Topic: CB750K2 engine rebuild cyl advice please...

[CB750Fury]

Ciao All,

My name is Carlito, proud owner of a K2 and just joined this forum...

Before disassembly, motor was running good, no smoke, no roughness, had 28K miles, would like to rebuild keeping it as stock as possible (no 836cc kit, etc...)

Not sure if I should have my cylinder honed to 1st & pistons replaced?  (Rings for sure will be replaced)

Here are the measurements I took

                                                      Honda recommended replacement if
Cyl bore top           diam  60.4mm        < 61.1mm
              bottom    diam  60.9mm

Pistons                  diam  61mm           < 60.85mm

Pistons Pin Bore    diam 14.95mm        < 15.08mm

Many Thanks for the help
Cheers
Carlito
 

[martin99]

The only measurement you don't include is ring gap. If that's in spec too, I'd suggest a light hone and you'd be good to go. If you intend to use it a lot though, it may be prudent to give it a first bore and new pistons now while you have it apart, to save having to pull it down after another few thousand. Those figures are pretty close to the wear limits IMO. Now's the time to think about a frame kit too

[CB750Fury]

The only measurement you don't include is ring gap. If that's in spec too, I'd suggest a light hone and you'd be good to go. If you intend to use it a lot though, it may be prudent to give it a first bore and new pistons now while you have it apart, to save having to pull it down after another few thousand. Those figures are pretty close to the wear limits IMO. Now's the time to think about a frame kit too

Thanks for the reply...

Correct I came to the same conclusions as to figures being close to wear limits...
I planned on replacing pistons...
I agree with doing a first bore since all is out, although building a Cafe, I do not intend on heavy use, mainly urban ride arround and maybe occasionally a long ride...

Also would you recommend replacing engine studs ??

Thanks
Carlito

[edwardmorris]

Stronger studs only if you're going 836 or more I think, stock should be fine for first oversize. Get a frame kit from Gordon/ilbikes though, well worth the investment.