Basic tuning info please

[nickw]

Need reminding please. Have stripped and rebuilt a well tuned Mugello and now putting back together. Where is it best to have top of piston when at BDC? Exhaust port or transfer port? Also I've kept base plate from original build and it is for a 225cc whereas barrel is 200cc reed valve. Would this effect it greatly (I didn't build engine originally) This base plate puts the piston top level with exhaust port and just over bottom of transfer. So if I put 2 gaskets on it puts transfer level with piston top. Cheers

[bazza3004]

Base packer wont make any difference regarding it being for a 200 or a 225 as the barrel spigot outer diameter is the same. What is the squish with just the base packer fitted. Once you find this out you can see where you need to go regarding adding a gasket (or not).

[dscscotty]

There is no easy answer to your question, to work it out correctly you would need to know the port tings required for the tune on cylinder, it will run, however the characteristics and power delivery will be considerably affected by the heights of the port and where you set them, do you not have any info on who tuned the cylinder?

[nickw]

Cheers Bazza3004.
Scotty sent you pm don't want to put on here who tuned it, cheers. I thought port timings would come into it. That's me completely scuppered then