Newbie Yamaha YZ400F help


22 replies to this topic
  • regenold1300

Posted April 17, 2012 - 05:56 AM

#1

Hello, Im hoping someone can help me with a problem ive got with my new bike.


I recently bought a 1999/2000 YAMAHA YZ400F. The chap I brought it off explained the starting procedure and started the bike in front of me, on two seperate occasions from cold. It started on the first kick. Since getting the bike home I cant start it. I have tried and tried but its like its impossible to kick, sometimes you can stand on the kick start with your full weight and it wont move, other times you release the pressure off it and it then kicks but nowhere near enough to start it. I have tried using the decomp lever but it doesnt seem to make much difference.

I tried bump starting it in 2nd but the back wheel just skids along. I ended up towing it with a car to get it started.

Surely it cant be normal for a bike to be this hard to kick start?! I have read that they are tough to start but this is rediculous. I cant even kick it unless its leant against a wall so how on earth I am meant to start it in a field with muddy boots on I dont know?! I havent road bikes for years but im a healthy 28 year old so should be able to kick a bike.


Any help would be much apreciated! many thanks

heres a link to some pics in case that will help
http://s268.photobuc....dowmgf/yz400f/

  • Fade

Posted April 17, 2012 - 06:07 AM

#2

ummm....check to see if the kickstart lever is in a bind...it might just be a high compression bike and no matter how healthy you are when you go to jump on a bike that you are not used to, you just cant do it. It seems like something is wrong internally in the engine, but I wanted to get the easiest out of the way first. When I bought my 250, the guy started it first kick (cold, I thought), then killed it, and then I started it first kick. When I got it home though, it took me about 100 kicks to start (ridiculous, I know). Turns out the valves were way out of spec, and I fixed them and it starts quickly now. But, the reason i dont THINK it's your valves is because I actually GAINED compression, and you seem to have enough already. Maybe some of the bearings internally? I would say get a friend that rides alot, and get them to kick it to see if it's just you. If not, they might have ridden enough to know what the problem is. Oh, BTW: bump start in 3rd or 4th.

  • johnnyboy

Posted April 17, 2012 - 06:16 AM

#3

You must use the decompressor to get the piston just past TDC then without touching the throttle a nice healthy full kick will have it purring like a kitten ! it take time to master it but once you have it right it all becomes second nature.
Failing this maybe a latter model exhaust cam with a auto decomp will drop straight in , I know the 250s interchange but have never had the pleasure of working on the 400

  • regenold1300

Posted April 17, 2012 - 06:26 AM

#4

Thanks for the replies, The chap I bought it off is going to come over on thursday to help me with starting it. It does seem like theres something wrong though, It cant see how its normal to have a bike thats so hard to kick. Theres a chap locally who rides a few motocross bikes so ill see if he thinks its normal.

  • regenold1300

Posted April 17, 2012 - 06:56 AM

#5

Oh, BTW: bump start in 3rd or 4th.


I have tried that but the back wheel tends to still lock up, unless theres a lot more weight on it, I had to jump and and down a lot to get it to start turning but by then im at the bottom of the hill! I dont think the engines seized as once starting it runs fine with plenty of power in all gears.

  • regenold1300

Posted April 17, 2012 - 07:22 AM

#6

ave just seen this video and that makes me think there is definately something wrong with my bike. The way it moves when he is using the decompression lever is nothing like mine. mine wont move even with my body weight on it.

Edited by regenold1300, April 17, 2012 - 07:23 AM.


  • Michael Scott_119664

Posted April 17, 2012 - 07:49 AM

#7

my story goes with my dad an i have been on bikes forever i was like 5 when i started we have always had 2t but a couple months ago my dad bought a 2000 yz426f an holy sh@t i thought the same thing at first it took like 1000 kicks to get it going but now only 1 or 3 lol. i found when u go to bump start it u can do it wit 2 guy leave it in nuetral start running grab ur comp. release slam it in first note i said first hop on an dump comp relase she will fire up. also kickin it is a bitch my foot stayd soar for like 3 weeks if u pay with the kicker u will feel it out kick easy until it stops this is tdc pull comp release very gently move it past tdc 1 click ill call it let go comp. release let kicker up now jump up an put all ur weight on kicker its a kind of all or nothing thing after u get it style down it gets easyer it took me a while still an its still a b!t@h but hey its fun when it running hope this helps im stil a noob my self at these things i love my yz250 its way easyer to start

  • moto_rider7755

Posted April 17, 2012 - 10:20 AM

#8

Those bikes are tricky to start if you havent done it. I had a 1999 YZ400 and just sold a 2001 WR426. Most likely, there is something wrong with the decompression lever or you are not starting it correctly. Im going to guess the latter. Push the kickstarter slowly until you cant push anymore (TDC), pull the decompression lever, and slowly push through the cycle. Release the decomp lever and kick the hell out of it. Never hit the throttle during the process. I did find that sometimes it helps to prime the bike with 1 or 2 half throttle blips before you try to start it. If you try to bump start it, you will need to use 2nd or 3rd gear and hold both the clutch and decomp lever. Release the clutch first...a second later, release the decomp...it should fire. Neither of mine ever failed to start with bump starting.

  • DGXR

Posted April 17, 2012 - 12:23 PM

#9

The chap I brought it off explained the starting procedure and started the bike in front of me, on two seperate occasions from cold. It started on the first kick.

I have tried using the decomp lever but it doesnt seem to make much difference.


If the seller started it cold on the first kick more than once, I really don't think there is anything terribly wrong with the bike. The decompression lever is key to easily starting a 4-stroke, especially on a high-compression motor like your 400F. That video in post #6 is unnecessarily complex, plus he said nothing about cold starts. Do a search on this website for "starting procedure" or similar and you will get all the info you need. Good luck and remember this is supposed to be fun!

  • joelberg

Posted April 17, 2012 - 01:14 PM

#10

Just don't flood it! Then you'll really be hating yourself for buying a 4 stroke! :thumbsup:

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  • grayracer513

Posted April 17, 2012 - 06:27 PM

#11

This is how it's done:

http://www.yamaha-mo...troke_vid_a.mpg

http://www.yamaha-mo...troke_vid_b.mpg

  • Octanee

Posted April 17, 2012 - 08:59 PM

#12

so far whats working for me on the 426 i got here, after feeling like a idiot who couldnt start the bike, hehe,

but push down crank lever till hard or can basically stand on it, then pull in decomp lever and slightly push down enough that you feel it go down 1 "position" like it moves down a inch or 2 (the kick starter), now lift your leg up so kick starter goes to where you WANT IT for your optimal kicking power and stroke, you need to kick hard and have a long kick too, so once your ready to kick, DONT USE decomp lever, and just kick that bugger, if she dont start, re-start the process until it starts, so far its been working like a charm for me (that method),

this is also the video i have seen and been using that method which would be probably the rigght method that yamaha says to do....

Edited by Octanee, April 17, 2012 - 09:00 PM.


  • CRF100biker

Posted April 19, 2012 - 04:26 PM

#13

for a cold start...

make sure bike has gas and turn it on
pull out the choke
push on the kick starter until it stops due to engine compression
pull the decompression lever and push the starter lever about 30 degrees down
release the decompression lever and let the starter lever return to its resting position
give it a good, swift whack! follow through completely with your kick and wear mx boots when starting your bike!

i disagree with using throttle or having to use throttle to get the bike started easily. in fact, so does yamaha. the owners manual states not to use any throttle when starting the bike as it will flood the engien and increases the chance of the lever kicking back. if the bike is jetted properly then it should start easily under almost any conditions. i can get my manual decompression bike fired up faster than some riders on their auto decompression bikes.

Edited by CRF100biker, April 19, 2012 - 04:27 PM.


  • grayracer513

Posted April 19, 2012 - 06:24 PM

#14

i disagree with using throttle or having to use throttle to get the bike started easily. in fact, so does yamaha.


Yamaha does not.

Please note that the video I posted featuring Doug Dubach (who knows more about it than either of us) is posted on the Yamaha web site, and recommends priming the engine with a twist or two when it's cold. Once you learn your particular bike's nature, you'll be able to tell better about when and how much to do that.

  • CRF100biker

Posted April 21, 2012 - 08:03 AM

#15

my user manual warns of flooding the engine if the throttle is used. my bike starts fine with no throttle. if i do twist the throttle to prime the engine the starter lever usually kicks back pretty violently at me.

Edited by CRF100biker, April 21, 2012 - 08:03 AM.


  • grayracer513

Posted April 21, 2012 - 09:05 AM

#16

So does mine. But if you don't prime the engine on mine when it's cold, you may need to pack a lunch or bring a friend to take over when you get tired of kicking.

Watch the video. Notice that the throttle is NOT being opened while cranking the engine. Only to prime it. Kicking with the throttle opened is what leads to kickback.

  • Michael Scott_119664

Posted April 21, 2012 - 10:40 AM

#17

i do not wish to burst bubbles or anger any1 but crf100 guy we are talking about a higher compression insanly torquie yamaha 426 not my 2yr olds crf100 (honda) your owners manual is as helpful as helpful as my leafblowers u guys can argue all day but my leaf blowers manual says to press the prim button 3~6 times!!! but anyway ive rode alot of bikes as many other have also an learning ur bike is the best method ive been on two identicaly stock bikes an they both needed to be started simalar but also very diffent. good luck man them 426 will really throw you off with a good kick back lol ive been there as have others..... also a very violant 100 kick back???

  • CRF100biker

Posted April 21, 2012 - 01:04 PM

#18

So does mine. But if you don't prime the engine on mine when it's cold, you may need to pack a lunch or bring a friend to take over when you get tired of kicking.

Watch the video. Notice that the throttle is NOT being opened while cranking the engine. Only to prime it. Kicking with the throttle opened is what leads to kickback.


even giving it a quick twist before kicking causes kick back on my bike. it starts by at least the 4th kick when cold, usually the 2nd though. just the other day i was trying to start my bike in shoes (dumb idea people) and the kick back put a hole right through my shoe. i'm not sure what adjustments you've made to your bike. i'm using all the stock settings as laid out by the manual and the bike couldn't be any easier to live with.

i do not wish to burst bubbles or anger any1 but crf100 guy we are talking about a higher compression insanly torquie yamaha 426 not my 2yr olds crf100 (honda) your owners manual is as helpful as helpful as my leafblowers u guys can argue all day but my leaf blowers manual says to press the prim button 3~6 times!!! but anyway ive rode alot of bikes as many other have also an learning ur bike is the best method ive been on two identicaly stock bikes an they both needed to be started simalar but also very diffent. good luck man them 426 will really throw you off with a good kick back lol ive been there as have others..... also a very violant 100 kick back???


i made this username 7 years ago when i was around 12 years old. of course i wasn't riding a yz400f then (although i moved up to the 400 a year later when i was 13 years old) . you really think i'm riding a crf100 presently if i'm posting in the yz400f forum? and the factory service manual that yamaha included with the bike including instructions on how to tear the bike down to every nut and bolt if you so chose is useless? the engineers who put the information in that manual are making the big bucks for a reason. they really know what they're talking about. i'll always trust the people who designed and built the machine on what to do with it.

Edited by grayracer513, April 21, 2012 - 01:46 PM.
inflamatory


  • grayracer513

Posted April 21, 2012 - 01:45 PM

#19

i do not wish to burst bubbles or anger any1 but crf100 guy we are talking about a higher compression insanly torquie yamaha 426 not my 2yr olds crf100 (honda)


From reading his post, it would seem he's talking about a YZ4**F of one kind or other, and not a CRF100. If you came here to throw stones, you need to move along. BTW, your leaf blower is a 2-stroke with "pumper" carb, and has nothing at all to do with a YZF.

even giving it a quick twist before kicking causes kick back on my bike. it starts by at least the 4th kick when cold, usually the 2nd though.

....the engineers who put the information in that manual are making the big bucks for a reason. they really know what they're talking about. i'll always trust the people who designed and built the machine on what to do with it.


Engineers do not write or proof read manuals, which is why it still says you should lap valves when you replace them (follow that advice only if you love throwing $400 in the trash).

Out of all the YZ426's, 450's, and 250F's I've owned and worked on, none has behaved as you describe. The most mine takes to cold start is 3 in cold weather; one is normal. But that's OK. Every bike is a little different, but there are things that do work for most of them. This is one of those things.

You're swimming upstream on this one. In case you weren't aware of it, the gentleman in the video who is recommending priming the engine when cold worked for Yamaha as a test and development rider for over 22 years, probably long before you started riding, and was in on the development phase of each the YZ400, 426, 250F, and 450. He's had 4 World 4-stroke championships, 15 National Vet Championships, a couple of Loretta Lynn championships, and a SX main event win to his credit, all on Yamaha four strokes. (He even raced a YZ250F in 2000, before they were released, in the big bike class so no one would know it was a 250). If you don't want to take my word for it regarding starting, fine. You don't know me outside this forum. But you won't get much credence by proposing to know more about it than Doug Dubach.

You are correct about the dangers of starting in sneakers, though. Most of the time it's fine, because they do start up pretty easily. But there's that once in a while thing that happens, and they can kick so hard that they'll nearly break you foot right though a riding boot. Not kidding. My '03 did that once in an odd circumstance, and bent the steel shank in one of my Alpinestars. I shudder to think what would have happened wearing my regular shoes.

  • CRF100biker

Posted April 22, 2012 - 12:27 AM

#20

eh, then i get really lucky with my particular bike then. the only reason i keep it is because it is so trouble free. were it to have the typical 4-stroke troubles i'd have stopped riding it long ago and picked up a smoker.

i know who dubach is, but i also think that if one were to use the stock settings laid out in the manual and have their bikes jetted correctly their bikes would be just as trouble free.

Edited by CRF100biker, April 22, 2012 - 12:29 AM.






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