650 jug max overbore

[Mr.Blue]

whats the max overbore for 650 jugs? 850 pistons a possibility (7mm overbore)?


info: bike is a 550 so it would be a 650 top conversion but if i have it apart....

[TeamDar]

With the stock sleeves most Suzuki's can go 3mm over. Some can go more, but not 7mm.

[brveagle]

7mm is out of the question.

I bored out my 650 block 3mm to increase displacement to 740cc's, but ran into cooling issues. The motor liked to run very hot! It was my daily rider, so i opted to go back to the 673cc size.

good luck

[trippivot]

don't believe the heat hype.

sleeve wall thickness should be no less than 0.080" - you can go big without many issues.

cooling issues can be fixed with
#1 richer jetting
#2 colder heat range spark plug
#3 retarded ignition timing
#4 a small electric fan for backed up stop and stop traffic
#5 header insulation wraping tape