yz 426 problems

[gaz1985]

hi everyone im new to the site and 4 strokes

i have just swapped my cr125 for a yz 426 2002 i went on it for the first time today and its hard lol

firstly everytime i get into a corner it stalls it also struggles when setting off really jerky its so frustrating i have a 48 tooth rear sprocket would a 52 help

also the suspension bottoms out quite bad

please help

 

[Jaybird]

I found I needed a different line than what I would have taken on a 125. A more relaxed attitude, if you will.

Having the suspension set correctly may be the only thing you need though.
You may also look into an auto-decompression cam to replace your existing exhaust cam.
It will make the starting much easier, and the stalling much, much less. Stalling with the auto decomp cam in place allows you to simply "bump" start the bike as you would a 2T, as long as you have some momentum still applying.

 

[gaz1985]

to be honest its not the starting thats the problem i just wish it wouldnt stall on me

does anyone know any mods etc to stop the stalling

 

[Jaybird]

rekluse

 

[BSWIFT]

rekluse

X2

 

[gaz1985]

whats

reklus

cheers gaz

 

[Jaybird]

+e, it's another answer you your question.

Try a search engine. Preferably 4T.

 

[OldMaiconut]

One other thing to check before going with a Rekluse Auto clutch is your idle speed. I have a YZ426, and had the same problems riding it in the woods. I went to a 50 rear sprocket up from the stock 48. I think your problems are mainly self-induced. You can't ride it like a two stroke. You need to keep on the gas a bit in the corners, even if only a little. That keeps the front end planted better. The idle speed sounds fast for most coming off two strokes, where you set them so they won't idle by themselves. The high idle helps with throttle response off the bottom, and will cut down on the stalling. I still have my 426, but ride it on tracks only. I have the Rekluse on my woods set-up YZ250.

 

[gaz1985]

it has a 48 on the back but ive just got a 52 as its a very tight track where i ride hopefully this
will help

 

[Cheater]

I have a friend with a 426, he has nothing but problems with it. Can't keep it running, and it is a pain in the butt to start. He put a new cam in it, to help but I still see him on the side of the track trying to kick the bike over. My advice to you is to trade it in for a 450f.

 

[gaz1985]

it starts easier than any bike ive had once you get the technique right i must say i enjoyed riding it but its just the stalling i need to conquer

 

[BSWIFT]

Oldmaiconut gives solid advice. I bought a 426 and suffered the same issues coming off of a 2 stroke. The Rekluse is a pricey fix but it really works. A 52 tooth rear sproket seems a bit low for a track, even a tight one. Increase your idle speed and tune to get your best throttle response off idle. Learning to hold a small amount of throttle in the corners is just a technique that takes effort. '
IMO, the 426 pulls harder than the 450's. Having owned both, the 450 was more forgiving but still a handful for me @ 150 lbs. I put the Rekluse on my 450 to ride trails. The ability to lift the front wheel in any gear at any speed was amazing but the overall power and weight of the bike wore me out. The exhaust cam mod is great if you are having problems starting the bike but not a "have to" mod, only a $100 or so to do it. It only slightly reduces engine breaking(barely noticable) but makes starting simple. The 426 is a power house bike that some people will never get used to, not impossible but not a simple switch.
Best advice is to tune and practice your technique. You'll enjoy the bike.

 

[gaz1985]

what sprocket set up would you recommend it currently has a 14 front 48 rear

thanks

 

[flynbryan]

Add 1 to 2 more teeth on the rear if you have your heart set on it. It really sounds more like you need to ride the machine more and get used to how the power comes on. I too found when I switched from Yz125's to a Crf450 that I had to do like others have mentioned about not shutting down the throttle completely. Work the clutch and keep the idle high till you get used to the new bike. Throwing parts at it right off the bat is not always the answer.

 

[Matt90GT]

Okay some background on the 426F bikes. Each year was a learning experience from yamaha. They have the FCR2 carb, but there is no leak jet in the bowl. They also do NOT have the autodecompressor exhaust cam.

Here is some mods you need to do to the bike:

-install a yz450F exhaust cam. That will give you autodecomp system and make kicking the bike easier. - no starting drill

-you are going to have to jet the bike. period. Yamaha got close with the 02 model, but it is going to take some time and money. do a google search for the BK mod to the 426 bike. You have to time and modify the accelerator pump in the bike. You will also need an extended fuel screw so you can adjust it easily. Last thing is to get a JD Jetting kit. Those 3 things will make the carb run without hesitation and almost like EFI when you get it dialed in.

-suspension is dated. You can either swap some 05+ KYB twinchambers on the bike with new triple clamps. Probably the best thing you can do! Short of doing that, revalve the suspension front and rear. I ran the Racetech Gold valves front and rear in my old 426 and made a world of difference. Took a couple of times to get the front shim stack where I liked it.

-last thing is with all the older YZs when you remove the manual decompressor from the head (with the install of the 450 cam), you need to buy an aftermarket plug for the head. The stock caps tend to fall out.

 

[riot983]

Same problem here switched from my 125L and im stalling alot. Im just goin to get a new rear sproket till I learn