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valve timing

Posted: Sat Nov 23, 2013 8:58 pm
Author: alinus65
hi,

I removed both cam shaft because I was not able to take 2 shims even with the special tool.
Today I have assemble everything following this instruction:

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my bike is z1b and there are some differences:

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Do you have instruction for camshafts installation in simple words?

One more problem.
By mistake I turned by hand the cranshaft with the special purpose tool installed. Do you think I damage the valve?
The shim on that valve was 280 and clearance 0. I put shim 270 and now clearance is 0,20. Is it a sign that valve is damage.

Sorry for my English...

Ciao

Posted: Sat Nov 23, 2013 9:26 pm
Author: z1bman
if you look at the end of each camshaft you will see a section cut out from from the cam. with the engine set to top dead centre on 1&4 cylinder half of this cut out section should be below the cylinder head mating surface when the valve timing is correct. inlet cam cut out should be facing towards the rear & the exhaust cam cut out should be facing foward. as for the valve being bent / damaged make sure your valve timing is correct then do a compression test

Posted: Sat Nov 23, 2013 10:15 pm
Author: chrisNI
Unfortunately the valves can bend pretty easily, don't want to worry you but if a clearance changed it doesn't sound good... :?? Put the same 280 back in and double check in case the 270 is worn.

Been there... Good luck :oops:

Posted: Sat Nov 23, 2013 10:40 pm
Author: z1bman
it would be very unlikely for a shim to wear as they are hardened

Posted: Sun Nov 24, 2013 11:33 am
Author: zed1015
Shim wear is common. They end up dished and thinner towards the centre . In extreme cases they can fracture if removed and refitted the other way up.

Posted: Mon Nov 25, 2013 9:44 am
Author: alinus65
Thanks for your valuable suggestions.
Yesterday I managed to install properly (I believe) the cam shafts.

I have checked the clearance and I am afraid that one valve has bent.
I am talking about intake valve cylinder 4.
Before it was clearance zero with 280 shim.
I put 270 and now clearance is 0.45. This is the warning of valve bent :( :( :( .
What do you suggest in such case.
My plan is to put 305 shim fire the bike and check compression.
What do you think?

I am really pissed off. Bike was running fine except for a bit of hesitation at low rpm in acceleration.
Winter is time to make damages. Better ride the bike in summer

Ciao
:D

Posted: Mon Nov 25, 2013 10:10 am
Author: z1bman
just leave your shims as they are do not replace the shim for a 305 as this will remove all the clearance from the valve . for a good compression reading you need clearance in the the valves

Posted: Mon Nov 25, 2013 10:38 am
Author: alinus65
With 305 I should have 0.1 clearance. Am I right?

Ciao

Posted: Mon Nov 25, 2013 1:35 pm
Author: chrisu
if you've bent the valve then it'll need to be replaced - head off job i'm afraid.

no real alternative.

Posted: Mon Nov 25, 2013 3:02 pm
Author: alinus65
chrisu wrote:if you've bent the valve then it'll need to be replaced - head off job i'm afraid.

no real alternative.


Do you believe that such clearance increase means valve bent? We are talking about 0.30 clearance increase.
Which are the risk to fire the bike and test compression?
Thanks

Posted: Mon Nov 25, 2013 5:08 pm
Author: z1bman
just run the bike as it is for the compression test it will just be a bit noisy but wont do any harm

Posted: Mon Nov 25, 2013 5:50 pm
Author: chrisu
alinus65 wrote:
chrisu wrote:if you've bent the valve then it'll need to be replaced - head off job i'm afraid.

no real alternative.


Do you believe that such clearance increase means valve bent? We are talking about 0.30 clearance increase.
Which are the risk to fire the bike and test compression?
Thanks



a sudden increase in valve clearance like that then typically yes.

As Z1Bman says - run it if you like - a compression test will show that cylinder way down if the valve is bent.

Posted: Sun Jan 12, 2014 12:01 pm
Author: alinus65
At the end I found a very good mechanic.
6 valves was bent.
Work has been done properly.
Carbs have been cleaned as well.
Now bike is smooth like silk. :D

Posted: Sun Jan 12, 2014 12:13 pm
Author: wilsonsjw11
It's good you got there in the end.
Now enjoy the bike :D
Regards
Steve