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Honda CB450 SUPER SPORT 450 K1 US Forum


Honda CB450K1 1968 USA

1970 CB450 Rocker Arm Ratio

Honda CB450 SUPER SPORT 450 K1 US Forum

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David Tye

posts: 2
posted: Tuesday, January 10, 2012 01:48
Subject: 1970 CB450 Rocker Arm Ratio

I am building a classic racebike from a 1970 CB450 and have a set of aftermarket camshafts where I know the cam lift but not the valve lift. Does anyone know what is the rocker arm ratio is so i can work out the valve lift?

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Jim Milsted

posts: 1
posted: Saturday, January 21, 2012 17:11
Subject: Re: 1970 CB450 Rocker Arm Ratio

I am building a classic racebike from a 1970 CB450 and have a set of aftermarket camshafts where I know the cam lift but not the valve lift. Does anyone know what is the rocker arm ratio is so i can work out the valve lift?


Hello, I drag raced these for a few years in many engine combinations but did not write the details as that was about 40 yrs. ago. First I would recommend that you get an original factory HONDA SHOP MANUAL. READ IT AND RE-READ IT OVER & OVER. I learned so much from it. If I remember it right the ratio was like 1.5 to 1.6 to 1. Depends how you adjust them, to factory specs that's the ratio. If you adjust how they say "NOT TO", it is more. Because the adjustment is on an "eccentric". I used to clamp the head upside down in a vise and put a dial indicator on the valve face and then turn the cam over to check the lift. We weren't super smart on this stuff back then, just learning as we went along. I have nothing from back then now except good memories & pictures, and the SHOP MANUAL. Hope this helps you out.

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David Tye

posts: 2
posted: Sunday, January 22, 2012 01:09
Subject: Re: Re: 1970 CB450 Rocker Arm Ratio

Hi Jim, Thanks so much for your reply. Have sourced a factory shop manual and will spend some quality time with it on the lounge.. Appreciate the assistance.. Cheers David

I am building a classic racebike from a 1970 CB450 and have a set of aftermarket camshafts where I know the cam lift but not the valve lift. Does anyone know what is the rocker arm ratio is so i can work out the valve lift?


Hello, I drag raced these for a few years in many engine combinations but did not write the details as that was about 40 yrs. ago. First I would recommend that you get an original factory HONDA SHOP MANUAL. READ IT AND RE-READ IT OVER & OVER. I learned so much from it. If I remember it right the ratio was like 1.5 to 1.6 to 1. Depends how you adjust them, to factory specs that's the ratio. If you adjust how they say "NOT TO", it is more. Because the adjustment is on an "eccentric". I used to clamp the head upside down in a vise and put a dial indicator on the valve face and then turn the cam over to check the lift. We weren't super smart on this stuff back then, just learning as we went along. I have nothing from back then now except good memories & pictures, and the SHOP MANUAL. Hope this helps you out.

reply to this