motorbike bottom end

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karter13
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motorbike bottom end

Post by karter13 » Sun Jun 19, 2016 5:23 am

Question
I have a four stroke motorbike engine (crankshaft-rod-bearing assembly) and I want to check the clearances

crankshaft end play
big end bearing cage side clearance
crankshaft run out
etc

question is even though it is a four stroke engine (crankshaft-rod-bearing assembly) can I set the clearances up the same as if it was a two stroke engine (crankcase-rod-bearing assembly set up).

clearances I would use will come from a graham bells two stroke performance tuning (onto my four stroke engine).
thanks Steve.

Kevin Johnson
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Re: motorbike bottom end

Post by Kevin Johnson » Sun Jun 19, 2016 1:07 pm


karter13
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Re: motorbike bottom end

Post by karter13 » Sun Jun 19, 2016 4:34 pm

Kevin johnston
Sorry for any confusion i am asking if it ok to set up the bottom end of a four stroke engine to the clearance specs of a two stroke in the case of a motorbike engine.

Thanks for your reply and picture in advance
Regards steve.

Kevin Johnson
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Re: motorbike bottom end

Post by Kevin Johnson » Sun Jun 19, 2016 7:55 pm

I think people will need to know what specific engine and what specific components you are using in it. You can see from the other thread that there are a wide range of opinions. I put up the picture from the book you are referencing so other readers will know what clearance values you are referring to.

karter13
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Re: motorbike bottom end

Post by karter13 » Sun Jun 19, 2016 8:25 pm

1990/91 honda xr200 stock parts

Kevin Johnson
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Re: motorbike bottom end

Post by Kevin Johnson » Mon Jun 20, 2016 7:17 am

Hi Steve,

The manual for your engine can be found here: http://www.mediafire.com/download/t7ldj ... Manual.pdf

You will find the measurements needed on 10-4 and 10-5.

Side clearance at connecting rod big end service limit: 0.80mm (0.032 in)
Radial clearance at connecting rod big end service limit: 0.05mm (0.002 in)
Crankshaft run-out service limit: 0.05mm (0.002 in)

karter13
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Re: motorbike bottom end

Post by karter13 » Mon Jun 20, 2016 2:47 pm

To easy thankyou kevin johnston

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