GS750 compression increase options?

[oldryder]

REbuilding top end of 77 GS750. when complete it will have stock compression 850 kit, Mac 4 into 1, and K&N in stock airbox. Stock cams. Head and jugs are going to machine shop for valve job and boring.

Should I also be considering machine work to increase compression and if yes what machine work is recommended. (Considered hi compression 850 kit but it was 13:1 and I thought that was too high for street.) Bike will be ridden on the street, not raced but I figure as long as the machinist has the parts . . . .

Thx in advance for any help. Mark in MN

[AOD]

Wow...13:1 is REALLY high for an air-cooled engine. Unless you have serious race fuel you'll be detonating all day long.

You need to find a way to lower that some...I'd say anything over 10.5:1 might be trouble with 93 octane and an air cooled engine.

~Adam

[rckrzy1]

Wow...13:1 is REALLY high for an air-cooled engine. Unless you have serious race fuel you'll be detonating all day long.

You need to find a way to lower that some...I'd say anything over 10.5:1 might be trouble with 93 octane and an air cooled engine.

~Adam

Unless this is modded for alcohol ??

[oldryder]

Guys; The engine with the bore kit I ended up buying will be Stock compression; I passed on the high compression bore kit. Looking for options to raise the stock compression a bit.