Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: stevush on April 19, 2016, 11:44:04 AM

Title: Piston ring end gap
Post by: stevush on April 19, 2016, 11:44:04 AM

Can anyone enlighten me as to the end gaps for each of the three piston rings in the bore please ?
Its a new rebore +.5, new pistons and rings. I've looked at the top ring in the bore and it looks to be about 9thou, how does that sound ?
I'd assume the gap should be the same for the second ring, I think the oil control ring should be a little bigger ?

Thanks
Steve

Title: Re: Piston ring end gap
Post by: Chris400F on April 19, 2016, 03:26:29 PM

Found these figures in the Honda Shop Manual.
9 thou is bang in the middle of the range, as you say the oil ring gap should be slightly bigger.
Interestingly for the 350F the gap is given as 0.1 - 0.3mm for all three rings.
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Title: Re: Piston ring end gap
Post by: stevush on April 19, 2016, 05:32:47 PM

Thanks Chris,
I thought that there may be a difference after a rebore but in hindsight I don't think it matters.

Steve

Title: Re: Piston ring end gap
Post by: Chris400F on April 19, 2016, 09:23:44 PM

Thinking about it (always a dangerous thing to do ....) a rebore to +0.5mm is less than a 1% increase in bore diameter so I wouldn't expect any change in tolerances.