Valve Adjustment Interval for WR426

I downloaded a copy of the owners manual for a 2001 WR426. It listed the valve adj. interval as 600 miles. Now... I'm new to the dirt bike scene, and coming from KLR's and DR's with intervals of 6000 or 7500 miles, I just about had a heart attack. As I think about it though, 600 miles is probably close to the same interval in time if the bike is only used in the dirt and not as an all-purpose bike like my DR. Is the 600 mile adjustment interval reasonable for a dirt bike, and should I stop crying about it and just buy one?? Thanks!

I downloaded a copy of the owners manual for a 2001 WR426. It listed the valve adj. interval as 600 miles. Now... I'm new to the dirt bike scene, and coming from KLR's and DR's with intervals of 6000 or 7500 miles, I just about had a heart attack. As I think about it though, 600 miles is probably close to the same interval in time if the bike is only used in the dirt and not as an all-purpose bike like my DR. Is the 600 mile adjustment interval reasonable for a dirt bike, and should I stop crying about it and just buy one?? Thanks!

My valves have been checked twice in over 6000 miles.

1.after break in

2.when I installed an 03 YZ Auto comp. cam.

Check em and forget em....Hondas these bikes are not.

Thats just a recommended interval. A more reasonable interval is twice a year.

Thanks for the info. Makes me feel a lot better. Two inspections a year - not unreasonable.

I have yet to check mine I've had the bike since new, 04 wr450 with lots of miles and ice riding on it. What should I expect as a symptom of valves being out of spec. I thought you didn't worry about valves until it became hard to start? I know that is probably not 100% true but it's what I have been told over and over so it's all I know.

My bike runs great, starts with no issues and has plenty of power just like the day I bought it.

Why should I be checking the vales again?

I have yet to check mine I've had the bike since new, 04 wr450 with lots of miles and ice riding on it. What should I expect as a symptom of valves being out of spec. I thought you didn't worry about valves until it became hard to start? I know that is probably not 100% true but it's what I have been told over and over so it's all I know.

My bike runs great, starts with no issues and has plenty of power just like the day I bought it.

Why should I be checking the vales again?

Of course you need to check your valves.

While your at it (since it sounds like you have plenty of hours on it) change your cam chain, if you don't change the cam chain (every 100 hours) the worn chain can eat up the crank gear which is made onto the crank half. If you tear up the crank gear then you have to split the case and change out the crank half. :cheers:

Of course you need to check your valves.

While your at it (since it sounds like you have plenty of hours on it) change your cam chain, if you don't change the cam chain (every 100 hours) the worn chain can eat up the crank gear which is made onto the crank half. If you tear up the crank gear then you have to split the case and change out the crank half. :cheers:

Is everyone else changing the cam chain at 100 hours? That's not alot of riding?:p

Is everyone else changing the cam chain at 100 hours? That's not alot of riding?:cheers:

100 hours is about a years worth of riding for most people. Changing a cam chain takes 30 minutes and cost about $30 for the chain and mag cover gasket.

Your supposed to check those? J/K I know they need checking but with no signs of the valves being outta whack i never checked mine.. 4 years and going without opening up the motor. Just oil and filter changes. :cheers:

I have an 01 WR426 and have twice had an issue with the half moon valve cover gasket blowing out while riding, then spewing oil all over the macine. I had to Zip tie the half moon gasket back in during a ride last time this happended. I have to assume this because I have not been on top my valve adjustments. Has anyone this happpend? Can it be avoided with timely valve adjustments.

I have an 01 WR426 and have twice had an issue with the half moon valve cover gasket blowing out while riding, then spewing oil all over the macine. I had to Zip tie the half moon gasket back in during a ride last time this happended. I have to assume this because I have not been on top my valve adjustments. Has anyone this happpend? Can it be avoided with timely valve adjustments.

That sounds like your blow-by tube is clogged or pinched. Your building too much crankcase pressure and it has nowhere to go, so it pushes the gasket out.

Your supposed to check those? J/K I know they need checking but with no signs of the valves being outta whack i never checked mine.. 4 years and going without opening up the motor. Just oil and filter changes. :cheers:

I'm on the same plan... so far so good...just jinxed myself I'm sure of it...duh!

Where is the the blow by tube? in the crank case? Could descibe how I could check or clear it? Thanks

Where is the the blow by tube? in the crank case? Could descibe how I could check or clear it? Thanks

I comes from the valve cover and (on a WR) I believe it runs straight back to the air box. Pull it off and run some compressed air thru it.

It actually runs out of the valve cover and down the left side frame rail to where the frame curves to craddle the motor. This is on pre '03 models. I believe the '03 and later models are routed into the air box, part of the emmisions I think.

It actually runs out of the valve cover and down the left side frame rail to where the frame curves to craddle the motor. This is on pre '03 models. I believe the '03 and later models are routed into the air box, part of the emmisions I think.

That could be. Thats how its routed on my YZ. I've seen newer WR's with it routed to the box, I just figured all WR are routed that way.

if its a 426 then it comes out the valve cover down the left frame tube and around to under the cradle..

breather.jpg

Check and make sure your breather hose is not clogged. There is a breather hose running from the valve cover to the bottom of the engine. You can't miss it. It is black and probably 5/8's (or larger) in diameter.

Bob

Blow by Tube did seem to be the problem. Thanks.

I am going to plan inserting a "T" and running it into the air box the next time I get it on the stand and torn down. Does anyone have a good picture of this being done?

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