Cool vid! I lucked out when I bought my 99 wr400f and the previous owner gave me a yz450f carb that he never installed. I got tired of messing around with the old stock carb and threw on the 450 carb and it ran way better. Didn't know about the slide cracking issue. Looks like you also plugged the old hot start hole from the air box too. Nice work!
Hi mate couple of questions if I may, when you removed the hot start set up what did you use to blank off the remaining holes on the head and air box intake? Did you also retain the hot start feature on that kx carb? Also would you happen to know if the 06 carb would be just the same as the 07 you used? I’ve found one local ish to me for £280..
The kx450f carb is the same for 06 to 2008 models. Only difference may be the jet sizes, which I ended up changing anyway. I blocked the hot start hole in the head with one of these screws. Click the link to see oemdirtbikeparts.com/product/dirt-bike-hot-start-plug-block-off-upgrade-titanium-carburetor-plastic-remove-kit/yamaha-1999-wr400f/ In the vid I show I blocked off the port to the cylinder and airbox with some rubber caps and zip ties to hold them in place. I also used the kx450 carb hot start set up I just ended up buying a hot start lever which I mounted on my bars.
I have a WR 400 and I'm going to put all new plastics on it, and I was looking for a carb kit and I just came across your video, im thinking of buyiny a new carb like your one how much was your upgrade carb??
Hello Friend. I have made the same combination. I have wr400f but carburetor I got from wr450f. I drove it with more compression but the grenade warmed up very quickly, it became more red. Is it up to the nozzle you change from 48 to 42?
The pilot jet is based on how many turns out your air fuel mixture screw is wound in or out. Fuel Screw adjustment should be between 1 to 3 turns out with optimal idle. If hour bike idles better with the fuel screw out more than 3 turns you need a larger pilot jet. If your bike does not cut off after the fuel screw is wound in past half a turn you need a smaller pilot jet.
I did the exact same thing but unfortunately my bike ended up backfiring like crazy and died out if I gave it gas not exactly sure what it is I’m thinking the needle clip position or should I try that stock pilot jet instead of the 42 mm
I had my needle clip 3 from the top. The Needle clip position affects 1/4 throttle to 3/4 throttle. I believe the 42 pilot ran best. Make sure your idle adjustment screw is near all the way seated when you adjust the fuel mixture screw 1 1/2 turns out.
Hey, I have my 1998 wr 400 and it is a pain in the arse to start. Some days it's as easy as 4-5 kicks and some days I have to keep kicking till it's flooded and I can't ride it to work that day. It still has the manual compression cam and was wondering how much easier does an auto decompression cam make it to start?
Auto decomp cam, makes the bike as easy to kick over as a two stroke. No effort required to kick it at all. I found it really tricky to start with the standard cam
@@TheGingybeardMan Cheers for the insanely quick reply. Also second question do you know how much work it is to do the swap. Can I rookie with patience and planning do it or am I best to see a mechanic?
I purchased mine from mxstore.com.au but here's a link to one on ebay www.ebay.com.au/itm/NEW-YAMAHA-WR400F-YZ400F-1998-2000-HOTCAM-HOTCAMS-EXHAUST-CAM-AUTO-DECOMPRESSION-/223476926636?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0
I'm thinking about getting a chinese clone wr450 carb from amazon for my 99 wr400f, do I need to change throttle cables or tubes or will the stock work?
Thats a good question. I dnt know what cables will fit those Chinese carbs. I'd buy the carb 1st then see if the stock cables work. The stock cable wouldn't work with the kx450f carb though
Just took off the old carb and the throttle cables were toast, the new carb I ordered needed different cables so I just ordered some along with a new tube. I jetted the new carb to 168mj 45pj fuel screw at 1 and 3/4 hope it works
@@itzyaboooiii I'll be going with a 40 pilot jet. With the 42 the bike is tricky to start when cold unless the hot start is pulled in. This indicates the carb is running a tad rich and needs a smaller pilot jet to get it leaner.
Been a while since I put her back together and still cant get her to start, 42pj 170mj seemed to start and run but the fuel screw was almost in. I put in a 40pj and 155 mj and now she only burbles but no start. Also I may have messed up my idle adjustment and cant figure it out for the life of me, any ideas?
@@itzyaboooiii I found the 450 carb needs hot start when the engine is cold just to get it started. Give the hot start lever a go on initial start up. I have a 40 pilot in it and the fuel screw out 2 turns. Otherwise the bike idles great and pulls hard through all gears. The main jet size does not affect starting
@@TheGingybeardMan what accelerator cable did u you use? My 98 wr400 has this terrible dead spot down low and I'd love to try the 450 carb maybe tune it a bit easier
@@puddinz9855 I had a lot of trouble trying to tune my stock carb. I used a kx450f accelerator cable to suit the carb. The 450 cable works with the stock accelerator tube
TO NOTE, CORRECT FUEL SCREW ADJUSTMENT SHOULD BE BETWEEN 1 TURN TO 3 TURNS OUT FROM ALL THE WAY SEATED NOT 1/2 TURN TO 3 TURNS OUT.
Cool vid! I lucked out when I bought my 99 wr400f and the previous owner gave me a yz450f carb that he never installed. I got tired of messing around with the old stock carb and threw on the 450 carb and it ran way better. Didn't know about the slide cracking issue. Looks like you also plugged the old hot start hole from the air box too. Nice work!
Thanks mate, yes I sure did plug the air box where the hot start ran. I found the stock carb pretty difficult to tune also.
Can you tell me the jetting?
Thanks for this video I bought this carb on Ebay along with a JD jet kit my 2000 wr400f runs like new this is a must do upgrade for these bikes.
Thats great to hear mate 👍
Did you use a wr400f jet kit
@@wearefarmersnot3875 no I got the jet kit for the 450 carb
Nice work brotha
Your videos never let me down .
Cheers brother 🤟
Good job mate, keen to see how it performs under load.
Same mate, should be able to register it very soon. Just need the hot start lever and some mirrors 👍
Pre 450f's I like it mate.
Hi mate couple of questions if I may,
when you removed the hot start set up what did you use to blank off the remaining holes on the head and air box intake? Did you also retain the hot start feature on that kx carb?
Also would you happen to know if the 06 carb would be just the same as the 07 you used? I’ve found one local ish to me for £280..
The kx450f carb is the same for 06 to 2008 models. Only difference may be the jet sizes, which I ended up changing anyway. I blocked the hot start hole in the head with one of these screws. Click the link to see
oemdirtbikeparts.com/product/dirt-bike-hot-start-plug-block-off-upgrade-titanium-carburetor-plastic-remove-kit/yamaha-1999-wr400f/
In the vid I show I blocked off the port to the cylinder and airbox with some rubber caps and zip ties to hold them in place.
I also used the kx450 carb hot start set up I just ended up buying a hot start lever which I mounted on my bars.
Good job 👍, Always good to work on your own bikes save the bucks..☠️
Thanks mate, sure does save alot of coin 👍
I have a WR 400 and I'm going to put all new plastics on it, and I was looking for a carb kit and I just came across your video, im thinking of buyiny a new carb like your one how much was your upgrade carb??
I found this used carb on ebay for $180
Wich Year for the kx450f carburetor you have choosen?
Greetings from germany and sorry for my Bad englisch.
I used a 2006 kx450f carburetor
Luv Trumpy✌
To old 4 that missile but respect! Bout time ya caught a 3 meter'y🍻👍
Hello Friend. I have made the same combination. I have wr400f but carburetor I got from wr450f. I drove it with more compression but the grenade warmed up very quickly, it became more red. Is it up to the nozzle you change from 48 to 42?
The pilot jet is based on how many turns out your air fuel mixture screw is wound in or out. Fuel Screw adjustment should be between 1 to 3 turns out with optimal idle. If hour bike idles better with the fuel screw out more than 3 turns you need a larger pilot jet. If your bike does not cut off after the fuel screw is wound in past half a turn you need a smaller pilot jet.
I did the exact same thing but unfortunately my bike ended up backfiring like crazy and died out if I gave it gas not exactly sure what it is I’m thinking the needle clip position or should I try that stock pilot jet instead of the 42 mm
I had my needle clip 3 from the top. The Needle clip position affects 1/4 throttle to 3/4 throttle. I believe the 42 pilot ran best. Make sure your idle adjustment screw is near all the way seated when you adjust the fuel mixture screw 1 1/2 turns out.
@@TheGingybeardMan ahh thank you I shall try it right away I watched the video and tried to to preset the screw
Hey, I have my 1998 wr 400 and it is a pain in the arse to start. Some days it's as easy as 4-5 kicks and some days I have to keep kicking till it's flooded and I can't ride it to work that day. It still has the manual compression cam and was wondering how much easier does an auto decompression cam make it to start?
Auto decomp cam, makes the bike as easy to kick over as a two stroke. No effort required to kick it at all. I found it really tricky to start with the standard cam
@@TheGingybeardMan Cheers for the insanely quick reply. Also second question do you know how much work it is to do the swap. Can I rookie with patience and planning do it or am I best to see a mechanic?
@@TheNitrokitten mate it is a pretty technical job but there are loads of vids on CZcams on how to swap out a cam.
@@TheGingybeardMan Cheers, I'll look around and see if reckon I can do it.
What’s the size of your main jet?
Mate it was that long ago I can't recall. It was the stock jetting from factory though.
where and how did you get auto decomp..... tell me please i have a wr400f
I purchased mine from mxstore.com.au but here's a link to one on ebay www.ebay.com.au/itm/NEW-YAMAHA-WR400F-YZ400F-1998-2000-HOTCAM-HOTCAMS-EXHAUST-CAM-AUTO-DECOMPRESSION-/223476926636?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0
What size is your main jet?
I can't recall, but I know it's the stock size main jet from factory.
Kx450 carby plug and play is it? What year kx450 carb
I'm thinking about getting a chinese clone wr450 carb from amazon for my 99 wr400f, do I need to change throttle cables or tubes or will the stock work?
Thats a good question. I dnt know what cables will fit those Chinese carbs. I'd buy the carb 1st then see if the stock cables work. The stock cable wouldn't work with the kx450f carb though
Just took off the old carb and the throttle cables were toast, the new carb I ordered needed different cables so I just ordered some along with a new tube. I jetted the new carb to 168mj 45pj fuel screw at 1 and 3/4 hope it works
@@itzyaboooiii I'll be going with a 40 pilot jet. With the 42 the bike is tricky to start when cold unless the hot start is pulled in. This indicates the carb is running a tad rich and needs a smaller pilot jet to get it leaner.
Been a while since I put her back together and still cant get her to start, 42pj 170mj seemed to start and run but the fuel screw was almost in. I put in a 40pj and 155 mj and now she only burbles but no start. Also I may have messed up my idle adjustment and cant figure it out for the life of me, any ideas?
@@itzyaboooiii I found the 450 carb needs hot start when the engine is cold just to get it started. Give the hot start lever a go on initial start up. I have a 40 pilot in it and the fuel screw out 2 turns. Otherwise the bike idles great and pulls hard through all gears. The main jet size does not affect starting
Hi mate what year kxf carb did you use?
2007 kx450f carb mate 👍 but any 2006 to 2008 450 carb will work.
@@TheGingybeardMan Thanks for the quick response mate. Will definitely be doing this to mine.
@@TheGingybeardMan what accelerator cable did u you use? My 98 wr400 has this terrible dead spot down low and I'd love to try the 450 carb maybe tune it a bit easier
@@puddinz9855 I had a lot of trouble trying to tune my stock carb. I used a kx450f accelerator cable to suit the carb. The 450 cable works with the stock accelerator tube
What mainjet Do you use?
I think it was a 168