Topic: WTB: Honda CB750 K8 Pistons

[jkbarberie]

Set of first over pistons and rings for a 1978 Honda CB750 K.  An 836 big bore kit would be okay too.

Thanks,
Jeff

[madmtnmotors]

CycleX for 2nd or 4th over:

http://www.cyclexchange.net/Engine%20Parts%20Page%20(Non-Cafe).htm


Ebay for 836:

http://www.ebay.com/itm/Honda-CB750-750K-SOHC-1969-1978-836cc-65mm-Big-Bore-Pistons-Kit-w-Head-Gasket-/111765051447?vxp=mtr


Both of the piston kits above are flat top pistons. The dome on the K8 750 pistons are so small that these flat tops work fine. You will recover some of the compression loss as a result of the compression gain due to the overbore (you'll be compressing a larger volume into the same combustion chamber). I just used a set of 4th over pistons from CycleX in my recent K8 build (project "Evolution" linked in my signature) with excellent results. 4th over will bump displacement from 736cc to 761cc.

This might do better in the "Parts Wanted" section if you are looking for 2nd hand parts, unless you are looking for suggestions about new items like I've referenced above...

[jkbarberie]

Thanks for the information.  I was wondering if anyone out there has purchased the $120 big bore kit?  The price seems ridiculously low and makes me wonder about quality.

BTW I enjoyed reading the Evolution thread!

Jeff

[madmtnmotors]

I was wondering if anyone out there has purchased the $120 big bore kit?

There's a fifteen page thread devoted to them:

http://forums.sohc4.net/index.php/topic,89779.0.html

Overall consensus seems pretty positive. I Have a set but have not installed them yet.

BTW I enjoyed reading the Evolution thread!

LOL

The more I worked on it, the comedy of errors kept growing. The 500 mile break in and service is complete. No leaks and it's running great. Working on putting the miles down towards the first regular oil change at 1500-2000 mi. The miles would rack up more quickly if it wasn't still so freakin hot here! We're still in the mid 90's with afternoon monsoons...

[Restoration Fan]

The more I worked on it, the comedy of errors kept growing. The 500 mile break in and service is complete. No leaks and it's running great. Working on putting the miles down towards the first regular oil change at 1500-2000 mi. The miles would rack up more quickly if it wasn't still so freakin hot here! We're still in the mid 90's with afternoon monsoons...

Wilbur,
Are you going to Valdosta in November?