Bike Dying! Need Help!!

I have a 05 WR450. The bike has a FMF Power Bomb with Q2, and power now. The jetting is a JD jet kit with Boyseen Power Shot Accelerator Cover.

I also use a Zip Ty Fuel Screw and Rekluse Auto Clutch.

Here is the problem:

If I'm on a serious up hill and have to slow down quickly for a turn, and then I chop the throttle from about 0 to 1/8th of a turn, the bike sometimes dies. This really became apparent when I put on the Power Shot which leads me to just removing it and putting on my old pump cover, but I was wondering if anyone else has had this problem.

I can also make the bike die when idling by chopping the throttle quickly a couple of times in the garage in neutral.

I contacted JD Jetting and they told me the WR450 doesn't need the Boysen pump cover, but I did notice the bike cleaned up very nicely after I put it on except for this 0 to 1/8th throttle problem.

Any suggestions would be greatly appreciated.

Man I am not an expert but I ride the same bike..Mine did that for the longest time so I reJetted using JD's needles and all. Once I dialed that in your problem sort of diminished for me but I can kill mine too sometimes if I just try and go nothing to Gas real quik-like. Anyway you need a fix for your trouble right...heres what I did to pretty much keep that from happening...Turn the idle up !!!! It works for me daily...hope that helped :thumbsup:

Sounds like you need to tune your leak jet circuit for the AP. I believe this would be a fat bog, accentuated by the uphill condition. Just my 2c, anyone else??


How the heck do you do that?

Yep, it sounds like a rich bog. One of the quirks of the Rekluse is it's tendency to stall when the bike is jetted too fat. With your Quickshot, you've essentially richened up your AP circuit. You need to tune the AP for the proper squirt duration. Read this and grab your manual...SC

Clark to the rescue!!! You are in good hands now.

I just re-read your post and have a question...when you say "chop the throttle", are you meaning to say you're opening or closing it? Chopping is generally understood as quickly coming off the throttle, however, it sounds like you have the off-idle bog wherein the bike will die if you wick it open from idle. Turing up the idle is NOT a fix for it. That's like using a bandaid for an amputation. Also, checking throttle response from neutral is no indication of proper jetting. The bike must be properly warmed up and under load. If your problem is occuring when you give it gas rather than not, then it's the AP circuit and refer to my previous post. If not, then it is somewhere else and I'll need some more info. Lemme know...SC

What I mean by choping the throttle is that your on the Gas and you get off the gas very quickly, then back on it in quickly. But the bike it quitting when I get off very quickly, and then just "blip" the throttle to like an 1/8 of a turn.

For instance. I was riding up a steep up hill at a decent pace, when I got to the top onto a fire road, the sloap of the hill got steeper, but I wanted to turn right to get on the fire road. So, I choped off on the throttle, then just bliped it to carry me over the steep part, but slow me down so I wouldn't blow through the fire road and possibly get struck by another motorcycle or vehicle..

This also happens when I'm trying to go slow up a hill and the just chop on and off the gas to get a little momentum before I really get on the gas when the wheels hooks up. Sometimes the bike dies here as well.

What are your jet sizes, i.e. main, pilot, leak, starter? Also, which JD needle are you running, # of turns on the screw, and at what elev. and temp?...SC

lean out the pilot one step,and adjust your fuel screw accordingly. if your running a 48 DEFINATELY go to a 45. and if you already run a 45, try a 42(i ran 42/165 in the summer mths with my 04 WR). the rekluse requires you to stay borderline lean off the bottom. the quickshot definately helps as long as your AP timing is correct :thumbsup:

I'm using the stock pilot(Don't know what that is, but I'll look), Stock leak(Don't know, but I'll look), JD Blue Needle in the 3rd position, and the JD 168 Main. My fuel screw is out 1.75 Turns. I turned that sucker in and out to no avail. Temp lately has been aroun 65-80 degrees.

I have the clip in the 3rd position because I ride mostly in the 0-3000 ft elevation.

Looks like I have to lean out the Pilot based on other comments.

This is what I came up with for mine, based off Indy's original chart. I have almost the same setup as you except for a Ti PowerCore instead of the Q2. The most important thing to do first is get the AP set correctly. The little key Boyesen sends with the Quickshot is useless, follow the manual. Stock jetting for the '05 is a 45 Pilot, 50 Leak, 165 Main. Unless it's extremely hot and humid, I think the 42 Pilot will be way too lean...SC

Elevation 0 to 4,000 feet:

30 to 45 degrees: 172 main, JD Blue #5, 48 Pilot, 2.0 turns, 75 starter jet, #0 leak jet

45 to 60 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #35 or 0 leak jet

60 to 75 degrees: 170 main, JD Blue #3 or JD Red #5, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet

75 to 90 degrees: 168 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #50 leak jet

90 degrees plus: 165 main, JD Red #4, 45 Pilot, 2.0 turns, 65 starter jet, #60 leak jet

the 42 will work well with the 168 main,may have to go back to clip 4 and run the fuel screw out to 2 or 2 1/2 turns. hey it won't hurt to try its only like $7 for the jet. it took me almost a yr to figure out correct jetting with the rekluse,and to make it work correctly it needs to be lean. a big misconception with the wr is that the ACV introduces air on decel for emissions control and people think the popping on decel is a lean condition. i'd disco the ACV and you'll finally be able to jet it correctly. but thats just me :ride: sorry about that originally i put AIS and have corrected it to ACV :thumbsup:

I went to my manual and couldn't find anything on how to set the AP timing. But as far as I know it's standard. I haven't messed with it ever.

I then went to your attached links and couldn't understand what the heck you and JD were discussing. I understand 2 stroke jetting, but this AP timing and such for 4 strokes is killing me!

I did see your jetting recommendations, THANK YOU. I'll pick up some of the jets you mentioned and give it the old college try.

My question back to you is that you mentioned a 48 pilot versus the stock 45, meaning to richen the pilot jet, yet lean the leak jet? I just want to make sure. You also mention to change the Starter jet to 72 or 70, can you tell me the stock starter jet size?

THANK YOU SO MUCH FOR YOUR HELP. I'll be getting the jets this week and will keep you posted.

The AP timing procedure is in the carb section of the manual, section 4-18. You need to put a 3.1mm rod (approx. 1/8") under the carb slide (throttle valve) and then adjust the AP screw until there is no play in the cam/link. Then, using a video camera, film and time the actual fuel squirt as it comes out of the nozzle in the carb throat. Using different combinations of leak jets and AP diaphragms, you can alter both squirt volume and duration. From my experience, the proper squirt duration is around .8 seconds with a steady, high volume squirt.

I'm not going to lie to you and tell you this is a quick and easy job, 'cuz it isn't. It's tedious and time consuming, though not technically difficult. Perhaps it was a bit of overkill, but I had a serious bog until I went this route. Now, no bog. I hope that makes it a bit clearer for you...SC


Have you tried the red marked needle?

Please give red in #5 from top a try. With the bike fully hot and having been ridden for about 20 minutes, try turning the fuel screw inwards until the motor slows by ~300rpm. From that point, turn the fuel screw outwards 3/4 to 1 turn.

Did you get the kit recently? We are including a pair of O-rings in the YZ/WR kit now to use on the accelerator pump linkage (2 levels of pump adjustment). This adds some snap to the accelerator pump. If you need the O-rings, please send me an email and we will mial them to you at no charge, regardless of when you got the kit.

We recommend the factory setting for the accelerator pump. My quick and easy setting is to turn the pump timing screw inwards until you can push down on the linkage and feel some freeplay. Turn the screw out 1/4 turn at a time until the freeplay is gone. Then, turn the screw 1/4-1/2 turn inwards to add back a tiny amount of freeply.

This is usually near .1 inches or 2.5 - 2.7mm gap between the black plastic linkage and the metal plate that the screw threads thru.

Ride the bike and evaluate with the red #5 setting and let us know your progress.



Thank you James for your input. I purchased your JD Kit the week I bought the Motorcycle and have had it about a year and a half now.

I'll try removing the Blue Needle and replace it with the Red Needle in the 5th position like you mentioned.

Should I also change the pilot jet and leak jets like you suggested in other posts that I've read?

PS - My AIS kit is in fact removed and plugged. I did all the free mods that are posted for the WR450's as well as the other things I mentioned in my previous posts.

Do one thing at a time or you'll never know what the results are. If something works, stick with it and move on to the next tweak...SC

Thank you all for the help.

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