Crankcase transfer ports too large

[Mr Dave B]

Hello folks.
Please can someone help.
Will a standard SIL stage 4 200cc barrel, piston and head work on crankcase that has had the transfer ports opened for a 225 TS1 barrel.

Will I need to open the barrel spigot and blend the barrel base transfer area to the crankcase.

Thanks lads.

[hullygully]

wouldn't harm it too bull nose them in the barrel

[Adam_Winstone]

You can do but I have a suspicion that it'll make no difference, as per Darrell Taylor's 'waste of time and effort' feature in Scootering.

[Knowledge]

I agree Adam.

At the bottom of the transfers the fresh charge has little velocity from the pumping action of the primary compression ratio. It is only when the mixture is actually in the transfer ducts that it obtains some speed and, as importantly, some direction.

In a tuned engine, when things really need to get going, the negative pressure phase of the expansion will do more work than the primary compression anyway and will suck the fresh charge up the transfers regardless of minor obstructions at the base of the barrel.

So don’t worry Dave B.

[Mr Dave B]

Thank you for your help chaps. Very much appreciated.