Anyone know how to get to the main jet on the 450 ?
I got a WB pipe and the instructions say take 4 bolts off the carb cap (IM assuming they mean the TOP ) - and then the 2 smllaer bolts on the slide - and replace it with ... blah - blah ....

i did the 4 cap and the 2 slider bolts - but now the mechanism is in the way - and i cant pull off the piece to get to the bottom ?

Does this sound right ? when i had my 400ex - it was dowe from the bottom - i just thought this one was different - someones' got to have some idea or picture on how to do this ??? Im having second thoughts now....

oh brother... IF anyone can help.. Id appreciate it !


Thanks.
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The main jet on the 450r is in the same spot as the 400ex. On the bottum of the carb is a big hex nut, remove this and get a 6mm socket on a 1/4 drive ratchet. Reach up inside the hole and you should be able to feel the main jet.....If you loosen the carb from the intake boot where you can rotate the bottum of the carb towards you, this helps alot.....From what you were describing in your post, this is where you adjust the needle clip position.

 

CrazyATVDad,

The part that you are referring to as a cap is called a float bowl. The float bowl is located on the bottom of the carburetor. By removing the float bowl will give you access to all of the jets for the carburetor. There are 4 Philips head screws that fasten the bowl to the carburetor, remove these 4 screws and remove the bowl away from the carburetor to change the jets needed for any after-market mods (ex. high flow exhaust system, air filter, piston, etc). You can also access the main jet by referring to what BAD450Z stated in this same post.

BAD450Z stated:
The main jet on the 450r is in the same spot as the 400ex. On the bottom of the carb is a big hex nut, remove this and get a 6mm socket on a 1/4 drive ratchet. Reach up inside the hole and you should be able to feel the main jet.....If you loosen the carb from the intake boot where you can rotate the bottom of the carb towards you, this helps a lot.....

I recommend for you to take the extra time and educate yourself my removing the float bowl so you can see how the carburetor works and all the parts and pieces that are involved. The Main Jet is located in the center of the carburetor, the stock main jet size is 118, which is stamped on the side of the jet. The number refers to the size of the hole which allows air and gas to flow through the jet and into the carburetor etc. Once you feel comfortable and need to change the jet on the fly by dialing it in to your exhaust system, then loosen the intake boot and the boot from the air box and rotate the carb to get access the 17 mm? hex nut located on the bottom of the float bowl. Remove the hex nut and replace the jet by using a 6 mm socket with an extension, do not over torque the jet!

Good luck, and if you have any question feel free to ask. Let us know if this information helped.

Tim

 

Hey Bad and TIMS - thanks for that info - Its been yrs since i had done this - now i remember -and you're right -
I was hoping there would be pictures somewhere on this topic - couldnt find any.
might finish up the job tomorrow I hope.

WBrothers suggested 180 on main using their new E2 exhaust - thats a big jump ...if they are 118 stock ???
its tested and is suppose to work just right - so we'll see I guess.

but thanks for the info - maybe Ill take my camera and take some pics of this procedures for someone else... would be helpfull....


later !

 

cool.
thanks
where and how do you move the needle on this ??

 

Guys thanks for that info .

I did finally finish this job - but i have one last question - i did not move the needle - although WBros said move it up (RICHER) -- NEW Jet is in place and it runs perfect except for one small thing.

if i floor it in 1st and 2nd gear - it cuts out right before I shift from 1-2 or from 2-3 - just a little - of course ive never noticed this stock - but then again I never had to floor it that much -- so Im wondering something.

will moving the needle fix this --- ??? or DO i need to go down a little on the JET size

I took your advice and tore it up over the wknd- and found all kinds of stuff on the carb - and how it works.
i noticed that it seems to be easier to remove the needle from the top ??? i can see the clip on the top - although i didnt try it.

i ended up changing the jet and that was it - but now im wondering if i need to move the needle to fix it.


question is this - is it cutting off because its revving up quicker - and maybe im hitting the red-line ? or just sputtering because of too much gas in those gears. i dont notice it past 3rd gear - but then again im flying after third - so cant tell...

if its just sitting there - and i floor it for a few seconds - it putters a little on the WAY top end...

maybe out on the track ill never notice this - since its too high up there - but it seems like it should be smooth all the way up ???


how can i tell - smaller jet or larger jet --- move the needle or dont move the needle --- does the needle have anything to do with 3/4 to full throttle ???


thanks for ALL YOUR HELP GUYS !

 

Crazyatvdad,

I suggest to move the needle one position on the rich side (move clip down 1 position).

If the engine is having troubles at low rpm (idle to 1/4 throttle), the pilot system or slide valve is the likely problem. If the engine has problems between 1/4 and 3/4 throttle, the jet needle and needle jet (most likely the jet needle) is likely the problem. If the engine is running poorly at 3/4 to full throttle, the main jet is the likely problem.

Hope this helps.

Tim

 

I just wanted to say, Nice post Timscherer. That was extremly informative.
FYI @ 500 Feet, I am running a 182 with no lid, K&N, LRD pipe,HRC cam, and a HRC needle on middle clip. Stock settings on everything else.It runs great.My friend went to the ITP race in Glen Helen (sea level basically) , he jetted to a 190, with the same mods as I have.
Its a huge jump, but I think that the factory set them up very lean to get a green sticker.
Duncan Racing, as well as a few other shops, have said they like the stock needle better than the HRC. I have not tried it yet.

 

Cool info KGB...

I have WB pipe w/180 right now - Im wondering if I have to go to 182 also ?
my prob seems to be 3/4 to full throttle --

Agree Timsherrer... good info to have - i havent touched the needle yet - but I prob will just so it runs richer - i will try that tonight.

appreciate the info on this topic - good to know -


BTW, did you guys notice a big difference w/pipe and re-jetting - hard to tell for me I havent taken it off-road yet - i plan to go riding this wknd - but on the pavement it sure feels much more 'beefy'....

This bike rocks! Who said 4-strokes dont have enough power ?? They prob havent ridden the new generation 450's.....

 

I re read my post, I meant to say 5000 feet not 500. Sorry for any confusion....
I had a pretty big diff, with pipe and jetting.