Need New Valves....


8 replies to this topic
  • jonova

Posted December 01, 2006 - 11:36 AM

#1

My intake valves on my 01 426 will not hold a clearance. I adjusted them 7hours ago and the clearances were in spec .10-.15mm. Now after just one day they are out of spec. .07mm, .05mm, .10mm. The exhausts are totally fine and still holding from their last shim adjustment nearly 120hrs ago.

So, I believe it's time to do a valve job. I don't want to just buy a new head, because of cost and I have some porting done to my existing head. I figure I will just have the seats re-worked and install new valves, springs, and all the other clips and retainers.

What are some good aftermarket SS valves to use?

Stocks OEM valves are expensive and maybe not the best route to go since I won't be racing this bike anymore.

  • grayracer513

Posted December 01, 2006 - 01:48 PM

#2

What kind of bike is it? 426, or 450?

  • Blue4Ever

Posted December 01, 2006 - 02:04 PM

#3

Kibblewhite makes good stainless steel valves.

  • grayracer513

Posted December 01, 2006 - 04:30 PM

#4

Kibblewhite has a spotty rep due to some troubles a lot of their customers had with them a while back. I haven't heard how that was resolved, but it shouldn't have happened. Feria makes excellent SS valves, however, and even fixed some of KW's problems as if they were theirs. Classy.

However, there really is not anything more reliable than the OEM Yamaha Ti valves, IMO. They last an outrageously long time just as is. The key to their longevity in a rebuilt head is that the valve guides need to be in good shape (they usually are, but they should be checked) and the seats need to be finished properly. Be sure your machine shop knows his stuff.

The other thing to remember is that by the time you buy th espring kit that the heavier stainless valves require, you won't really have saved much anyway. Just use OEM stuff, and save more by buying at TT OEM

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • rexbond007

Posted December 01, 2006 - 07:40 PM

#5

go stock, if you go ss you have to install new seats, OEM will last just as long and will be cheaper. and while your doing that, put in a new timing chain.

  • ONLY4STROKES

Posted December 01, 2006 - 07:57 PM

#6

Kibblewhite makes good stainless steel valves.

I don't really like the two-piece design though...it's too "iffy" for me. Plus I've heard to often about their bad service. Go elsewhere.

TT OEM has big discounts on the best stock equipment. OEM Ti valves are the best.

  • jonova

Posted December 02, 2006 - 08:29 AM

#7

What kind of bike is it? 426, or 450?


It is a 426.

Once the valve seats are machined. The Ti valves are just installed and don't require any lapping right? But the SS valves do.

So if the Ti valves don't require lapping once the seats are machined and guides check I will just install them back into the head. I will also buy new springs retainers and such. Or can the retainers be re-used?

What is the cost of the OEM valves from the TT Store? I get most of my parts from a local shop that is about the same price as mrcycles.com. An intake valve will cost me $65.

Can the timing chain be replaced by taking off the stator and flywheel?

Thanks for your helps guys.

  • grayracer513

Posted December 02, 2006 - 10:17 AM

#8

It is a 426.

Once the valve seats are machined. The Ti valves are just installed and don't require any lapping right? But the SS valves do.

So if the Ti valves don't require lapping once the seats are machined and guides check I will just install them back into the head. I will also buy new springs retainers and such. Or can the retainers be re-used?

A whole set of springs is about $40 retail. Replace them whenever you have the opportunity. It's the cheapest insurance you can get. The retainers and keepers are usually usable. They can be inspected for damage. The machine shop should finish grind the seats (not cut), and then the valves are installed and the clearances set. Be sure, if you do the valve adjustment on the bench, that you recheck them once the head is torqued.

What is the cost of the OEM valves from the TT Store? I get most of my parts from a local shop that is about the same price as mrcycles.com.

An intake valve will cost me $65. $56 for an intake for a 450. You'd have to call for a price on a 426 part.

Can the timing chain be replaced by taking off the stator and flywheel?

Yes.

  • rexbond007

Posted December 02, 2006 - 10:19 AM

#9

It's not that ti valves don't require lapping. If ti valves are lapped, the coating on the valve gets worn off and go to mush. you will be replacing valves again.
when i installed valves in my wr 250 i just dropped them in, and made sure the seats had no nicks and there was a good seat.

http://www.members.s...-new-valves.jpg
http://www.members.s...old-and-new.jpg
http://www.members.s...lve-new-old.jpg
http://www.members.s...d007/piston.jpg

i re used my springs, but i knew i was not keeping the bike for long. but do change the timing chain for $40 what i paid it's worth it.
gray racers comments a to grind seats is a must.





Related Content

Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo
Motocross

Thinking about Yamaha 250... by Arctic Pride


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies
Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.