YZ426F Hard Starting

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YZ426F Hard Starting

Postby 4Strokes » Sat May 21, 2016 12:07 pm

Topic: yz426f starting
Author: atyrrell
Posted: 04/29/2006 3:28:08 PM

we just bought a yz250f and a yz426f. the 250 starts up very easily and has a bbr kickstarter which is 1 inch shorter then the stock. the 426 is difficult to start. would replacing the stock with the bbr kickstarter make much of a difference?

Reply by b_king on 04/29/2006 3:49:50 PM
It may help you get more power out of your kick, but other than that it will do nothing mechanically. When you say difficult to start do you mean the kickstarter is stiff? Or it doesn't want to run? It may just have a higher compression and larger bore piston in it which would be more difficult to kick over. Good luck!

Reply by atyrrell on 04/29/2006 6:46:11 PM
Thanks. I think myabe we are just not used to starting such a big engine. Maybe the shorter kickstarter would be a great help.

Reply by Wild Bill on 04/29/2006 10:49:55 PM
The 450 exhaust cam swap, either a Yamaha cam or from Hot Cams will give the 426 easy starting. I did the 450DCM (decompression cam modification) in July 2003 and it paid off for me. Best money I ever spent. No more compression release or drill. Better power spread to boot. I have had no valve problems whatsoever since doing this mod. Let me know if you want some helpful links that walk you through the procedure (its simple)or some help if you do the swap. I paid 125.00 for my Yamaha Ex cam, installation was simple. Have some shims or a complete shim kit available if you do a cam swap. Bill

Reply by atyrrell on 04/30/2006 1:00:27 PM
thanks for the advice. Do u think that my dad and I, having limmited knowledge, would be able to do that? We do have a shop manual. If so do u think you could send us the information on how to do it? Thankyou

Reply by YZF426oz on 05/02/2006 02:59:27 AM
Hmm, dunno about doing the swap yorself, unless you have a fair bit of experience with motors... It can be tricky.

Starting the 426:

  1. hold decompression lever in. Push kickstart all the way down.
  2. release decomp lever, allow kick start to move upwards. It should make a clicking noise as it comes up.
  3. push kickstart down (it will travel a little less each time) until you have the motor at TDC (top dead center). this will take 2 or 3 pushes on the kickstart.
  4. With the motor at TDC, the kickstart will sit straight up, and be almost impossible to kick or even to push back down. Don't try to kick yet, you will only hurt yourself.
  5. Ok, the fun part. pull in the decomp lever - advance the kickstart 1/4 to 1/2 inch ONLY. Release decomp lever and KICK!
If you follow this cycle, the bike should start first or second kick each time. Also remember to use choke if cold or hotstart if warm. Don't be tempted to give up! Also, remember - don't bhe tempted to twist the throttle while kicking it! you will only flood it! I can't stress that enough. Keep that hand off the throttle! Even once it lights up be careful with giving it too much fuel early on.

It seems like a pain, but after a bit of practice, you do it without even thinking.

Also, If you flood the carby with fuel, it can be very hard to start. Try this -
turn fuel off, lean bike over to left to allow carby to drain. Stand the bike up, pull the hotstart knob to ON, start kicking as per the steps above. About 5-7 kicks later, it should light up. Push in the hotstart knob, turn fuel on and go have some fun! (after a while of kicking it, if it doesn't start, you may have flooded the carby.) I hope this has helped

Reply by Wild Bill on 05/03/2006 7:43:35 PM
The swap is pretty straight forward. if you can do a valve shim clearance check (Valve lash) as shown in the manual you can probably do the 450DCM, try this link and see if it is clear enough. It contains pictures that will show the proper cam timing alignment and tips on the swap. I used this to do my swap and I talked with Satch0992 in doing the swap.

I tried to find a link within 4Strokes.com but was unsucessful. Admin if you know the link here please post it and I'll bookmark it and post it at ATM also for the knowledge base there.

If you need any thing as far as help you can email me, I'll be glad to help out. This forum has helped me so much I'd like to return some of the help to others here. Bill

Reply by LtDan on 05/12/2006 2:52:39 PM
YZF426oz, Thanks for the starting instructions! I just picked up a YZ 250F, my 1st 4-stroke, and was having a heck of a time. I tried your instructions for the 426 on it and it works like a dream, every time. Thanks!

Reply by DeltaTac4 on 05/24/2006 2:02:18 PM
Well, I just got an '01 YZ426F too...with my dad. I am having a pain in the ass getting it started right now, even with all the tips. Should I check my spark plug? What else should I check? I'm kind of new to dirtbikes...and any help is appreciated. Yesterday, I was starting it on the 3rd/4th kick, but today I'm getting absolutely nothing. It sounds like it doesn't even want to start...

Reply by Wild Bill on 05/27/2006 7:59:43 PM
DT4, If you don't know the last time the valve lash was checked do a clearance check and clean out the carb thoroughly. When the YZF bikes get hard to start the valve clearance is often the culprit. Second to try and to do anyway while doing maintenance is to clean the carb jets and orifices completely. Just do not tamper with the yellow painted screws (Torx screws at the carb body halves)no matter what. Sudco wont sell the neophrene gasket and a new carb depending on the year model is from $750.00 -$1000.00, maybe less on ebay. Just a heads up from a long time 426 owner. Bill

Reply by Ragdoll MX on 06/14/2006 01:49:47 AM
here is another peice of advice on that 426.... if it is hard starting, like mine was. i would turn off the fuel, lean the bike to one side (lay it on the ground) let the carb drain, stand up, turn on furl, hold de comp lever kick about 5 times, and on the final kick (this is where it gets tricky....) release the lever about mid kick, it should fire up....it is all about how tempermental your bike is.

Reply by silverbullet on 06/15/2006 07:34:47 AM
This is my first post here on the 4Strokes.com forum, I hope to learn alot on here. I recently bought a 2002 YZ426F but havn't ridden it yet due to just having knee surgery from a crotch rocket accident but I have been starting it and letting it run a bit here and there. To start mine I turn on gas, pull choke out, push kick start down until it is at top then lightly pull decompression lever and drop kickstart down just a nick then let up on the kickstart to bring back to top and give it a full kick, do this each time until it starts. DO NOT GIVE IT ANY GAS. let it idle until it starts popping and you can feel the radiator cap getting warm/hot then push the choke in and go riding. I plan on doing the auto decompression cam swap but probably won't do it until this winter so the bike won't be torn apart during the summer.

Reply by Wild Bill on 06/15/2006 7:58:54 PM
Silver Bullet, Welcome to the greatest all round 4 stroke site. You got a sweet bike from looking at the pictures in your other post. Sounds like you have the "Drill" down pat. The 426 is one reliable and strong bike. Just keep her serviced and watch the valve lash. Roost on and enjoy. Bill

Reply by ashtong63 on 06/21/2006 2:56:58 PM
Kick the lever slowly until you hit the compression stroke. (the lever is in it's hardest-to-move position.) Pull in the compression release, and kick the lever slowly 3-4 inches. This gets it just past TDC. Now, let go of the compression release, let the lever come back up, and kick as hard as you can. NO GAS! Mine starts 1st or 2nd kick every time. If kicking over isn't the problem, check the pilot jet. It may be partially clogged, or just too lean. This would greatly effect the starting.

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