[esaresky75]

2007 CRF450X
NE PA 50-80 degree weather and 500-2500 feet.

After taking a 2-year hiatus on making my bike run proper, I need a refresher course on what each jet is and where. I remember a diagram showing each item and it's name but can't find it now. Anyone have a link?

I have a new in box but purchased two years ago R&D Power Bowl part # 59-1003, R&D Flex Jet remote fuel screw kit (already on the bike) and the JD Jet Kit part # JDH006 (also already on the bike).

I purchased bike new and engine/pipe is stock. I cut the airbox to match the 450R, deleted the smog pump, removed muffler baffle, etc, etc. I re-shimmed the valves once in 2009 or 2010.

I'm not looking for power increase, just have quick, crisp throttle response not stumble and backfiring.

What recommendations for achieving my goal besides the above mentioned items? Since the bike is 7 years old and was not ridding much in the last two years, I will replace the floating valve seal, what else?

[Harkon]

2013 450X here. Just cut the top off of the air box, not the full conversion but close. Added the JD jet kie and R&D fuel screw. Pilot jet remained untouched. Main jet to 162. Needle in 4th position. Baffle is still in place, everything else is pretty much stock except for desmogged.

Response is virtually immediate. Very nice indeed compared to how it came. I cannot imagine it being much more responsive.

Really good pics here
http://crfsonly.com/howto/450x/jetting/ ... needle.php

[Leardriver]

Your bike is real easy to jet, and not particularly finicky.
165 main, 45 pilot, fuel screw at 2.0 turns out.
The leak jet is the fad of the month. You don't really ever have to touch it.
I block them off completely on the X, but then I will ride a stock one and it feels great also.

[esaresky75]

Your bike is real easy to jet, and not particularly finicky.
165 main, 45 pilot, fuel screw at 2.0 turns out.
The leak jet is the fad of the month. You don't really ever have to touch it.
I block them off completely on the X, but then I will ride a stock one and it feels great also.

I already have a 165 and 45, installed in 2009. Bike runs better but not like it should. IMO, it's a POS but I have to make do for now.

[Harkon]

I think it's like 75 said. With what you have it should work pretty well. Maybe look past that a bit for the moment. Filter clean? What's the plug look like? Valve clearance? Could be you have something else going on other tan fuelling.

With mine how I have it now, just broken in, it is crisp, responsive and no backfire pops or bogs, under load or otherwise. I know up to 08 the JD kit recommended a change (mod) to the accel pump. Did you try that?

Sorry I don't have a better answer, just pitchin' ideas.

[hall_philip]

I would give that carb a good cleaning. I use chem-dip to clean my carbs first and then hose them down in carb cleaner. make sure you get all the ports washed out good. replace the AP diaphragm and the floating valve seal. make sure you get it on there right. its easy to botch it. make sure the slide and floating plate are not worn excessively. float level I believe is spec at 9mm, don't quote me though. your on your own as far as jetting, but the info you have already received should put you in the ball park, I would replace with new one's if it were my bike. there cheap.

[esaresky75]

AP mod as in tying with wire or o-ring? I thought 2006 was the last year before it was corrected by Honda? I do believe my diaphragm has the higher rivet and I'm going to replace with the new style.

Just to clarify, I'm not saying the CRF450 is a POS, I'm saying MY 450X is a POS. I purchased it new and I feel out of the box it ran worst than others and the few carb mods I did improved it but not corrected it even close to acceptable standards. The last few years I have ridden it and just put up with it but now want it to run like a Honda should.
Below are the parts I'm purchasing, anything else? I already have the R&D Powerbowl 2 and the JD jet kit.

[Harkon]

Yeah, that's the AP mod I was talking about. I do t know for sure when it was fixed so you might be right. I'm sure the jet kit said it was pre '08, but you may be right.

I know what you mean about being a bit pissed about how it runs. Mine was almost unrideable out of the box, and the dealer left me pretty much high and dry. The members here were a great help and we finally got it figured. For me a JD jet kit installed per instructions and a R&D pilot screw at 1 1/2 turns hit a sweet spot for me. Wish I could help but I'm new to this bike. I've been away from dirt bikes for a lot of years, and before this everything was 2 smoke. These new thumpers are waaayyyy different to anything I've ever worked on before.

[Leardriver]

In 2007 the accelerator pump was changed, and doesn't need the same kind of mod. I think the rivet on the diaphragm was changed to increase squirt duration.
These are such tiny little fine-tuning steps, and they won't make a bike run bad if not done.

[esaresky75]

Since I'm installing the R&D Power Bowl part # 59-1003, it comes with a A/P spring. I also purchased from here the Honda updated accelerator pump kit (to get the new style diaphragm) which also has a A/P spring. My spring & the one from the update kit feel about the same. The one from the R&D kit is stiffer. Which should I use? Should I also use the new rod?

[esaresky75]

Nevermind which rod to use, they're the same length. So out of the updated A/P kit, I will be using only the diaphragm, that was a waste of money. I could have it by itself.