VMC G 177

[scuffa]

What are people’s preferences between using 20mm or 24mm on this type of kit? Thanks

[adrian]

I have a vmc 177 aluminium barrel kit, and I'm using a 28, but also long stroke and fully ported

[gpowell]

Adrian has stepped it up a gear there.

If using the SI, if you have a 20 use it with some upjetting on the main and possible the pilot.

[scuffa]

I have both SI versions. I guess the 20 will give less top end but more drivability?

[gpowell]

Id go 20mm first

[gpowell]

Last oe i did was a Px125 standard crank, DR177, SI 20/20, drilled filter and Sito plus exhaust. Standard gearing and clutch

45/140 idle
160/BE3/112

Ran well

[scuffa]

I'm going to run a 57mm Mazz race crank, 22 clutch, drilled filter and SIP 3. Standard 125 casings, but I'm thinking of opening the inlet. Keeping autolube. Don't know what the jetting would be for that?

[adrian]

As you are changing the crank, you should consider opening the ports on the barrel and matching the ports on the cases 😁

[adrian]

And when you have ported the motor , you can buy my polini 30mm carburetor and jets 🤣

[gpowell]

Feb 19, 2024 8:17:50 GMT scuffa said:

I'm going to run a 57mm Mazz race crank, 22 clutch, drilled filter and SIP 3. Standard 125 casings, but I'm thinking of opening the inlet. Keeping autolube. Don't know what the jetting would be for that?

Thats a reasonable mid range move. I would be inclined to blend and match the barrel to casing and carb and box to the casings.

[scuffa]

I’ve fitted the 57mm Maz crank and cylinder. The problem is I can’t get the squish below 1.7mm (1.4mm +/- 0.1) and that’s with no base gasket. The piston doesn’t reach the bottom of the transfers either. Are these kits best suited to a 60mm crank? 🙁

[gpowell]

Im not familiar with this kit, but a quick look on SIP states 57mm stroke.

I would assembly with the sealant on base and not worry too much about squish, get it ran in and see what happens,