another valve question


26 replies to this topic
  • arcboy

Posted June 02, 2008 - 03:53 PM

#1

I have searched for adjusting valves on my 01 WR 426 and couldn't find detailed info on pics or procedures on checking and adjusting valves. I have the manual but still would like some pointers or checking out a write up on doing it.

Thought I might just take it in but I am pretty sure I can do it.

  • matt4x4

Posted June 03, 2008 - 04:12 AM

#2

you can do it and if you wait a week, I'm in the process of putting something together, have some pics already but waiting on parts to put the engine back together before I can take those last few pics I need that deal with what portions of the bike to remove, can chain removal, cam removal etc.

  • matt4x4

Posted June 03, 2008 - 08:06 AM

#3

here's a quick one to get you going on checking them if you REALLY need to know.

1. Take off shrouds, seat, plug boot, blow air in teh hole at the bottom of the plug to get any dirt out while the boot is off
2. Shut off petcock, remove fuel line from carb.
3. Remove gastank - 2 bolts near front, one clip under seat
4. Remove upper engine mounts (4 bolts, 2 plates)
5. Remove 2 hoses off top of head cover, remove 2 screws holding down cover.
(Imagine this is ON the bike)
Posted Image

6. Once you have the cover and gasket off, take the two plugs on the left of the bike (stator cover) off, get the appropriate (14mm??) socket and turn the crank until you see the TDC mark (engine should get hard to turn as you approach it and you might have to use decompression lever - only for non auto dec. bikes).

7. Check valve lobes - should be pointing out sideways
8. take your feeler gauge and start to feel clearances like shown - they should fit snug, you should NOT force them in.
Posted Image

NOTE: You can stack two feelers to get different values if your gauges don't have the appropriate ones for your needs, for instance, I have a .279 and the next down is a .203, but if I stack the .203 and the .051, I can also have a .254......

Posted Image

On that pic, you also see the shims, the numbers on them sometimes wear off, some of mine read 84, when in fact they're 184.

Anyways, that's the quick and dirty on measuring clearance, I don't have much more to give you right now to do the rest, but this will get you started until I get parts and pics for writing the whole thing......

  • arcboy

Posted June 03, 2008 - 02:36 PM

#4

That is exactly what I am looking for. Post the rest of the pics when you get done.

  • grayracer513

Posted June 03, 2008 - 03:16 PM

#5

http://motoman393.th...ech/valves.html

and/or

http://www.thumperfaq.com/valves.htm

(this second link is for a 250F, but only the valve specs are really different. the process is exactly the same.)

  • martin450

Posted June 04, 2008 - 05:24 AM

#6

great explanation , Thankyou :thumbsup:

  • arcboy

Posted June 04, 2008 - 04:38 PM

#7

Well that seems easy enough. Sort of hard to tell where the shims are but I am sure I will see them better once I get it apart.

I am the type of person who will always second guess themselves and always worry if I did it right and just wait for it to break. Usually doesn't but I still worry.

  • chickenstrips

Posted June 04, 2008 - 08:49 PM

#8

Well that seems easy enough. Sort of hard to tell where the shims are but I am sure I will see them better once I get it apart.

I am the type of person who will always second guess themselves and always worry if I did it right and just wait for it to break. Usually doesn't but I still worry.


The shims are underneath the followers or lifters. They usually "stick" to the bucket, so make sure as soon as you pull the lifter up you put your other hand underneath the lifter incase the shim falls out, dont want it going into the motor. When you find the new shim sizes, insert them into the "hold" on top of the valve retainer and make sure its seated, then install the lifter.

  • matt4x4

Posted June 05, 2008 - 04:25 AM

#9

I didn't show you the shim location because it is NOT required for CHECKING only, I don't have everything together yet (pictures) to do a writeup of the whole procedure.
But if you want to know, once you have checked them AND they require adjustment, you have to take the cam(s) off (mark chain and cam with grease pencil for reinstalling), under which you see the buckets - only ever remove one at a time - never mix them up.
You are supposed to use a special tool to pull the buckets (suction cup) but I just wipe them and use sticky tack. It's also a good idea to stuff a rag into the timing chain passage so things DON'T fall into the bottom end.
If you have manual decomp. remove the bolt on teh left side and slide the decom. lever out some:
Posted Image

decomp lever partially covering bucket at top of pic:
Posted Image

Decomp lever slid back out of way - (bucket fully exposed)
Posted Image

Sticky tack:
Posted Image

This pic shows a pulled bucket, flipped to expose the shim stuck to the bottom - needle nose will pull it off, read the size and either calculate what you need from there or use the reference chart in the manual
Posted Image

like I said, I don't have everything to do a complete writeup yet, but this should help you a bit.

  • m1ke234

Posted June 05, 2008 - 10:42 AM

#10

Thanks for putting together a procedure, my black and white downloaded manual is hard to see what I'm instore for a when I take the valve cover off.....

This may be obvious, but just wanted to make sure, I am a new owner to 4-strokes, the clearance we are checking is between the lifter/bucket and the camshaft lobe when we are in the compression stroke, so this is valve closed clearance similar to a solid lifter car?

Where do you buy the shims, The Yamaha stealership?

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  • SJMC_DON

Posted June 05, 2008 - 11:20 AM

#11

Shims are hard to come by on a one by one basis. I bought a hotcams shim kit but it came with two ranges, one of which must be for some other kind of bike because you will not need them in a Yamaha.

I use a small telscoping magnet to pull the buckets, it works real well.

Don't forget to go get some moly assembly lube before you start adjusting valves. I also suggest checking out Grey Racers method for cam installation / timing it will save you some time and heart ache:thumbsup:

  • grayracer513

Posted June 05, 2008 - 02:44 PM

#12

Single shims should be easy to get if you live near a large Honda dealer. The CRF450 uses the same 9.48mm diameter shims the YZ450 does, and they have enough call for them that they usually keep a good assortment on hand.

  • matt4x4

Posted June 06, 2008 - 04:02 AM

#13

and they have enough call for them that they usually keep a good assortment on hand.

HAHA - I like that comment Grey - very accurate
Also, Honda makes them in more tolerances than Yamaha does - likely for similar reasons!

Yes, you check them at TDC, lobes pointing outwards.
Stealerships can get them - TT OEM has great prices on them, Honda dealers can likely retire quite comfortably on selling shims alone.

  • arcboy

Posted July 13, 2008 - 10:44 AM

#14

Finally started to do the inspection today. I will find out shortly if I have to replace the shims.

I Just looked through my PDF of a manual and I must be retarded or blind because it tells me to inspect the valves but doesn't have the part where it shows me how the steps nor does it give me any specs and tolerances. I couldn't find any specs on here either.

  • arcboy

Posted July 13, 2008 - 11:23 AM

#15

I also just realized that I don't know what exact TDC is. I can see the mark "I" and "H" and I know that the "I" on the top hole and they are supposed to line up with what? If I see the "I" in the top hole does that mean that it is a TDC?

  • Demo_Slug

Posted July 13, 2008 - 12:47 PM

#16

I also just realized that I don't know what exact TDC is. I can see the mark "I" and "H" and I know that the "I" on the top hole and they are supposed to line up with what? If I see the "I" in the top hole does that mean that it is a TDC?


don't know anything about the 01. but on my 08 the "H" is TDC. and I was told that the "I" is the ignition mark. I line up the "H" to the top of the hole.

in regards to checking valves. TDC is not all that important. just make sure that the cam in not pushing on the spring bucket or close to pushing them. its pretty obvious because you wont be able to put a feeler in there.

  • WR450FGreg

Posted July 13, 2008 - 01:42 PM

#17

.
arcboy,

"TDC" is Top Dead Centre.
The piston is at the very peak of it's stroke.

Greg

  • WR450FGreg

Posted July 13, 2008 - 01:43 PM

#18

I also suggest checking out Grey Racers method for cam installation / timing it will save you some time and heart ache

.
Handy information.

cheers,
Greg

  • grayracer513

Posted July 13, 2008 - 07:26 PM

#19

don't know anything about the 01. but on my 08 the "H" is TDC. and I was told that the "I" is the ignition mark. I line up the "H" to the top of the hole.

You were told wrong. The manual explains this. "I" is TDC, and "H" is for ignition timing. But for the sake of checking valve clearance, it's close enough.

What these marks are supposed to line up with is a small notch cut in the top of the top timing plug hole. Again, this is explained in the manual

  • matt4x4

Posted July 14, 2008 - 04:48 AM

#20

Another way to verify TDC is:
Once you've pulled the valve cover, also pull the spark plug - stick an 8" socket extension or similar straight object in the spark plug hole, when the H is up near the mark, the extension will also be at it's highest point - showing you that the piston is at it's highest point - thus TDC.

Sorry I never got the whole pictorial done and pics of taking it all apart in a step by step format - the parts were SO delayed, by the time they finally showed, I just slapped it all back together and went riding - that just seemed so much more important!




 
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