DT125R ARCHIVE

Firthy · DTR Senior Member

RE: Nordt`s Yamaha WR 426

NorDt · Guru

Haha, Theres a guy i know who has one of those, I think he has a black one, it used to belong to he`s father, But he`s father never used it, and didnt wanna sell it because he tought if he sold it he would be as good as a murderer because it was so dangerous to ride. I know hes son, And he takes it out for a spin every now and again.

NorDt · Guru

Would be fun asking the guy if he would be interested to sell it, Would be fun just to have such an old and big 2 stroke in your garage ^^

NorDt · Guru

btw guys, heres 2 videos i made with my WR 426, Its cold as hell in Norway now. But in my region it hasnt snowed for weeks so the roads are dry and i can ride :D

http://www.youtube.com/watch?v=Iy-de5aZu90

http://www.youtube.com/watch?v=iG-vbO-6T10

eG x LoGiKzZ · Guru

whats it like compared to the dt? much more power?

NorDt · Guru

Well yeah, With the dt i could do power wheelies in 40-50 kmh. thats about 30 mph. With this thing i do powerwheelies in 60 mph xD, with the current gearing i dont think it does much more than 60 mph tough, maybe 65-70

NorDt · Guru

is there anyone who has had a bike like mine ? Or a YZ 426 ? im interested if anyone knows of any simple mods to get some extra spark from the bike.

Ive been reading on some sites, And apperently removing a cover from the air filtre box is supposed to give a slight increase of power, but im scared this will cause too much air and eventually seize the engine because of warmth.

Also changing the valve timing to the same as the YZ 426 is supposed to give increased effect, But people are arguing if this is a plasebo effect because you shift the powerband, Or and actual power increase ^^

Ill atleast try removing the cover from the air filtre box, Because i have a suspicion that my bike is getting too much fuel to air ratio. Because it drowns if i give alot of throttle from low rpms. Maybe it will help. Ill check it out tomorrow :D

Nathlaad · DTR Legend

all i can think of with the airbox is, more air going in = better response which is why 3x3 mod is the 1st thing to do on the DRZ as the stock airbox is restrictive!

NorDt · Guru

i think it would be weird if the WR 426 would be restricted in any way.. why would it be ?

But im gonna try removing the lid of the air box and see if it makes a difference in any way, Also theres talk about removing a grey wire that does something to the ignition. But i think this is only for the US models. Im gonna go to bed now, Get up early tomorrow to spend some time in the garage with the WR, and take it for a ride to see if there is any difference.

wish me luck ! :D

NorDt · Guru

Removing the top of the air filtre box just made everything worse, So i screwed it back on, The + side is that now i know that the problem i have with it now is too much air, im not gonna do anything about it now, Later i might try adjusting the carburettor needle. i think that might be enough to fix the small problem. as you can see in the vids its not very noticable but still..

Nathlaad · DTR Legend

may sound silly but have you tried cleaning the air filter too?

NorDt · Guru

Not properly, bought some filtre cleaning fluid + proper filtre oil today so gonna do it soon

Nathlaad · DTR Legend

Good man, keep on braaaapping, us 4 stroke boyz in a league of our own aren't we ;)

NorDt · Guru

Haha, yeah. Im curious to see if changing the engine oil and cleaning and lubing up the air filtre will make any difference, because of the cold, i was told by the dealer i should use a thinner oil. So he sold me 2 litres of 5w40

Nathlaad · DTR Legend

Thinner oil, and if you're using it all winter then id jet it a little richer aswell!

NorDt · Guru

Hmm, it had a 60 jet when i bought it, 65 is stock, so i put a 65 on it, if it still doesnt behave the way i want it after lubing the filtre and changing the oil ill adjust the carb needle and if that doesnt do it il try a 70 jet perhaps

Nathlaad · DTR Legend

Also try turning adjusting the fuel screw!

NorDt · Guru

Yeah lol, altough i cant find it xD , ill check the manual when i get home

NorDt · Guru

Nath, check this out.

"The stock air filter box limits airflow to the filter. Remove the top lid from the air box to increase airflow to the carburetor. This will make your WR a bit louder but it's a necessary modification for cost free performance."

this is taken from http://www.off-road.gr/article64.html.

when i did this, it just worsened my problem with too much air. Do you think this mod + a bigger jet would give more performance ? Or not affect it at all ?

Nathlaad · DTR Legend

You will defo need to rejet if you open the airbox to flow better, im useless with carbs so youll have to ask someone who knows abit more, but as far as i know its to do with sorting the air to fuel mixture after opening up the airbox!

NorDt · Guru

yeah but will it actually give more effect is what im wondering ?, Does more fuel and air always equal more horsepower or torque ?

I guess i can give it a shot. But proboably not before summer ^^

Nathlaad · DTR Legend

wouldnt be a horsepower gain, more response off the throttle, on the DRZ its a pretty big difference but thats cus we have a Constant Velocity carb, i'm guessing the WR has a FCR carb and the DRZ's CV carb is shockingly bad! it will be worth it f you can get the jetting right!

NorDt · Guru

I dont know what you men by FCR and CV. But my carburettor is one with a Accelerator pump in it. Does your DRZ have one of those ?

Explain what CV and FCR means please ? xD

Nathlaad · DTR Legend

Nope, yours is an FCR with the pump - simplest way i can explain it really as im not a expert on carbs at all, FCR is pretty much instant throttle response (better) and the CV is smoother and more fuel efficient that about as much as i know on them haha

NorDt · Guru

Hmm, so FCR has a pump. I dont like that pump -.- because i think it might be why my bike is bogging when i pull the throttle really fast. Im not shure tough...

Nathlaad · DTR Legend

From what i've read its a 39mm Keihin carb, and i'm sure there FCR's but not 100%

http://www.thumpertalk.com/topic/72937-need-help-with-bk-mod/page__p__498857#entry498857

this may help looking at it!

NorDt · Guru

i know it has a accelerator pump

NorDt · Guru

so this guy wants me to drill a hole in my carb ? xD

Nathlaad · DTR Legend

I think thats an additional mod after opening the airbox and rejetting

NorDt · Guru

hmm okay, What pains me is that the quickshot from boysen that i bought is supposed to fix the bog i have, But it didnt, I have tried adjusting it a bit. but it still doesnt dissapear.

Ill try changing the oil, And giving the air filtre some oil, Maybe giving the air filtre oil will be enough to fix the last bit of the bog, Since the bog is there because of too much air.

If that doesnt work im gonna try adjusting the timing for the accelerator pump and the quickshot a bit more just to give it one last shot before giving that one up :P.

I cant find anywhere where the manuals says anything about the mixture screw, Maybe the FCR carbs dont have one ?.