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Author Topic: 1975 Super Sport Piston Rings/Piston ID  (Read 848 times)

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Offline CShipes

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1975 Super Sport Piston Rings/Piston ID
« on: December 28, 2017, 12:41:59 PM »
Hello all,

Working on my 1975 CB750F barn find and noticed the piston rings were in pretty bad shape so I decided to just replace them all.

I ordered 4 sets of the Riken STD rings and they are too tight. I also noticed that my pistons look odd compared to all the pictures of similar bikes’ pistons. I’m thinking maybe they’re aftermarket. The pistons are 66.5mm in diameter. I couldn’t identify them as there are no numbers, letters, etc. anywhere.

Anyone have any advice?
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Offline Bankerdanny

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Re: 1975 Super Sport Piston Rings/Piston ID
« Reply #1 on: December 28, 2017, 03:42:30 PM »
If they are oversize there is generally a mark of some sort on the top of the piston, but you will likely need to clean off the carbon to find it.

Are the ring grooves completely clean?

You may need to have a machine shop double check the piston and bore sizes.
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"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline danyo

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Re: 1975 Super Sport Piston Rings/Piston ID
« Reply #2 on: December 28, 2017, 03:53:19 PM »
Standard bore is 61mm so your pistons are way to big for standard rings.

Sent from my SM-N900T using Tapatalk

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Offline BPellerine

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Re: 1975 Super Sport Piston Rings/Piston ID
« Reply #3 on: December 28, 2017, 04:27:13 PM »
might be a 900 kit in there,67mm
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1978 CB 750K ard and webers
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Offline CShipes

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Re: 1975 Super Sport Piston Rings/Piston ID
« Reply #4 on: December 28, 2017, 06:06:31 PM »
Just found out that it’s the CycleX 849cc kit. A welcome surprise. Guess I should have looked at it more before ordering parts ... lol.

Thanks for the help.
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