Starting from scratch

[clark4131]

I just can't seem to get over this bog situation. The bike runs about 90% perfect, but I so want that extra 10%. There are those that have found it and I hear they live in Xanadu. Well I want a house there too. I'm going to bring the bike back to stock, except for the free mods and the FMF system, which pretty much means just the carb. My #50 leak jet is on order since I soldered the OEM jet shut. I've also ordered the full gamut of leak jets and an '04 WR needle. I think I've just put the whole carb so out of whack due to all my tweaking, that I just need to go step by step so I can really find out what works. Now I just need to convince my wife to let me have a day or two alone with the bike so I can accomplish my daunting quest. It will be a long journey, but hopefully a fruitful one...SC

P.S.- My JD Kit instructions went bye-bye, so if anyone has a copy and can email it to me, I'd be most indebted. TTFN...SC

[Indy_WR450]

I just cant understand why some bikes have the dreaded bog and others dont. NC Mountainman and I have been discussing this at great length over the last few weeks while he was dealing with his new YZ450 mini bog. I have come to the conclusion that the the FCR pumper carb has advanced to the point that it is so complicated with so many overlapping circuits that you cant duplicate the performance from one batch of carbs to another. The new FCR is so much better than the WR426 and WR400 versions it is silly to hear about complaints with the new 450's. I think fuel injection will be our ultimate solution to the issue. Meanwhile some of us will live inside the gates of Xanadu and others will be looking in with very litle hope of seeing the gates open. ?

[clark4131]

...some of us will live inside the gates of Xanadu and others will be looking in with very litle hope of seeing the gates open.

Sure, rub it in why don't ya ? . I will be reporting back as I go through this thing, so rest assured I'll be tapping you for help ? ...SC

[Matty05]

I think fuel injection will be our ultimate solution to the issue.

Right on! I nearly brought a GasGas or a Sherco for this reason. I haven't found any where to get aftermarket Magneti Marelli injection systems though.

I don't think it will be long now untill injection hits the big time as new bikes on the scene use injection as it is heaps easier for ADR requirements. Just emagine never having to much around with your jetting!!! ?

[flatnacker]

Just emagine never having to much around with your jetting!!! ?

Yeah instead we will be mucking around with mappinng for our power commanders ? It never ends...........

[extex]

Steve, I'm definitely an amateur compared to a lot of the guys here but I did have several years of MX racing 2 strokes when I was a teenager. I bought an 05 wr450 in March and immediately started with the mods. I have the JD kit using 170 main and (I think) blue needle at position 3. ZipTy at 1.75. Snorkel removed and PMB insert in stock exhaust. I think it is a little rich, starts immediately, choke on only about 15 seconds, but I really don't have a bog that I can detect and I've never fouled a plug. It could be that it could be much better and I just don't know it but if I'm in the right gear it is going strong with a twist and there is no way I could kill it in neutral by revving it quick. I have had a #40 leak jet in my tool box for a month but am hesitant to put it in because I don't know how much it will help. I am going to open up the airbox some more to lean it out a little and maybe move or change the needle to red since it is hot this summer in Michigan. I'll probably try the leak jet at that time.

Also, I have the JD instructions and can email them tonight if you still need them. PM me with your email address if you do.

[Texas4play]

Good luck Steve! I can email the JD to you if you need it. BTW, once you get to Xanadu, Jamie Little and Molly Culver prep all our bikes for us ... you just can't see them thru the gates, they are back by the Oasis pool ...

[Dan_Lorenze]

I just cant understand why some bikes have the dreaded bog and others dont. NC Mountainman and I have been discussing this at great length over the last few weeks while he was dealing with his new YZ450 mini bog. I have come to the conclusion that the the FCR pumper carb has advanced to the point that it is so complicated with so many overlapping circuits that you cant duplicate the performance from one batch of carbs to another.

This is the conclusion that my father and I have come to. We've ordered several bikes in pairs, 2-400's 2-426's and 2-450's.. They have been different, he's had JD kits and I've always been on OTC jets. Regardless, I agree that these bikes come from the factory different. What has worked on my bike makes his bike bog, crazy.. ? Good point Indy.. ?

[Texas4play]

I'd agree with that too Dan, another TT'r in my local area bought an '05, asked me what specs I had and it didn't work for him at all.

[clark4131]

Here's what I've learned so far...I went to a 48pj/168mj/40lj/JD Red #5, but I removed the PowerNow, the Quickshot and Barnum's Pro Airbox kit. The bike did extremely well in almost all the categories. At about 5500' or so, the throttle response was spot on and the bog disappeared completely , though it was evident in my garage at around 4940' (I'm going to GPS the location next time to get an exact altitude). I'm going to try the Blue needle in several locations next as it's obvious I have a lean condition in its effective range with the Red. I'm pretty confident that I can cure the bog with the proper jetting and needle configuration. After I get that done, I'm going to add the various widgets and gizmos, i.e. the Quickshot, PowerNow and Barnum's Pro, to see what I get from those, if anything.

I hope y'all don't mind that I'm going to use this thread to update my findings. At the very least, I hope it'll serve as a log of things someone can expect from various add ons and tweaks on these bikes. Thanks for indulging me ? ...SC

[extex]

I, for one, appreciate hearing about your findings. I did a lot of mods at the same time so I'm not sure of the effects individually. Keep us posted.

[shorty87]

Steve, try going back to the 50 leak jet. I did all the mods and changed to a 40 leak jet all at the same time. No matter what I did to this bike, it had a terrible bog. Put the carburetor in a vice and turn the throttle. You might be surprised on how much fuel is being pumped through the squirt. It looks like enough fuel for a 350 Chevy! I put the 50 back in and it made all the difference in the world. I can jet my bike now to where any changes I make are noticeable.

[clark4131]

Success!!! Went for a ride to day and I believe I have the thing dialed in as good as anyone could get it. Here are my conditions and settings...

2005 WR450FT

80 Degrees

9% Humidity

4500' - 5500' ASL

Eastern Sierra Singletrack - Sand and Rocks

All Free Mods

Airbox Punch Outs Removed

Twin Air Filter

FMF Q2 w/ SX Powerbomb

Boyesen Quickshot

Powernow

NGK Iridium Plug

168 Main Jet

45 Pilot Jet

50 Leak Jet

70 Starter Jet

JD Red #5

2 Turns out - Zip Ty Fuel Screw

Idle set at 1900 +/- 100

I experienced no low end bog, no flattening in the mid-range or top end. I couldn't have asked for a better performance from the bike. Last ride, I had the needle at #4 and I had bogging and overheating issues. In #5, they disappeared completely. Of course, all I had to do was look at Indy's Jetting Chart and I would have been in the money all along, but I was always tweaking the absolute wrong circuit which threw everything else off. There are couple little nuances I changed such as one up on the Main and two on the Starter, but otherwise the chart is the way to go. So boys and girls, there you have it. I'm not screwing with this thing anymore until it gets colder and then it's just a change in the pilot for me. That's it for me and my jetting woes. Thank you and good night...SC

[Indy_WR450]

It is a great feeling when the bike is jetted right! Congratulations on not giving up!