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Discussion Starter #1
Ok im new to this bike thing (well experienced in cars) remember that as I ask this question.
I have quite a bit of valve noise. I was told by the previous owner that I need to adjust the valves.
Is this a relatively easy undertaking? And what should i expect in the undertaking of this?
I can build a car from the ground up so im not scared, I just want some insight from you bike guru's

And the bike is an 81 Yamaha xs400

thanks
K-

http://www.myspace.com/5pecial_k
 

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Can't speak about that bike inparticular...but most Japanese bikes you just pull off the valve cover (tappet cover). Get out your feeler gauge and a couple of 8 or 9mm wrenchs and go to town.
Put the piston at TDC on the compression stroke...(or wherever the manual tells you to) check the clearance before you start....loosen the locknut on the tappet...adjust the tappet (tiny square ended screw typically), re-tighten the locknut.
I'd strongly advise getting a service manual if you don't have one...every bike has little particulars when it comes to stuff like this. Most tappets start getting noisy around .006". Typical Honda clearance on intake and exhaust is .002" ....so yes..pretty tight.

No different than an old "solid lifter" hot rod. Remember..too loose is way better than too tight.
JohnnyB
 

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Discussion Starter #3
mucho thanks!
I have a haynes manual on the way. Hopfuly that will have some particulars in it.

Do you know what the big bolt cover lookin thingy's (technical term) on the front of the valve cover? they appear to be some sort of access to the valvetrain.

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Typically that big bolt thingie...usually around 19mm...is the tappet cover...The XS400 should have four of them I think.
The tappet adjusters should be under there. Unless you have the rare DOHC XS400.

Some Yamaha guy here correct me if I'm wrong...but I think they use a similar setup to Hondas...four tappet covers, two front, two back.
JohnnyB
 

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yes; those big thingies are the tappet covers. don't forget the cam chain tensioner adjustment (if it's not automatic). remove all of the covers and turn the engine over by hand; watch the intake valve on the cylinder closest to you and when it goes down, keep turning until it comes back up. the next time the rotor hits TDC is usually where you set the valves at.

BTW: how do i get those funky stars under my profile?

if at first you don't succeed, use a bigger hammer

Edited by - peten on Jul 13 2007 3:33:33 PM
 

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its either a post rating, or what kind of relationship you have with jeremy. youll notice, a few of us have several red "stars" well.....you figure it out.

the 350s are 003 and 002 according to the book. stock.

just be glad its not bucket and shim. or bucket over shim....ug.


jc
 

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oh yeah, it sounds like ya know whats up....if you need help, you can probably talk to ross and bring it by the shop one day. we're just north of highland town near eastern ave right off 40.

jc
 
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