Valve Adjustment

Anybody adjust their valves on their brand new 450 yet? I just hit 10 hours and checked them this morning. Exhaust valves were in spec, right in the middle of the window. Intake valves were both out of spec by .02 (too tight). I adjusted them and now they are right in the middle of the window.

This was my first time ever getting into a four stroke motor and it was surprisingly easy. I am surprised, however that my valves needed adjustment at only 10 hours, especially considering it's a 450 and I'm not bouncing it off the rev limiter all the time. Is this normal?

Edited by CSAR FE

Anybody adjust their valves on their brand new 450 yet? I just hit 10 hours and checked them this morning. Exhaust valves were in spec, right in the middle of the window. Intake valves were both out of spec by .02 (too tight). I adjusted them and now they are right in the middle of the window.

This was my first time ever getting into a four stroke motor and it was surprisingly easy. I am surprised, however that my valves needed adjustment at only 10 hours, especially considering it's a 450 and I'm not bouncing it off the rev limiter all the time. Is this normal?

They may have been out of spec from factory, just keep an eye on them and see if they change in another 10 hours.

The bike ran pretty good before but when it was hot sometimes it would take 5-6 kicks to start it and other times only 2-3 kicks so it makes sense that they were out. I ran the bike after the adjustment for about 5 minutes and shut if off, then started it hot and it fired up with only one kick.

I talked to my buddy on the phone a minute ago who is a mechanic and he said that's not really normal to need to adjust them at 10 hours but every hike is different.

The bike ran pretty good before but when it was hot sometimes it would take 5-6 kicks to start it and other times only 2-3 kicks so it makes sense that they were out. I ran the bike after the adjustment for about 5 minutes and shut if off, then started it hot and it fired up with only one kick.

I talked to my buddy on the phone a minute ago who is a mechanic and he said that's not really normal to need to adjust them at 10 hours but every hike is different.

Yeah the 5-6 kicks hot would indicate valves needing adjustment. Like I said, maybe they were out from the factory. Just keep an eye on it.

Thanks for the reply.

Gray, looking for your input as well.

Edited by CSAR FE

.02 mm?  You realize how small that is?  It's a smidge less than .00079".  Two people could read more difference than that with the same feeler gauges. My guess is they were OK to start with, but I'm not there.

Yes, I realize how small that is. Again, I'm learning here, but seeing that the clearance for the intake valves is only a .07mm window, I guess .02 outside of spec has to be at least somewhat significant.

If accurate.  You say this is your first try at valve adjustment, and I don't know what your previous mechanical experience, training, etc., is like, but I do know that a lot of people have trouble getting the feel of feeler gauges well enough to tell .02 from .04 mm.

 

Either way, Yamaha has historically set up all their YZF's at as near the minimum specified clearance as possible, and they use shims in increments of .01mm to do it.  So, the likelihood is that the intakes haven't moved any more than .02mm to get to where you found them.  It isn't unusual to find a couple of valves that settle in a little ways, though.  Reinspect in another 10 or so and see how it is then.  May not change at all.

Thanks gray. I'm pretty mechanically inclined and am pretty familiar with using feeler gauges, micrometers, ect. The minimum clearance was .13mm per the manual and I couldn't even get a .127mm in (my feeler gauges are missing a couple).

After adjustment, I could get the .153mm gauge in with just a little bit of stiction, which is almost in the middle of the allowable clearance range.

Anyways, like you said, I'll check again in 10.

Probably a stupid question, but when you say you adjusted your valves, did you need anything extra to put in there? Like other shims or did you have to buy anything? I was always under the impression you had to add shims but by the way it sounds you just had to adjust what was there? I've never checked valves before and I want to check mine on my 2014 450f

If the clearance is out of spec, you remove the shim, or lash adjusting pad, which looks like a 1/4" steel hockey puck, and replace it with an alternative sized shim to correct it.  The process is explained in the manual.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now