Can a Honda CB 750 fit in a big bore case?
For the ultimate power hungry: The Honda Bol d’Or / CB 900 F DOHC crank can made fit into the CB 750 case to deliver 69mm stroke (63mm stock). Combined with stock or big bore: Bearings fit, so much for the good news. Rotor and ignition are swapped on the Bol d’Or crank, so you’d best swap them, too. (Need to put an oil seal on the left side).
How big of a bore does a Honda VFR750 have?
Honda VFR750 pistons can make fit after heavy machining together with CB 1100 rods with larger wrist pins (17mm i/o 15mm). Japauto had a 950SS kit based on the standard block but gave that up for the VX1000 with a special cylinder block in late 1973 (Despite the different figures, both kits had 70mm bore).
What kind of pistons does a big bore Honda CB 900 use?
Yoshimura had kits for 812cc and 823cc. Some manufacturers used modified Honda CB 350 twin pistons. CB 900 DOHC pistons have 64.5mm and can make fit for 823cc but there is not much left for deep valve pockets, unfortunately. CBX six cylinder pistons have 64.5mm for 823cc, and a nice compression height.
How big of a cylinder block do I need for a 836?
Uses stock cylinder block which can be bored up to 65.5mm/850cc. Necessary modifications include boring the block, new pistons/pins/clips and head gasket. Most popular 836 kit today comes from Wiseco, at 10.25 C/R and 12 C/R. 10.25 is highly recommended for milder cams and/or low octane (low 90s) gas.
For the ultimate power hungry: The Honda Bol d’Or / CB 900 F DOHC crank can made fit into the CB 750 case to deliver 69mm stroke (63mm stock). Combined with stock or big bore: Bearings fit, so much for the good news. Rotor and ignition are swapped on the Bol d’Or crank, so you’d best swap them, too. (Need to put an oil seal on the left side).
Honda VFR750 pistons can make fit after heavy machining together with CB 1100 rods with larger wrist pins (17mm i/o 15mm). Japauto had a 950SS kit based on the standard block but gave that up for the VX1000 with a special cylinder block in late 1973 (Despite the different figures, both kits had 70mm bore).
Yoshimura had kits for 812cc and 823cc. Some manufacturers used modified Honda CB 350 twin pistons. CB 900 DOHC pistons have 64.5mm and can make fit for 823cc but there is not much left for deep valve pockets, unfortunately. CBX six cylinder pistons have 64.5mm for 823cc, and a nice compression height.
Uses stock cylinder block which can be bored up to 65.5mm/850cc. Necessary modifications include boring the block, new pistons/pins/clips and head gasket. Most popular 836 kit today comes from Wiseco, at 10.25 C/R and 12 C/R. 10.25 is highly recommended for milder cams and/or low octane (low 90s) gas.