100 hrs on 2014 yz450f, shim valves or replace them?

Yamaha YZ450F 2014

79 replies to this topic
  • ttr230rider6

Posted May 02, 2016 - 12:16 PM

#1

Got 100 hrs on my 14 yz450f. I haven't checked the valves yet (I know j should I have). I'm wondering should I buy a shim kit and do that or just buy new pro x stainless steel valves and be done wth it? Along with a pro x timing chain.

Is there much more work involved with replacing valves and springs as opposed to shimming them?

  • Smokeslider

Posted May 02, 2016 - 12:34 PM

#2

If you need new valves, odds are the head will need new seats as well.

  • ttr230rider6

Posted May 02, 2016 - 12:51 PM

#3

[quote name="Smokeslider" post="13085972" timestamp="1462221285"]If you need new valves, odds are the head will need new seats as well.[/

I don't know yet if it needs new valves. It's just starting to get a bit harder to start cold, but it often starts 1st kick once warm. I'm just looking at it like if I have to stuff apart is it just as well to do new valves or just shim with the proper size?

  • grayracer513

Posted May 02, 2016 - 01:09 PM

#4

If you need new valves, odds are the head will need new seats as well.

It's not a Honda.

 

Normally, the seats need very little touch up when replacing valves in a YZ450.  In fact, the seats could probably go through 3 full sets of valves and not need replacing.  They ALWAYS need refinishing when replacing valves.

 

But that's getting a bit ahead of things.  Check the clearance first.  If it even needs to be shimmed at all, there's a good chance that it will only take a one shim size change (.05 mm smaller) to correct it.  If it takes no more than that, you're fine.  If it takes two sizes smaller (0.10 mm) then you can start paying more attention to that valve.  When they need three sizes smaller than the size they originally came with or more (0.15), replace the valve.

 

IMO, No aftermarket stainless valve will seriously outlast the OEM Yamaha Ti valves if the seats are refinished correctly, and all of the SS valves require special heavier spring sets that usually offset any cost savings you get on the valves themselves.

 

As for the Pro-X cam chain, it's the same chain the factory uses (Japanese Borg Warner) for 3 times the price. 



  • ttr230rider6

Posted May 02, 2016 - 01:58 PM

#5

It's not a Honda.

Normally, the seats need very little touch up when replacing valves in a YZ450. In fact, the seats could probably go through 3 full sets of valves and not need replacing.  They ALWAYS need refinishing when replacing valves.

But that's getting a bit ahead of things. Check the clearance first. If it even needs to be shimmed at all, there's a good chance that it will only take a one shim size change (.05 mm smaller) to correct it. If it takes no more than that, you're fine. If it takes two sizes smaller (0.10 mm) then you can start paying more attention to that valve. When they need three sizes smaller than the size they originally came with or more (0.15), replace the valve.

IMO, No aftermarket stainless valve will seriously outlast the OEM Yamaha Ti valves if the seats are refinished correctly, and all of the SS valves require special heavier spring sets that usually offset any cost savings you get on the valves themselves.

As for the Pro-X cam chain, it's the same chain the factory uses (Japanese Borg Warner) for 3 times the price.


Thank you very much for the info, really appreciate it. I will check my clearences and go from there. If they are only off one size I will either get those shims or order a shim kit and just get a new timing chain from the dealer. Thanks again



  • Smokeslider

Posted May 02, 2016 - 05:03 PM

#6

It's not a Honda.

Normally, the seats need very little touch up when replacing valves in a YZ450. In fact, the seats could probably go through 3 full sets of valves and not need replacing. They ALWAYS need refinishing when replacing valves.

But that's getting a bit ahead of things. Check the clearance first. If it even needs to be shimmed at all, there's a good chance that it will only take a one shim size change (.05 mm smaller) to correct it. If it takes no more than that, you're fine. If it takes two sizes smaller (0.10 mm) then you can start paying more attention to that valve. When they need three sizes smaller than the size they originally came with or more (0.15), replace the valve.

IMO, No aftermarket stainless valve will seriously outlast the OEM Yamaha Ti valves if the seats are refinished correctly, and all of the SS valves require special heavier spring sets that usually offset any cost savings you get on the valves themselves.

As for the Pro-X cam chain, it's the same chain the factory uses (Japanese Borg Warner) for 3 times the price.


Thanks for the clarification. Whats the process to touch up the seat? How about refinishing? Are the seats that thick to withstand some massaging through a few sets of valves? Thanks.

  • RMK800

Posted May 02, 2016 - 05:49 PM

#7

When your doing your shims you can go .025 also if there some that are on the edge and you don't need to go the full .05.

  • adam8781

Posted May 02, 2016 - 08:33 PM

#8

100hours isnt anything for a yz450f if its taken care of

 

 

the yzfs are very very durable, Check valves and shim, if they aren't wildly out of spec i would shim and keep riding.

 

if you felt inclined

 

cam chain

new piston

or new piston rings on oem piston

 

http://www.thumperta...before-rebuild/


Edited by adam8781, May 02, 2016 - 08:36 PM.


  • ttr230rider6

Posted May 03, 2016 - 02:16 AM

#9

100hours isnt anything for a yz450f if its taken care of


the yzfs are very very durable, Check valves and shim, if they aren't wildly out of spec i would shim and keep riding.

if you felt inclined

cam chain
new piston
or new piston rings on oem piston

http://www.thumperta...before-rebuild/


That's the plan now I think. Going to take it apart tonight to check my valves. I was reading my Manuel last night to get more familiar with it. I want to replace my timing chain and it says in the manual to replace chain, sprocket and camshaft as a set. Is this necessary? If just doing the chain and camshaft sprocket, does that mean replacing the 2 sprockets up top on the cams?

I was going to leave the piston for now and do it next winter, about 50 hours of riding this season.

I don't ride overly hard. Mostly just jumping in pits and trail riding. Bike only sees redline of doing whips and something goes a bit wrong lol. Oil changed always around 5 hours and oil filter every second oil change and air filter cleaned often.

  • toten

Posted May 03, 2016 - 05:50 AM

#10

I agree that if they aren't way tight you should just replace shims and ride.

 

RMK800, where do you get the .025 shims?

 

Reshimming just means getting to it (pull the tank, probably some other stuff, valve cover - I haven't touched a reverse cylinder YZ), checking/recording clearance, pulling cam caps/cams, replacing shims, reassemble (I might be missing something). Replacing the valves involves all of that and then pulling the head (first remove intake/exhaust setup, maybe other stuff), removing the valves/springs, refinishing seats, reassemble. It's a lot more work. 



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  • grayracer513

Posted May 03, 2016 - 05:56 AM

#11

Thanks for the clarification. Whats the process to touch up the seat? How about refinishing? Are the seats that thick to withstand some massaging through a few sets of valves? Thanks.

 

The seats are a thick ring of cast iron alloy.  The practical limit of how much they can be cut is a matter of whether or not there are shims available tin enough to adjust the valve clearance afterward.  The seat itself could be cut much deeper if it were not for that fact.  The thing is that if valves in this engine are replaced before they become too badly worn, the seats need very little material removed from them to be back to shape.

 

Refinishing valve seats is done by either cutting or grinding (or a combination of both) the valve seat using tooling that centers on the valve guide.  The object is to restore the seat to being a cone shaped cut concentric with and perpendicular to the guide, and the right width and diameter to contact the valve face correctly.  It's a machine shop operation.

 

 

RMK800, where do you get the .025 shims?

 

Honda shops that carry OEM shims will have them for the CRF450.  Same 9.48 mm diameter.  Not all of them do, though, because a lot of shops use aftermarket shim kits in increments of .05 mm.   It's overkill, however, to be that concerned with getting to an exact number. The spec range is .05 wide, and if the valve is actually outside the specified clearance, an .05 mm shim will put it back in spec. 



  • adam8781

Posted May 03, 2016 - 08:58 AM

#12

That's the plan now I think. Going to take it apart tonight to check my valves. I was reading my Manuel last night to get more familiar with it. I want to replace my timing chain and it says in the manual to replace chain, sprocket and camshaft as a set. Is this necessary? If just doing the chain and camshaft sprocket, does that mean replacing the 2 sprockets up top on the cams?

I was going to leave the piston for now and do it next winter, about 50 hours of riding this season.

I don't ride overly hard. Mostly just jumping in pits and trail riding. Bike only sees redline of doing whips and something goes a bit wrong lol. Oil changed always around 5 hours and oil filter every second oil change and air filter cleaned often.

 

 

no just do the chain, i have done this on every 4 stroke i have ever owned, oil changes with filter at 5 hours or so depending how you ride, cam chains around 100, ive done this on 400hour crf450s no issue.

 

I would only run twin air filters with maxima filter oil. I have 3-4 of these new with every bike i own. air filters for 4 strokes are PARAMOUNT importance.

 

replace

cam chain

piston rings

 

new oem gaskets are you go,

 

brapp


Edited by adam8781, May 03, 2016 - 09:02 AM.


  • xcbuckeyeguy

Posted May 03, 2016 - 09:53 AM

#13

IMO, No aftermarket stainless valve will seriously outlast the OEM Yamaha Ti valves


Correct me if I'm wrong Gray. I was told by a Yamaha tech that the 14' and newer no longer have Ti valves. I've not been inside of mine yet to find out, but was under the impression they are now stainless.

Edited by xcbuckeyeguy, May 03, 2016 - 09:53 AM.


  • GHILL28

Posted May 03, 2016 - 10:14 AM

#14

If it's getting hard to start, there are a few other things to check:

 

- Fuel injector (easy to clean)

- Fuel filter (a little harder to clean)

- Fuel pressure (easy to check)

 

I've also noticed that the torque on the center clutch hub nut can affect starting ease just a tad for whatever reason.  40 ft-lbs on that guy with some Loctite, not the 50 ft-lbs the manual states.

 

 

I've been continually surprised that the valves on mine have come to rest at the very low end of acceptable range and haven't budged even a few microns from there.



  • ttr230rider6

Posted May 03, 2016 - 10:50 AM

#15

no just do the chain, i have done this on every 4 stroke i have ever owned, oil changes with filter at 5 hours or so depending how you ride, cam chains around 100, ive done this on 400hour crf450s no issue.

I would only run twin air filters with maxima filter oil. I have 3-4 of these new with every bike i own. air filters for 4 strokes are PARAMOUNT importance.

replace
cam chain
piston rings

new oem gaskets are you go,

brapp


How essential is the importance of doing the piston rings? Just wondering because if I just do the cam chain and shim the valves it seems fairly simple. If I do the rings then the head has to come off = a lot more work haha. But if it is really necessary I will do it. I was going to wait until next winter. 50 or so more hours and do the top end then. But I'll do it now if really necessary. Thanks for the help

  • GHILL28

Posted May 03, 2016 - 10:52 AM

#16

If you have the cams off, it's 4 more bolts and a circlip...

  • ttr230rider6

Posted May 03, 2016 - 11:15 AM

#17

If you have the cams off, it's 4 more bolts and a circlip...


True enough. Perhaps I will replace them. I assume the piston has to come off to do this. Also. Not to sound like a newb, but what exactly is the point of replacing the rings and not the piston? Just wondering so I know how it works haha

  • grayracer513

Posted May 03, 2016 - 11:19 AM

#18

 

 

I've been continually surprised that the valves on mine have come to rest at the very low end of acceptable range and haven't budged even a few microns from there.

 

They are built that way.  The factory sets them as close as they can to the minimum clearance using shims in .01 mm increments to do it. 

 

 

Correct me if I'm wrong Gray. I was told by a Yamaha tech that the 14' and newer no longer have Ti valves. I've not been inside of mine yet to find out, but was under the impression they are now stainless.

 

That would be news to me.  Probably good news, if true.  The SS valves on the '98-'00 models were nearly indestructible, and are a great way to save money rebuilding a later 426.  I'll have to find out. 

 

But it doesn't change anything.  If Yamaha is using stainless in their current OEM valves, there's no reason at all to look to the aftermarket. 



  • xcbuckeyeguy

Posted May 03, 2016 - 11:26 AM

#19

Upon further investigation it clearly states in the service manual the 14' still has Ti valves.

Edited by xcbuckeyeguy, May 03, 2016 - 11:27 AM.


  • grayracer513

Posted May 03, 2016 - 11:39 AM

#20

 Not to sound like a newb, but what exactly is the point of replacing the rings and not the piston?

 

What is the point in replacing something that isn't worn out? 

 

The rings can start to  loose their seal before any significant wear to the piston occurs.  In this case, neither of these components is necessarily signaling that it needs immediate attention by showing symptoms of wear, so the tear down will amount to preventative maintenance.  In such cases, you inspect what you find and decide whether it needs attention or not.  In general, unless the rings are nearly new, you should replace them if you pull the cylinder off.  Whether to replace the piston becomes something like predicting the future.  You can observe and measure the wear you find, then take an educated guess as to how long it will last before it really needs attention, then balance that against whether you want to put it together now, then take apart later to replace the stuff you don't do now, and against the fact that if it isn't completely used up, you're throwing money away in the form of use you didn't get from it.  All this considering that it's much more expensive to wait until something breaks to fix it, and that risk increases the longer you leave things together.







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