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Soft intake valves on YZF?
Posted: Fri Sep 09, 2005 5:29 am
by craigy
I have a question for all you EXUP brotherhood folk, does the YZF 750 have an underlying problem with soft intake valves ?<br><br>Regarding my previous post (YZF won't start) which was found to be the intake valves closed off i had a look about the internet for information regarding this issue and found this :<br><br><!--EZCODE AUTOLINK START--><a href="
http://www.google.co.uk/url?sa=t&ct=res ... <!--EZCODE AUTOLINK END--><br><br>i hope that link works, if it does and you have adobe acrobat insalled to read the thing then look on the page on the right hand side and you will see an article called YZF intake valve appetite.<br><br>I have a concern with mine at the moment seeing as, if the clock is correct i have only done about 19k and on the shim check it looks to have been re-shimmed previous, i can tell as some still have numbers on the shims showing while others have not.<br><br>So i'm at 19k and onto a second shim job with the valve clearences closed tight, has anyone alse noticed such problems with their YZF ? <p></p><i></i>
Re: Soft intake valves on YZF?
Posted: Fri Sep 09, 2005 8:09 am
by dragracer1951
My FZR required 20 new valves at 27K miles<br>Yamaha specs 24K between shim checks and mine had been checked at 18K...All of the valves in my motor had the lips beat up. I replaced them with 1mm over Manly stainless valves and 2K ago when I had the motor open they looked great with 13K on them...<br>I would not let a stock valved Yamaha go more than 12 or 13K between valve checks.<br>Also...numbers or nor on shims is not a way to tell if they have been done. I have bought factory shims for Yamaha, Suzuki, Kawasaki and all of them came both ways...numbers or not... <p>Jim <!--EZCODE IMAGE START--><img src="
http://img.photobucket.com/albums/v209/ ... Cheers.gif" style="border:0;"/><!--EZCODE IMAGE END--><br><br><!--EZCODE IMAGE START--><img src="
http://img.photobucket.com/albums/v209/ ... states.gif" style="border:0;"/><!--EZCODE IMAGE END--><br>Hey Kid...Is my taillight working?</p><i></i>
Re: Soft intake valves on YZF?
Posted: Sat Sep 10, 2005 4:03 pm
by craigy
Thanks for the reply, good news i got the new shims in today and the bike fired first time <!--EZCODE EMOTICON START :banana --><img src=
http://img.photobucket.com/albums/v209/ ... ananna.gif ALT=":banana"><!--EZCODE EMOTICON END--> <!--EZCODE EMOTICON START :banana --><img src=
http://img.photobucket.com/albums/v209/ ... ananna.gif ALT=":banana"><!--EZCODE EMOTICON END--> <br><br>I was over the moon, the shims i'm using <p></p><i></i>
Re: Soft intake valves on YZF?
Posted: Sat Sep 10, 2005 4:09 pm
by craigy
range between 1.45mm and 1.55mm so they are getting close to the min spec of 1.20mm , so if i have to re-shim again to often if won't be long until i run out of options and have to look at getting the valves out. You don't get much life out of these intake valves that's for sure, i'll run the bike for now and see how it goes.<br><br>Thans for all the help guys tis appreciated i'm back on the road <!--EZCODE EMOTICON START :riding --><img src=
http://img.photobucket.com/albums/v209/ ... iker_3.gif ALT=":riding"><!--EZCODE EMOTICON END--> <br><br>excuse posting problem not sure what happened there<!--EZCODE EMOTICON START :o --><img src=
http://www.ezboard.com/images/emoticons/embarassed.gif ALT=":o"><!--EZCODE EMOTICON END--> <p></p><i></i>
Re: Soft intake valves on YZF?
Posted: Sun Sep 25, 2005 5:30 am
by creed12r
<br> 1.2mm to 1.45mm is 10 thou give or take a gnats @#%$.<br> I would think it will take a while before the valves sink into the seats by that much! like 100 thousand miles, so I shouldn't think a rebuild is immenent just yet!<br> chris <p></p><i></i>