Are my Valve readings correct?

I am hearing, all of a sudden, what seems like much more engine rattling noises than normal so I checked my valve clearance today.

I believe they are still in spec. Can I get your opinions on that?

Exhaust (.25 - .30mm is spec)

.25 slid in easy

.28 slide in with minor resistance

.30 went in but I had to really push hard

.33 did not go in

Same for both

Intake (.15 - .20mm is spec)

.15 went in easy

.20 went in with hard resistance

.25 would not go in

Same for all three

So I have two questions:

1 - Are they in spec.

2 - what could be making all that noise all of a sudden.

One thing I did notice was that when the timing mark was lined up right on, the two intake marks on the cams did not line up with the top of the engine. I moved the timing mark very slightly to the right and then the cam timing marks were right on with the top of the engine. that is when I measured.

When I did the YZ timing about 6 weeks ago all the marks were right on.



Dougie, '99 WR400

Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

[This message has been edited by Dougie (edited 05-15-2000).]

Could it possibly be your cam chain? You can check to make sure your tension is ok. You could wind it up, then realease it.

Or is it one of those sounds that are always there, but you have never really noticed until now?

My 650 Seca Yamaha had a lot of cam chain noise, but that was NOT auto adjusting. My chain was loose.

[This message has been edited by Kevin in New Hampshire (edited 05-15-2000).]


Your valve lash adjustments sound fine to me. I also am hearing or think I'm hearing a lot more engine noise than before?? I also checked the valves, checked the cam chain etc and all cheded out OK. Im also noticing some stuff on my oil filter, some magnetic some not. But since I change my oil every 200 miles or so I'm not sweating it. I'm just going to keep riding it damn hard and if it blows report it and then build it again. The Bike is running great otherwise, so I'l just keep on trucking.

I wonder if its that carburetor slide valve plate slapping around or maybe the new harder plastic/nylon chain guide I just added after going through four (4) stock guides.

Time will tell hope its not a time bomb that goes off before I get my Power Bomb.


This might be bleedin' obvious, but have you recently installed an alloy bashplate - these make your engine sound like its going to jump out of the frame!

in the last couple of rides and races, i have noticed quite a bit more noise. have been punishing it more than in the beginning. the bikes about one year old with around 50+ hours on it. probably just now breaking it in!!

Thanks guys, it sounds like I'm just being paranoid. I got my big Moab weekend coming up over the Holiday and want to make sure the bike is in top shape.

I did just recently switch over to the Yamalube semi-synthetic engine oil about 250 miles ago after about 2000 on the regular Yamalube oil. But I doubt that would harm anything, especially going to a better oil (or is it?)


Dougie, '99 WR400

Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

just bought the semi-synthetic myself, going to change the oil this weekend.

Hey Dougie,

How are those One Industries tank graphics of yours holding up? I want to cover up my YZ tank with something. Are the gas fumes peeling off the tank graphics?

Dougie.. those measurements are fine.

Usually they tighten up if anything.



**Ride it like you Stole it!**

Matt Porritt

99 YZ400F

Rubber Chicken Racing


Those graphics have been holding up very well on the tank. No bubbling at all. they have been on since late January. I don't leave gas in the tank too long. Especially if it is going to sit more than a week.

I had to cut mine to fit the IMS YZ tank and some of the edges were coming loose after some dirty rides. I just cut the loose ends away and it looks just like new again. The shroud graphics are holding up great. Even with a few wipeout scratches on them.

I like them a lot and would recommend them if you are looking.


Dougie, '99 WR400

Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

Have any of you guys experiencing this perceived new noise replaced your clutch yet?

not yet.

I recently installed a Hinson basket, new fiber plates and new springs. Every spring in my clutch was out of tollerence after 14 months. So I guess I replaced my clutch.

However, I started noticing the increased engine noise, increased vibration at higher RPMs and stuff in the oil filter about a month before I replaced the clutch components.


[This message has been edited by Clark Mason (edited 05-19-2000).]

Did the noise go away with the clutch rebuild?

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