New WR400F owner with a few simple questions


32 replies to this topic
  • ian505050

Posted March 07, 2013 - 12:33 PM

#1

Hi, i have just purchased a WR400F to replace my WR250F and i have a few questions.

I have used they search engine but could not find an answer to my questions.

What are these knobs for?

I assume the lowest one is to adjust the idle and one of the other 2 is to turn on the choke, but what is the other one for?

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Also, what is this? It is activated by w lever on the handle bars?

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I really could do with a link to the workshop manual for my WR400F 2000 Plate, if anybody could be kind enough to provide me with a link?

My final question would be on starting the bike. My WR250 can easily be kick started and requires little force but the WR400 seems to be very difficult sometimes when applying force to the kickstart i feel quite a bit of resistance. Can anybody provide me with a procedure to kick start the bike from cold?

Here is a snap of the wr400 in bits well i get it serviced

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A quick snap of having fun on the WR250

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A quick snap after having too much fun

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Many Thanks Ian.

  • Krannie McKranface

Posted March 07, 2013 - 01:32 PM

#2

Choke
Hot Start
Idle

Don't know what's on your bars. Probably a compression release.

  • ian505050

Posted March 07, 2013 - 01:39 PM

#3

Choke
Hot Start
Idle

Don't know what's on your bars. Probably a compression release.


ok thanks, are you 100% sure?

On the wr250 the hot start is the little lever on the handlebars, but not sure what it does on the wr400

  • Krannie McKranface

Posted March 07, 2013 - 02:54 PM

#4

ok thanks, are you 100% sure?

On the wr250 the hot start is the little lever on the handlebars, but not sure what it does on the wr400


It's choke
Automatic Coast Valve with Hot Start system added to it
Idle knob.

Follow the cable on the bar lever, and see where it goes.
It probably goes to the cylinder, which means compression release.

You can get all this info on Google search.

http://www.frankmxpa.../-Yamaha-WR400F

http://www.motorspor...400ds/index.htm

Edited by Krannie, March 07, 2013 - 02:58 PM.


  • Thommo_400f

Posted March 07, 2013 - 03:52 PM

#5

Lever on handlebars is Decompression. You need to use it or you will break your ankle or stuff your kickstart shaft.

Starting method is VERY specific, you can't just slam down the kick start any old time.


1. Ease kickstart down until you feel compression
2. Pull decompression lever on handlebars
3. Only move kick start 1 inch further and then let it return back to top and release decomp lever (you are trying to move the piston to top of cylinder on compression stroke so it gets full cycle on your kick before hitting compression again)
At this point you are ready to kick it....the other steps are positioning your piston.
4. KICK HARD but....DO NOT TURN THROTTLE or it will squirt fuel in from accelerator pump and flood or cause kick-back.

If it is still hard to start after following these instructions, let us know, often the pilot circuit needs some fine tuning.

You will love the 400 compared to the 250
PM me about manuals if you want.

  • MANIAC998

Posted March 08, 2013 - 04:02 AM

#6

Lever on handlebars is Decompression. You need to use it or you will break your ankle or stuff your kickstart shaft.

Starting method is VERY specific, you can't just slam down the kick start any old time.

1. Ease kickstart down until you feel compression
2. Pull decompression lever on handlebars
3. Only move kick start 1 inch further and then let it return back to top and release decomp lever (you are trying to move the piston to top of cylinder on compression stroke so it gets full cycle on your kick before hitting compression again)
At this point you are ready to kick it....the other steps are positioning your piston.
4. KICK HARD but....DO NOT TURN THROTTLE or it will squirt fuel in from accelerator pump and flood or cause kick-back.


Exactly as said above. Step 1 thru Step 3 is used to get the piston in the proper location to allow it to be kicked over. It sounds difficult, but is rather easy once done a few thousand times!!!

And you can replace the exhaust cam with one that has an auto-decompressor built into it, and then you won't have to go thru this "routine" to kick the bike to life. Instead, just kick like a two stroke.

  • Pooley

Posted March 08, 2013 - 08:19 AM

#7

If you've accidentally flooded the engine with too many twists of the throttle, flame-out, or crash, you typically restart the bike by pulling the red knob open, which is the "hotstart". This leans out the carb quite a bit for easier starting in these situations. If you've really flooded the carb, and the hot-start doesn't quite do it, you may need to clear things out by holding the compression release open, and then kicking over the engine a dozen or so times. Then start as normal.

After you've cleared the engine, or from a cold start, use 1-2 twists of the throttle maximum before trying to restart the engine, but like mentioned before GIVE NO GAS while kicking. A lot of people remove their hand completely from the throttle and place it on the front brake reservoir to make sure they give no gas while kicking. This is especially important if you've come from 2 strokes.

  • ian505050

Posted March 08, 2013 - 02:38 PM

#8

Thanks for all the replies, the owner before me started it up in front of me, but it was warm when he started it so i assume he may have had it running before i turned up to make sure it started straight away.

So i have not seen it started from cold yet, i guess it could take a while with my poor teqnique.

  • allterra

Posted March 08, 2013 - 03:03 PM

#9

It's choke
Automatic Coast Valve with Hot Start system added to it
Idle knob.

Follow the cable on the bar lever, and see where it goes.
It probably goes to the cylinder, which means compression release.

You can get all this info on Google search.

http://www.frankmxpa.../-Yamaha-WR400F

http://www.motorspor...400ds/index.htm


What is an automatic coast valve?

  • ian505050

Posted March 08, 2013 - 03:50 PM

#10

What is an automatic coast valve?


stops the sea coming in land i believe.

Edited by ian505050, March 08, 2013 - 03:50 PM.


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  • mac the knife

Posted March 08, 2013 - 04:11 PM

#11

hi ian505050,
like you i am new to this site and i am a new and very proud owner of wr400f. i bought mine as a bit of a basket case and set myself the challenge of =-
1, stripping it partially down to weld the head
2, getting it running
3, getting it to start 1st,2nd or 3rd kick
4, getting it mot,d
my past bikes have all be either superbikes or super sports so my fist findings are that these things have not stayed shiny side up very often. everywhere i looked there was signs of damage.
as i bought it
mmWAr8JdDIBoltt4RC9I1fg.jpg
this is what i had to do to the head
IMG_0078.JPG IMG_0083.JPG
fortunately i am an engineer so i can do this sort of thing at work, otherwise i would have stayed away from this one on fleebay.
now i am stuck at stage 3 !! once it is stared it will go like stink round the track my bud has built in one of his unused fields, but it is still a bitch to start. next week a friend is going to put the carb in his ultrasonic bath at work. hopefully this will give me a good grounding to weed out any starting problems,
i have also in the past done mods to my bike the easy way, (taken it to a bike shop! ) but with this bike i am attempting to do it myself, so this week I'm going to try and change the fork seals, wish me luck !!

based in worcestershire and looking for some good green lanes if you know of any

  • mac the knife

Posted March 08, 2013 - 04:31 PM

#12

P.S the red knob is the hot start knob, it does the opposite of a choke. where a choke adds a little more fuel to the the air/fuel mix, the hot start adds a little more air ie=-
choke = rich mix
hot start = lead mix
the black knob bellow is for setting you RPM at idlle

  • The Anvil

Posted March 08, 2013 - 06:11 PM

#13

Good advise on the starting procedure. When I first got my bike I had trouble starting the thing, especialy after dumping it on a hill. After alittle time it becomes second nature and almost always starts on the first kick. On cold starts I let it idle with the choke on for a couple minutes and it rarely gives me any trouble. It's fun watching buddies try to start it. He he

  • ian505050

Posted March 09, 2013 - 02:07 AM

#14

Hi Mac the knife

I also ride sports bike and decided to start off roading due to the poor weather.

The WR400F was bought blind and i had no idea what i bought until i got home.

ps. fork seals are not that hard but dont buy cheap ones, make sure the fork is not bent which is causing it to leak and remove any pitting of the fork legs or you will have it all to do again.

Join the Trail Riders Fellowship who will have meetings in your area and go out in small groups green laning.

  • mac the knife

Posted March 09, 2013 - 04:07 AM

#15

ian505050,
it is such a culture shock, every time i take something off to check, there is some thing that needs repairing!! the last owner let the MOT Lapps for the last 3 years so i think he was more about riding it and less about keeping it in good order !!
that said i am enjoying the challenge. most of the things wrong with it i have been able to either repair or make new at work.
i suppose my only gripe is that people seam to insist on using crap galvanised phillips head bolts and screws. i must have used about a gallon of WD40 !!
thanks for tip about checking the fork are straight. when i remove them i will check them on the measuring table at work.

  • Pooley

Posted March 09, 2013 - 12:38 PM

#16

My advice for regarding the ACV is to disable it completely. There are stickied posts on how to do this (or there were at some point in time). I found that once it was disabled, it was a lot easier to tune the low end.

Also, don't believe the people who say that the 400, or 426 are impossible to start and would tell you to just get rid of the bike for something easier to start. Once properly tuned, the bikes start just as easy as any other bike. I haven't been able to ride my 426 since last November (due to the winter), and it has been sitting in a garage. I would bet $25 that I could get the bike to start on the 1st or 2nd kick, and $100 by the 3rd. I do not have the auto-decomp cams, nor do I have any magic parts to somehow make the bike start easier. What I do have is a properly jetted carb and a well maintained bike.

Learn the starting drill so that you could do it in your sleep, and you will never have problems.

  • ian505050

Posted March 09, 2013 - 01:56 PM

#17

I haven't been able to ride my 426 since last November (due to the winter), and it has been sitting in a garage.


Really?

I have done 3000 miles on the wr250 from November to February over winter, most of it in conditions like this.

I changed the oil every 600 - 700 miles and adjusted the chain and the bikes been fine. Oh and swapped the rear tyre.

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  • ian505050

Posted March 09, 2013 - 02:00 PM

#18

ian505050,
it is such a culture shock, every time i take something off to check, there is some thing that needs repairing!! the last owner let the MOT Lapps for the last 3 years so i think he was more about riding it and less about keeping it in good order !!
that said i am enjoying the challenge. most of the things wrong with it i have been able to either repair or make new at work.
i suppose my only gripe is that people seam to insist on using crap galvanised phillips head bolts and screws. i must have used about a gallon of WD40 !!
thanks for tip about checking the fork are straight. when i remove them i will check them on the measuring table at work.


Road bikes can do many miles with no maintenance, off road bikes need something adjusting or re-greasing every few hundred miles

Yer, i swapped all my fixings for high grade stainless steel when i got the bike.

I use this guy for fixings, the stainless steel is really good quality and does not rust.

http://www.ebay.co.u...984.m1439.l2649

  • ian505050

Posted March 13, 2013 - 12:33 PM

#19

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Bikes now back together :ride:

  • mac the knife

Posted March 15, 2013 - 11:52 AM

#20

ian505050,
your bike looks like it's in a lot better shape than mine (mine is the one in front of shot ) i am waiting for my carb to get back to me from ultrasonic cleaning, so i thought i would ask a few questions in the hope that someone will know the answers :-)
once i refitted the head after welding i reconnected the decomp mechanism, but i am not sure if i have it adjusted correctly, sometimes when i start the bike the leaver goes very soft like there is no tension on the cable.
and the other thing is after i have pushed the kick start just past TDC ( with the comp leaver in) i let the kick start return to the top, and try to kick it it. every so often the kickstart goes half way and then it feel like i have hit a brick wall. it does not feel like a kickback where the kickstart pushed back.
any suggestions would be very helpful. my best mate has a wr400f 1999 just like mine and his does not have any of these symptoms.
could they both be related ?

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