74 z1 piston to head clearance

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74 z1 piston to head clearance

19 Jun 2015 05:26
#677241
Hello I'm new to this forum.
Im rebuilding a 1974 z1 900. I got the block bored to 69mm and the machine shop also had to machine the deck. I would like to check piston to head clearance and valve clearance. Anyone here know what tthe minimum piston to head clearance is for street use?

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Re: 74 z1 piston to head clearance

19 Jun 2015 06:04
#677246
i would want at least .045 thousandths between the piston and head and .080 between the valves and the piston.

imho,

leon
skiatook,oklahoma 1980 z1r,1978 kz 1000 z1r x 3,
1976 kz 900 x 3
i make what i can,and save the rest!

billybiltit.blogspot.com/

www.kzrider.com/forum/5-chassis/325862-triple-tree-custom-work

kzrider.com/forum/5-chassis/294594-frame-bracing?limitstart=0

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Re: 74 z1 piston to head clearance

19 Jun 2015 07:22
#677257
How much did they take off the deck?
Steve
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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Re: 74 z1 piston to head clearance

19 Jun 2015 08:06
#677260
They removed. 020" I haven't checked the clearance yet

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Re: 74 z1 piston to head clearance

19 Jun 2015 09:13
#677269
From the head or barrels?
Steve
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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Re: 74 z1 piston to head clearance

19 Jun 2015 09:28
#677272
From the barrels, the head has not been machined at all

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Re: 74 z1 piston to head clearance

19 Jun 2015 11:37
#677284
prolly be just fine .

always nice for the piece of mind to check tho. :cheer:

leon
skiatook,oklahoma 1980 z1r,1978 kz 1000 z1r x 3,
1976 kz 900 x 3
i make what i can,and save the rest!

billybiltit.blogspot.com/

www.kzrider.com/forum/5-chassis/325862-triple-tree-custom-work

kzrider.com/forum/5-chassis/294594-frame-bracing?limitstart=0

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Re: 74 z1 piston to head clearance

19 Jun 2015 14:10
#677302
69mm, Are they J pistons? High compression?
Steve
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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Re: 74 z1 piston to head clearance

19 Jun 2015 15:06
#677311
Whoops I said 69mm actually they are 68mm and the compression ratio before machining would be 9.25 or 9.5 to 1. Really all Im asking is what is the minimum clearance before the piston would hit the cylinder head.
J piston? Are you talking about the newer J engine? If so it is not a J engine.

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Re: 74 z1 piston to head clearance

19 Jun 2015 15:10
#677313
I just checked again. Actually they are 69mm pistons

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Re: 74 z1 piston to head clearance

19 Jun 2015 15:14
#677314
Mine are 70mm. That's stock 1015. The J's had slightly smaller pistons but higher compression with a different head. I don't have the specs but I'm sure one of our members do.
Steve
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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