Brought the new '02 WR426 home last night

1. Pulled the backfire screen outta the air filter cage, oiled the air filter. Pitched the airbox cover.

2. Pulled tank, drained out questionable fuel. Should I remove the white antisplash insert from the fuel tank?

3. Eyeballed the carb, gonna cut/remove the throttle stop this evening.

4. Gonna drain out the green antifreeze, and replace with the non silicate orange/red stuff.

5. Anybody got starting points for the following?

Jetting for 7,000' elevation? Why different needles avail for Europe vs US.

Spring rate? I go ~230lbs. Looks like they put really stiff springs for the US bikes, any guesses whether I should get some stiffer ones on order?

Ordered a WB Vortecx? exhaust insert this am, along with a coupla extra Twin Air foam air filters.

Since tank is off, I should probably do the "Grey wire mod" Anybody got good instructions on what to do?

Thanks, Buck the "old fat A enduro rider".

PS. Yawl do remove the metal screen outta the air filter cage, right?

Not good! Put that screen back in.. Then go to history and type in grey wire..jetting.. any other questions you might have. you will get 3-days of reading on each subject. why would you remove the anti splash insert? This is the 1st time I've heard that one. the sprngs/suspension feel really stiff because A.It's all new and will break in.. B.Your too heavy for the stock springs, so you sag the springs and valving past the soft zone and into the stiffer range.

Congrats on your new bike...

SoCal

[ April 24, 2002: Message edited by: SoCalWR426 ]

Jeeze SoCal, you had me worried!

But there are at least two dummies out there.

http://www.socalmotox.com/project_bike_filter_screen.htm

I understand the Grey wire mod now, and will do it tonight before reinstalling the gas tank.

Probably hold off on the BK mod. Gonna get engine break-in done first, then start jetting it, and see where the spring rate on both ends are at after I've flogged it for a while. That way when I put new springs on I can rebuild the forks and shock at a baseline for future valving work. I'll probably go with Spectro 125/150 fork oil and Spectro UltraLight shock oil when I rebuild unless yawl have other suggestions.....

Ok SoCal, I'll probably pony up for a replacement air filter cage WITH screen.

Wonder what that little impulse last night will cost me.....

i may be a young but at 22 i have seen 2 yz400 burn up because the back fire screen was out. not good, leave that bad boy in there or your bike will be a blue puddle. the worst part is the sir filter full of air gets lit and you can put it out till you unbolt the seat, by then shes a blazin.

Probably hold off on the BK mod.

It is not that likely that the BK mod will help you much. How hot is it there now?

You should be able to roll on the throttle and have nice steady increase in revs with no stumble or hesitation. If you have a hesitation you can fix it with adjustments of the fuel screw and/or smaller pilot jet. Same with a "blip."

If you have a "bwwwwaaaaar" type of bog when you wack the throttle wide open, you may benefit from a leaner clip position on the needle or slight adjustments in the accelerator pump timing screw.

If you still have a bog or stumble after you do the above I would be surprised but would agree that you may be a candidate for the BK mod.

I've done the BK mod on bikes that had absolutely no bog or hesitation and it made them run better than you could imagine. I've also done a couple that didn't get much of an improvement. My suggestion is definitely do it to see if yours reacts favorably. Heck, its a free and easy mod.

And I think I'd shy away from the 125/150 fork oil. It'll make it harsher over sharp edged bumps. Run your oil level at about 90mm and that should help with bottoming resistance.

Yawl are GREAT!

Cut the throttle stop to 25mm OAL. Probably woulda gone to 24mm, as the slide has just a hint of hanging down at WFO. Like a 10 minute job once the tank was off.

Pulled airbox cover and exhaust insert.

Gray mod - simple to do, did it, and....

THE BEST part is my jetting is good enough to race on. I'm at 7,000' elevation ~55F and dry, just finished 15 mile easy jeep road ride, great throttle response, no bogs....

Suspect with all these mods yawl have to jet up down low?

Gonna pass on the BK mod for now.

Suspension is stiffer than heck right now, will back completely off the compression both ends for the next breakin ride, try to loosen up the stiction.

I actually don't mind the tank/seat setup right now, so I'll leave that.

Gonna run Mobil 1 15W-50 at first oil change, I'll check valves then too!

Thanks again

Mark Buckholz, happy camper

2002 WR426FP

2002 KTM380exc

2001 SkiDoo Summit 800

1993 Yamaha TDM850

PS. I'll order a new filter cage tomorrow, and not hork up the backfire screen like I did the orignal one.

PPS. The video on the Yam site allows me to start the thing in one kick. Haven't tryed starting after an upset...........

PPPS. Oh ya, the wonder state of AZ gave me a street legal liscense plate and title today when I registered the bike!

skthom2320

- My 2002 bike has this problem. These mods i did when I first got it home - took out the baffles on stock pipe, pulled the air box lid. Running

92 octane gas.

When sputtering on top or near top like that does

that normally mean a lean setting?

YOUR QUOTE:

You should be able to roll on the throttle and have nice steady increase in revs with no stumble or hesitation. If you have a hesitation you can fix it with adjustments of the fuel screw and/or smaller pilot jet. Same with a "blip."

Buck,

Great idea! Puttin that screen back in. I sure would hate to see your next post about your 6K bonfire :) . I read that thread you posted, that guy mentioned the cheap performance improvement was worth the chance.. Not me! I guess then it's not such a cheap improvement.. The 2002 models usually don't need the BK mod. But as MXTuner mentioned, it's cheap.easy, and you can put it back to stock if you don't like it. Good Luck, and Roost...BTW, Good choice on oil. I too will be going to Mobil-1 V-Twin when my supply of Golden Spectro runs out, and when I can locate a supplier for Mobile-1 V-twin..

Socal

Hey boys, just back from Co-Ed softball.... America is great, ain't it!

Wrooster, you get a big atta boy for your oil change technique and write-up. Iffn you ever wanna make implantable medical products, we sure could use you writing the SOP's/ training the folks that make the devices!

Well, got two beers in me, had a great day breaking in my new WR and whacking the softball!

What's the right time to check valves and change oil for the first time?

Ah, crap Wrooster, if we hired you, you'd probably end up as my boss.

What kinda engineer?

Pulled the antisplash insert on the old BRP (XR650R) as it made the quickfill work poorly. The Yam has the same basic setup.

So, if there is disagreement between the computer microfische and my service manual on spring rates for fork and shock, which do I believe.

Thanks.

buckholz writes:

What's the right time to check valves and change oil for the first time?

try the info here:

http://www.thumpertalk.com/bike/ubb/ultimatebb.php?ubb=get_topic&f=10&t=003892

What kinda engineer?

double, ME&EE. i like pain :*) i work for a telecom equipment company designing optical access products (GbE/10GbE & OC48/OC192/OC768 SONET/SDH DWDM ADM's).

the wrooster

Originally posted by S Phillips:

When sputtering on top or near top like that does that normally mean a lean setting?

There is a difference between a "sputtering" and a popping (sputtering seems to be rich and popping seems to be lean) :) . You may be hitting the rev limiter if you are very high up in the revs. On my bike, I have encountered a rich "sputtering" now and then. If the sputtering is at low to mid throttle (and not high revs) try one clip position leaner (move the clip up one notch) first. If it is at 1/2 throttle or higher, then go down one size on the main jet.

This carb is super easy to jet. You don't even have to take it off the bike. For needle, I just remove the carb from the air/intake boots and let it hang. Then you can get to the needle from the top (see your manual - there is an allen bolt/spring thingie that you remove then you can get to the needle/clip with tweezers. Put the needle in a sandwich baggie to remove/replace the clip (that way you don't lose it). For pilot and main, you can get to it from the 17 mm bolt on the bottom of the float bowl by just rotating the carb.

Where exactly is your stumble or hesitation? As you roll on the throttle, does it occur down low? If it is down low, then adjust your fuel screw IN until it goes away. If you get to the end of the adjustment and it still there, get a smaller pilot jet.

Hope that helps. PM me with your results and I will be happy to help.

Originally posted by SoCalWR426:

Buck,

Great idea! Puttin that screen back in. I sure would hate to see your next post about your 6K bonfire :) . I read that thread you posted, that guy mentioned the cheap performance improvement was worth the chance.. Not me! I guess then it's not such a cheap improvement.. The 2002 models usually don't need the BK mod. But as MXTuner mentioned, it's cheap.easy, and you can put it back to stock if you don't like it. Good Luck, and Roost...BTW, Good choice on oil. I too will be going to Mobil-1 V-Twin when my supply of Golden Spectro runs out, and when I can locate a supplier for Mobile-1 V-twin..

Socal

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