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SOHC.co.uk Forums => CB750 => Topic started by: UK Pete on March 08, 2011, 07:22:43 AM

Title: K1 pistons and rings in a F1
Post by: UK Pete on March 08, 2011, 07:22:43 AM

Does any one know if K1 oistons and rings work in a F1, if so are there any advantages or dissadvantages,
Pete

Title: Re: K1 pistons and rings in a F1
Post by: steff750 on March 08, 2011, 07:34:19 PM

 ::) off the top of my head i would say they would work,as long as they are the same size, a local engineer who has done work for me  would always bore the barrels too match the pistons and not just bore too a specified oversize ,i have mixed and matched k0- k4 bits over the years, i think the only real difference was in the f2 with the bigger chocolate valves, I'm sure some one will put you right soon enough

Title: Re: K1 pistons and rings in a F1
Post by: Bryanj on March 09, 2011, 08:04:02 AM

Not 100% sure but i think you will get a slightly lower compression ratio

Title: Re: K1 pistons and rings in a F1
Post by: kaceyk2 on March 09, 2011, 03:35:09 PM

I cant remember Pete if the F1 had domed pistons the same as the F2, if it did then + one with the slightly lower compression...but it really would be very slightly lower....

Title: Re: K1 pistons and rings in a F1
Post by: Spitfire on March 09, 2011, 07:49:15 PM

The F1 pistons are not as domed as the F2, they are very slightly domed with small cut aways, here's a pic of mine.
(http://i192.photobucket.com/albums/z244/DennisMcc/Engine/Rebuild-15.jpg)

Cheers

Den

Title: Re: K1 pistons and rings in a F1
Post by: AshimotoK0 on March 17, 2011, 07:35:08 PM

There was a change somewhere in the production run of the F1 from flat to domed pistons. I have both types here but they are both stamped '392'. Some Ebay **** sold me barrels and pistons, supposed to be K1 but were F1 before I attended the ChrisR school of CB750 part identification. Shame as they have only done 20K.

cheers

Ash

Title: Re: K1 pistons and rings in a F1
Post by: UK Pete on March 17, 2011, 07:41:14 PM

Hi ash if you are considering selling give me a pm with details as i still do not have a top end for my cafe project
Pete

Title: Re: K1 pistons and rings in a F1
Post by: AshimotoK0 on March 28, 2011, 08:10:46 AM

Hi Pete 

Can you send me a blank text so that I have your number and I will call you re: barrels and pistons

07515121226

Cheers

Ash