WR400 - How to jet - Guide?

Well recently I've installed a Yoshi RS3 full system on my 2000 WR400F and its been fouling plugs something shocking. I might get 4 or 5 1 hour rides out of it before I need to strip the bike and either clean or replace the plug. Since putting the new pipe on I've been planning on having it rejetted by a professional since I wouldn't know where to start myself; but being the quick learner I am I thought I'd ask all of you for a bit of a hand! I'd rather learn all this myself anyway, any knowledge is good knowledge in my opinion :banana:

Well after a little research here on TT I've concluded that I'm running to 'rich'. I'm relatively new to this bike; well to be honest I'm pretty new to enduro bikes all together. What I'm after is a bit of a 'physical' guide, preferably with a picture or two on how to, and what to jet. I've played around with old farm bikes a bit but I'd rather not mess around or experiment with this toy unless I know what I'm doing. Anyway this 'guide' could include whether I need to remove the carby from the bike, and if so what needs to be removed exactly. Is there any easy way or short cuts to do it? Where abouts the jets are that I need to adjust and how I'm supposed to adjust them? As I said earlier I'm quite a quick learner and don't think I'll have any problems with a little bit of direction from my fellow TT members :lol:

On another note lately my rear suspension has started squeaking rather badly as if it needs to be oiled or greased. If that's the case is there any particular part that needs to be greased/oiled? And if so what grease/oil should I use? If the problems a little more serious and I'm going to have to remove the rear shocker, whether that be to replace it or clean/oil it, what exactly needs to be removed to get it out?

I know I'm asking a lot but I havn't managed to find the information anywhere else, and I'd really like to understand my bike a bit better so I can do all of this myself in the future :excuseme:

If anyone can help me out I'd extremely grateful :excuseme:

Edit: As far as I know my bike is pretty much stock. The only mods I'm aware of is the Yoshimura RS3 full system that I recently installed, and according to the previous owner YZ Jets have also been installed

Thanks a lot fellas :lol:

Well I managed to get out the carb with few hassles, and I thought I'd begin with the basic jet needle clip position. At the moment I'd just like to stop the plug from fouling up every few rides so going by the service manual I shifted the jet needle clip up a notch to make it leaner. Hopefully this does the trick for now. I think I'll play around with the other jets soon enough anyway, but for the moment I'll stick with this. The bike seems to be running smoother but I guess a few more rides will let me know for sure :excuseme:

While you were in there did you write down what jets you are currently running?

No, I didn't this time. Going by the trouble shooting section of the manual I only ended up adjusting the jet needle clip position. I didn't bother opening up the base of the carby to check the other jets this time. I plan on opening it back up in a week or two, but until then I'll see how the bike runs. I'm going to go and get a brand new spark plug to test it with for the moment. I'll fill you in when I open it back up anyway

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