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post #1 of 9 (permalink) Old 06-20-2019, 05:48 PM Thread Starter
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Zx7r rebuild

Hi guys

I'm hoping to get some help from some experts.
I am rebuilding my zx7r p4 engine. Big bore 779ccm wiseco kit.

The rebuild has started but my mechanic has come back saying the crank I have is no good journal crank pin is worn and is out of spec.

My.might has a newly machined balanced to 14k L modell crank. He says that with this crank it is a straight swap and all I need is to buy a thicker base gasket. He says 1.3mm base gasket. He also says this will.bring the bike to around 835ccm.

Can someone please confirm if this is correct before I spend $$$
Thanks in advance guys :)
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post #2 of 9 (permalink) Old 06-22-2019, 06:49 AM Thread Starter
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I have ordered this :

I will go 20 thou copper base and 40 thou MLS head to get 60 thou / 1.50mm total. We can always work our way down if too thick .
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post #3 of 9 (permalink) Old 06-22-2019, 03:10 PM
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Just built one of these recently. L model crank with 74mm pistons.
I used a 1.3mm base gasket with standard thickness head gasket. If more clearance is needed, I would add OEM base gasket. I personally don’t like adding thickness at the head gasket.
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post #4 of 9 (permalink) Old 06-23-2019, 01:35 AM Thread Starter
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Hey man


I got the 74.5mm wiseco.
So you are saying put the 1.3mm base basket and use stock size head gasket?
We thought we might have add a bit thicker one to the head to get 1mm squish .
I've already ordered the above sizes but.if it is too thick we can always move down sizes .

Cheers
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post #5 of 9 (permalink) Old 06-23-2019, 01:36 AM Thread Starter
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Oh and why dont you like adding thickness to head ?
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post #6 of 9 (permalink) Old 06-23-2019, 07:31 PM
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Personal preferences. I would rather run a 1.3mm base gasket and adjust height from there. If you try to adjust anything other than squish with head gasket thickness, I think you may be asking for trouble. Piston deck height is what you need to adjust first, then squish area.
Just my preference, not the final word. Others may/will express a better way or a preference as well. Just my 2 cents.
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post #7 of 9 (permalink) Old 06-24-2019, 03:17 PM
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I simply used Cometic base gasket (1.3mm) and their head gasket as well. These two gave me ideal clearances (.62mm) squish. These are the exact pieces I used for my build.
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Last edited by ninjanut; 06-24-2019 at 03:20 PM.
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post #8 of 9 (permalink) Old 06-30-2019, 11:59 AM
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You can also check out Turbo’s build. “It’s not over” build thread on this Forum.
I think he did the 779cc build as well as a few other tricks!!
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post #9 of 9 (permalink) Old 07-28-2019, 10:08 PM
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Following, heading down this path as well soon
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