426 has arrived, questions for thumper veterans !!!

Hello all,

I am new to this forum, and am very impressed. I was a roadracer (zx7 superbike) but went to dirt about 4 years ago. Since then I have had 97 yz250, 00 yz250 (for sale) and am now the proud owner of a 02 yz426f. Obviously I have experience with four strokes from my roadracing days, but still would like to ask the thumper veterans some generic questions. Since the 426 does not have degreeable cams (i hate degreeing cams :) ), I will do all of the work myself.

Oil preference?

How often do you check/adjust your valves?

How often do you change your oil/filter?

Any "tricks of the trade" when changing the oil?

Position of compression release (above/below clutch lever)?

Thanks in advance for the advice ,


Oil preference?

15/50 Mobil 1 Red Cap

How often do you check/adjust your valves?

couple times a year depending on use.

How often do you change your oil/filter?

Every few rides. You can clean the filter.

Any "tricks of the trade" when changing the oil?

You need two drain pans. On for motor and one for the resevior.

Position of compression release (above/below clutch lever)? I like above. But, this is a personnal thing.

Being an ex-roadracer, you'll probably be banging the downshifts, and using the engine braking. Be careful, because the 400/426's don't have the strongest shiftforks. Full on upshifts or power downshifts will wreak havoc on the engine.

As far as oil/filters, the trick setup is using the stainless steel Scott's oil filter. Re-usable, cleanable.

You can degree the cams, but you need to press yours off, and re-press them at the "right" angles. There is a bunch of power to be had in degreeing (you should know), even setting it to true stock numbers will help.

Oh yeh, with the compression release, if it's on the bottom, watch out you don't knee it when you scoot up front...

thanks for all of the great info, i really appreciate it.

- charles

One more thing about the oil change - when draining from the frame be careful and use a cutout milk carton (or funnel) to catch/stop the oil from getting all over your front wheel. The oil will spurt out quite a ways!

If you want a magnetic oil drain plug, I made one by using the "rare earth magnet from Radioshack" tip I gleaned from the board. Go to Radioshack and buy a $1.50 pack of rare earth magnets (about 3 mm in diameter; strong little buggers), then JB weld one of them onto your drain plug! Voila.


Steve T

Welcome Charles.

>Oil preference?

This one is highly debatable, but you can do a search and see all the different opinions.

>How often do you check/adjust your valves?

I have checked mine on my '00 3 times since new and still right on spec. Probably have done it about every 25-30 hours or so.

>How often do you change your oil/filter?

At first I cleaned my filter every oil change since you will be getting lots of crud out of it. Now after two full seasons of racing and riding I have found that I only need to clean it every 3rd oil change, if that often. I change my oil every second race which is maybe 1 1/2 - 2 hours.

>Any "tricks of the trade" when changing the oil?

The main thing is to warm it up real well to get all the cruddies suspended in the oil and drain it as soon as you shut it off. I like to run it through all the gears several times then while it is draining I'll slowly crank the starter to get all the oil out of the plumging.

Position of compression release (above/below clutch lever)?

I like mine above, I would have it broken off by now if it were below. Finding it is automatic there too.

Also there is a screen in the bottom of the frame reservoir but I've had mine off twice and have never even found a fleck of anything in there, but you should check occasionally since others have reported theirs being dirty.

Good luck...


[ October 31, 2001: Message edited by: MikeOK ]

I've got the '01 and I've been changing the oil every 3 rides or so. The first few changes the filter was full of metal with every change, but lately it's been pretty clean and I'm only checking it every other change. I just clean and reuse the stock filter and use Spectro synthetic blend oil. I haven't checked the valves yet but it's on my todo list for the very near future.

thanks again for the info !!!

-- Charles

One more note regarding oil change tricks of the trade. When reinstalling the bottom bolt of the oil filter cover, be sure to clean the metal shavings out of the bolt hole to prevent damaging the threads. There is a port that allows oil/metal to drain into the bolt hole. The port is visible when the cover is off (look below the filter and just above the bolt hole). I have no idea what purpose the port serves and have heard of some people actually plugging it. I am hesitant to do so without knowing its purpose so I just clean the threads during every oil change.

[ November 01, 2001: Message edited by: bassr #186 ]

If I remember correctly the manual mentions that he hole is to provide an oil drain for the compartment which holds the oil filter (take out one screw to drain the filter). I don't remember what page I read this on.

I moved my compression release to the throttle side......it works awesome. It makes it way easier to start in gear, it's much nicer for bump starting and it also keeps my grabby hand off of the throttle when starting.

DO NOT USE A FULL SYNTHETIC OIL IN A MOTORCYCLE. Full synthetic is to slippery for the clutch plates . Ive been using 10W50 semi synthetic Yamalube oil. My oil change , about every 3 rides or 10 hours . My shop stated that the valves are very rarely out of adjustment, maybe after a couple years/ summers, the valve faces will cup alittle and need a diff shim. I love the power the bike produces and it goes wherever you point it with athority. My stock chain didnt last long and was out of adjustment every other ride.A "Regina X ring chain fixed that.Front forks were very harsh for the first couple weekends then they broke in and soak up even the nastiest braking and acceleration bumps.

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