the squish.
My question is this, Is this timing close to the pro race timings or is this a SP cylinder being passed off as a PRO RACE cylinder kit. Both are new and are from the US Metra kit distributer.
I'm thinking the cylinder should be timed at 195 exhaust and 129 to 132 transfer.

What do you think?
Since the main transfer is so close to the sub exhaust port I fear raising it to get the 129 to 132 timing. But raise the secondary and boost port.
Thanks in advance.

17-01-2008, 03:32	#1 (permalink)
DRXRACING Registered User	Port timings Metrakit pro race..MINA. 47.6 Okay guys just left the degree wheel on a 39.2 stroke mina engine with a 47.6 metra kit pro race cylinder. The findings were pretty lame. IMO. With a thin b gasket < 0.19mm XO 85 atdc TO 122.5 atdc XD 188 degrees TD 113 degrees BD 37.5degrees With 1.11 mm of base gasket XO 83 atdc TO 119 atdc XD 193 degrees TD 121 degrees. BD 36 degrees Of course I would have to machine the head/cylinder to tighten up the squish. My question is this, Is this timing close to the pro race timings or is this a SP cylinder being passed off as a PRO RACE cylinder kit. Both are new and are from the US Metra kit distributer. I'm thinking the cylinder should be timed at 195 exhaust and 129 to 132 transfer. What do you think? Since the main transfer is so close to the sub exhaust port I fear raising it to get the 129 to 132 timing. But raise the secondary and boost port. Thanks in advance.