up to using 550 pistons

[Johnwebley]

I know its winter,and we can't get out on the sohc,so an idle mind starts to wonder1

  if I ever wanted to rebuild the top end of my 500,and it needed a rebore and pistons,could I use  the original 550 std size pistons ?

 they are 58.5 mm dia,use the same stroke,use the 550 gasket set,and still have 2 over sizes to go,

  any reason why not ??

  and for future reference,what size should they be bored to ?  58.55 ?? or is that to tight ?


http://www.ebay.co.uk/itm/74-78-HONDA-CB550K-STANDARD-SIZE-PISTONS-SET-4-PISTONS-INCLUDE-10-CB550KPS-/262643526993?hash=item3d26c62d51

[Trigger]

You rebore to the piston size and why would you want to fit 550 pistons ? Then you will have to up the jets.

[hairygit]

You would probably need to use 550 barrels and have crankcase mouths bored to accept them, which is a full stripdown. The 500 barrels MIGHT be able to take 550 bore, but it would leave the liner so thin, it would be risky.

[Trigger]

It is rare for a 500 to need a rebore John but, if it does need, use these >>http://www.ebay.co.uk/itm/HONDA-CB500K-CB500F-0-5mm-56-5mm-Oversize-Pistons-Set-4-Pistons-included-CB500PS-/252159005869?hash=item3ab5d914ad:m:mVeOMf_ufOFE836bq389_kw

[Johnwebley]

It is rare for a 500 to need a rebore John but, if it does need, use these >>http://www.ebay.co.uk/itm/HONDA-CB500K-CB500F-0-5mm-56-5mm-Oversize-Pistons-Set-4-Pistons-included-CB500PS-/252159005869?hash=item3ab5d914ad:m:mVeOMf_ufOFE836bq389_kw

  I had to strip down and replace 1 piston,and 4 sets of rings,as the rings had broken,back about 10k miles ago,the bores had no wear
ridge,and were still very tight,

 the question was just idle musing !!

 you know,idle brain makes mischief !!!


 but thanks for info and replies

[Bryanj]

Std 550 are 12th oversize 500 ones (+3.0mm) and the bores can be done but expect to pay more for 550 than 500 and the rebore will be dearer due to number of passes of bar

[matthewmosse]

I think someone I know had a cb550 he'd fitted with cb500 cases(, and clutch etc presumably) and I belive he said he'd relived the crank case mouths to accept the cb550 barrels. I cannot recall the details exactly I was just glad to be shot of a set of cb550 crank cases in exchange for someone welding my mums car. I think if my cb500 needed a rebore I would be scrounging the spares in my shed for either a cb550 set of barrells etc or 650 rather than go for a rebore. Thinking about it in my long term / mothballed projects pile is a cb500 bottom end, loosely fitted with a cb650 sohc top end. Well burried amoungst 10 other sohc 500 and 550 motors.

[Colonial-Clive (yindi)]

You could always go for a big bore kit 600cc cost approx £120 and £60 to rebore!

[Bryanj]

Where  do you get a £50 rebore, all round here want £25 per hole and for the 600 kit it's more as you have to bore the block for  the liners then the liners for the pistons so more like £60 per hole with removing liners

[Colonial-Clive (yindi)]

Put big bore 600 kit in my 500 no problems and yes the more you bore the more you pay.

[florence]

but does all this modification have much effect on insurance premiums?

[Colonial-Clive (yindi)]

Just got mine quoted £74 with 600 kit and loads of other mods so not to bad

[matthewmosse]

No difference to my insurance for bunging a cb550 engine in instead of 500. I'm in the habbit of swapping engines out if they give any issues thanks to having netted a few when they were a bit cheaper.