Scooterotica

What is the max a stage 4 barrel can be taken out to :fb:

Do you mean bore size or port durations?

Barrel bore

Don't know about a SIL barrel, but I've got an Indian 200 barrel for a three wheeler, where the barrel is cast completely around the stud holes (just like the SR185 barrels.) I reckon you could bore that to well over 80mm before you got a pile of cast iron rings on the floor under the boring machine. Not a lot of point, because beyond 78mm you've broken into the stud holes, and beyond 75mm the spigot has already disappeared completely! Regardless of the barrel, the bottom part of the spigot (around 74mm O/D) seems to be the limiting factor, it's just that a barrel with thicker walls higher up is less likely to warp at bores of 70mm and above. Maybe 71 to 72mm is the absolute limit to keep the spigot attached....

Anyone else got one of these barrels? I'd like to see one, I have an idea......

i have one Dan lol

One more reason to tidy the workshop.....! ;op