Wr 400

I am new to this site and was wondering if anyone knows about the older wr 400's I recently got a 1998 fairly cheep i like the bike but there are some things that i want to change/ improve it seams like the carb has 10 times more hoses then it should and was wondering if this was for emmisions like the hondas did on the xr's is there a kit? Ii also want to get a different tank for the bike cause the oe one on the bike looks like it came off of a 1980's bike any help would be great thanks?

You can search around the site for "octopus", that will help you get rid of a bunch of those hoses that the early WR's had. Clarke and IMS both make aftermarket tanks, if I remember correctly you need a YZ seat to use either one.

so the seat needs to be changed too? i cant just buy a yz tank and bolt that on?

also i noticed there is a small valve on the frame with hoses that go to the carb is this part of the octopus removal they talk about? and what is it i dont have a manual yet no other 4 stroke i own has anything like that

That is the hot-start. When you pull it out, it leans out the mixture by letting air into the intake. Very useful when you stall/lay it down, or flood it. Should be a red push/pull switch.

IMS does have some WR-specific tanks for your bike. I just bought a 4.0 gal IMS that's supposed to be specific to the WR400. I've heard you can get crafty about the seat mount on the tank to use the WR seat, but I have no experience there, myself. I'm not sure anything looks that much different than stock, other than bigger and bulkier. Cover it up with stickers if you're unhappy with it. :busted:


thanks for all the input guys I'm pry going to get an ims tank just cause most all my bikes have had one and i was kinda thinking that valve was for hot start but wasnt too sure cause i have no manual and theres no knob on the valve just a metal stem guess it broke off anyway thanks again

Pay close attention to the instructions if you decide to "De-octopuss." You need to seal everything properly and then you will have to change air pilot jets.

I have a '98 that I ride regularly throughout the year (except winter), the valve with the all of the hoses is the air cut-off valve. This valve enrichens the idle circuit when you snap the throttle shut on decel. The other item on the frame was properly described as the Hot Start and usually has a knob.

You don't want to remove the hot start and, jetted properly, you don't need to de-octopuss.

If you go to the beginning of the WR forum and follow the update forums you can go from mild to wild for little or no money.

Assuming nothings been done, do the following.


Change the exhaust baffle.

Clean carb and re jet. (pay close attention to the accelerator pump diaphram and rod)

YZ time (either re-time stock cam or replace with later model)

This will improve starting and performance.


Spring for you weight.

Rebuild - revalve.

Set the sag properly.

Expensive (maybe more than the bike is worth), but makes night/day difference.

For you butt:

New seat foam

Nothing more to say there.

I've owned mine for 5 years and have done all of the above, plus a few others. I can't replace it because it will cost too much to set up a new bike.

By the way I rode an '07 KTM 450 xc-w (I know I'll get some crap for this) and it was nice, but it wasn't faster and the suspension (stock) was harsher on little bumps.

Final word related to all above, there's no substitute for proper set-up.

Yea i had an 07 300 xcw for a while but got rid of it cause i never rode much due to work i also had a kx 450 and a crf450 but both of those 4 strokes for me were just too time consuming on maintinance since i only took them to the track the bike i have now 98 wr 400 i got for 1200$ it needs some cosmetics but it runs great starts in one kick the guy told me he went through the bike and changed the cams to cams out of an 07 450 quad? i think is what he said so its supose to have the auto decompression is what he was telling me and it also has a wr muffler off an 07 but with the oe header witch i dont like cause as youguys obviusly know you have to loosen it to change the oil filter but alot of things were reused for no reason like number plates were repaired and painted to look new as well as hand guards thats just dumb so those are going in the trash as well as the tweeked and untweeked handle bars but i like the bike it runs like a top good power so i cant complian about the little things like that

so can i use any yz tank or does it have to be for the yzf400 only? and what other years work and do i need the same year seat?

The YZ tank and seat go together and are different than the WR.

Yea i kinda thought so but do i need to find a tank and seat for a yz 400 or do other models works too? like a yz 250 from same area?

go to www.ronayers.com and look up your stock tank ,then check the pt number of a genuine yz tank on the same site.I have a clarke tank (13.4 litre)on a wr400 y2k .no seat required .choice of 1 or 2 taps also

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