Working on the bog (03 WR250F)

Started by meckanik, Sep 11 2003 12:21 PM
13 replies to this topic

  • meckanik

Posted 11 September 2003 - 12:21 PM

#1


Just thought I'd post and say thanks to everyone who has documented their work on trying to fix the bog on the earlier bikes. My 03 (less than two weeks old) has had a bad bog if you wick the throttle from an idle since I got it. Apparently the BG/BK mod won't work on my carb since the pad for the screw is not there. James Dean is not finished with the jetting kit for this bike yet, but he said the CRF 450 kit is pretty close (running the red needle and the 180 main from that kit). I haven't ridden it yet, but it still bogs the same on the stand.

So, I just ordered the P-38 accelerator pump. It should be here tomorrow and I'll spend a little time tuning it and let everyone know how it worked on my '03.

later...

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  • ScottsWR

Posted 11 September 2003 - 12:57 PM

#2

See my notes on the bottom of my post.
I think the biggest help was changing jets and the needle position. The bog on MY bike was there because it was too lean.

Good Luck,

Scott

  • SBG

Posted 12 September 2003 - 06:00 AM

#3

But is your bog gone, or just reduced?

  • YZ_Abuser

Posted 12 September 2003 - 06:09 AM

#4

Quote

See my notes on the bottom of my post.
I think the biggest help was changing jets and the needle position. The bog on MY bike was there because it was too lean.

Good Luck,

Scott

Jetting....MJ-188, PJ-42, Needle-5th groove.



A 188 MJ? You've got to be kidding me. If it's that big you need a much richer needle and get the MJ back down to a high 170s. Is this with the stock baffled exhaust? I just can't see this bike running well at all.

:) :applause: :D :D :D :D :D :D :D :D :D :D :D ;) :usa: :usa: :applause: :applause: :applause: :applause: :applause: :applause: :applause: :applause:

  • meckanik

Posted 15 September 2003 - 03:17 PM

#5

Update:

To recap, the first thing I did to my bike to address the bog was rejet with a James Dean CRF450 kit using the needle he reccommended (not sure of the needle specs, but 5th clip), and a 180 main.

No difference in the bog and I didn't have a chance to test ride it yet.

Next I put on the P-38.
Still bogs, but not as easily (if that makes sense). A really fast wick of the throttle will still bog, but a but slower one won't (where it would before).

Next, got the ZipTy since the P-38 directions say to adjust the idle mixture while blipping the throttle, and this seemed like a good way to access the jet.

Still closer, but it will still bog. Took the bike for a quick ride down the block and 1/4 throttle and up feels much better. Bike feels quicker, but the bog is still there.

I need to spend some more time adjusting the idle mixture and I also want to try the stock needle. The P-38 guys say go with the stock jetting first while trying to dial the carb in.

I'll post more after I finish tuning this week. Thanks.

Jeff

  • TheGryme

Posted 15 September 2003 - 03:51 PM

#6

:)
What altitude are you at?
I have a new 03 wr250f and it was terrible up where I live and ride...that's about 5000 feet. I did all the free mods, no baffle, P38 and Zip Tye and jetted the crap outta it and I finally can ride it the way I like. I can be creeping thru some rocks now and let it idle all the way down in 2nd gear and nail it and it'll go! B4 it bogged so bad that a couple of times it stalled and I fell on my butt. I'll post my combination of jets later....at work right now and can't remember them. This board has been tremendous for help with this bike! :D

  • TheGryme

Posted 16 September 2003 - 11:16 AM

#7

:D I'm Back!
On my '03 WR250F I'm running a 180 MJ, A 45 PJ and the stock Needle at pos 4...these mods and a modified air box, grey wire, P38 and zip tye screw works very well for me at 5000 feet high. It's just a little too fat right off the bottom, so I may actuallt try a leaner PJ soon....just for fun! :)
Hope this helped.

  • YZ250F_Rider

Posted 16 September 2003 - 12:33 PM

#8

I would suggest going down to a 178 for the main before leaning the PJ. It may be all you need to do.

  • aztsail

Posted 16 September 2003 - 01:36 PM

#9

Hey, just to add my 0.02c.. look at my signature. I live at 5000ft, ride up to 12000ft. Bike had a terrible bog off the bottom. Leaning out the needle and richening the pilot circuit helped. (Maybe to rich on the PJ. 45 might be ok). Added the P38. Didn't fix the bog. Experimented with the leak jet size. No effect until I completely blocked the leak jet by soldering it closed! :D Wow, what a difference. No bog at all anymore. Some others have tried this fix without success but I think the carb has to be pretty well tuned before this will work. Good luck. :)

  • Bandit9

Posted 24 September 2003 - 03:37 PM

#10

No effect until I completely blocked the leak jet by soldering it closed!

I second that! I just soldered mine closed today and finally I can rip it and doesn't bog. No p-38, really nothing else, but getting the squirt to just miss the slide and going up to 3rd on the clip. Messing around with the Main Jet now. It would wise to listen to these guys on this board and the FAQ. I followed their advice I am getting very close to total bog elimination. Hell, just where it is at now is awesome. Just like SUnruh said, in 1st and 2nd I whack it and the front end just keeps coming up. Really cool.

  • JimL

Posted 24 September 2003 - 06:28 PM

#11

My bike had such a bad lean bog stock it would die if you wacked the throttle.
I don't have any bog now. :) none. :D Not while riding or on a stand. try this: 42 pilot, obelq-4, 172 main, 70 leak jet, 1 3/4 turns out. I ran this with the free mods and a gytr insert.
When I added a power now I went to #3 position on the needle.
I opened up the side of the airbox and went to a 175 main, this bike really needs more air. This really helped.

Now with a fmf Q and a power bomb header I,m at a 178 main. I highly recommend this set up. The difference over the gytr is huge :D

The stock needle on the 03wr250 is much fatter(leaner) than previous years, and yamaha must have compensated for it with a larger main jet. Just my personal observations, I'm no expert. I decided to go back to the 02 specs and work from there and It solved my problems.

I ride 500-3000 feet. I hope this helps.

  • barton

Posted 24 September 2003 - 06:50 PM

#12

Jim,

I've got the same set up you describe. I'll try your jetting tips. I just installed the GYT tip and its much better than stock. I have a few questions if you have time to answer them.

1. How much louder is your FMF than the GYT tip?

2. Did the power now make much difference, and did you have any trouble installing it on your 03 WR?

3. How did you open up the side of the air box?

Thanks,
barton
03 WR 250F - Throttle stop, gray wire, GYT tip, air box snorkel removed, gettin ready to try a 75 leak jet. I'll probably also go down one on the clip as I think I'm lean. One change at a time.

  • JimL

Posted 26 September 2003 - 06:20 PM

#13

Quote

Jim,

I've got the same set up you describe. I'll try your jetting tips. I just installed the GYT tip and its much better than stock. I have a few questions if you have time to answer them.

1. How much louder is your FMF than the GYT tip?

ANSWER: The fmf Q is slightly louder than the gytr but not much. I don't like a loud pipe and I'm happy with the fmf Q.

2. Did the power now make much difference, and did you have any trouble installing it on your 03 WR?

ANSWER: At first I wasn't sure. I put it in for a couple of rides then took it out, then put it back in. It definately helps the bottom end, but its not something you'll feel all the time if your rpms are up. It helps it pull off the bottom better when you're lugging it. I'm more impressed with the fmf powerbomb header. Before on hill climbs if my rpms dropped due to roots , rocks or rider imbalance :) it would take some clutch work to get the rpms back up. Now I find I can just roll the throttle on harder and it will pull itself out and into the power again with much less, if any clutch. The power now took 2 minutes to install. Just push the boot out of the way and slip it in :D


3. How did you open up the side of the air box?

ANSWER: I downloaded the template from thumperfaq but it was too large so I just estimated and cut two holes like the picture only smaller. the right side has a double panel just drill out the rivets to pull the first cover. I think if I was to do it again I would just drill a series of holes and maybe use some univents. Although I've never gotten any water in my airbox while riding (only washing), and I encounter a dozen mud holes on every ride.




  • barton

Posted 27 September 2003 - 05:09 PM

#14

Thanks for the answers man. I don't really want a loud pipe either. I went so far as to check the GYT against the stock stopper with a sound level meter.

Conclusion........the stock one was louder?!?! Something about the spread of the sound waves with the GYT. The stock pencil hole focuses the sound waves, so it's louder directly behind the pipe. Overall the GYT was louder.

More power too! I like it so far, and if I have trouble with low end power, I'll consider the FMF Powerbomb header.

Thanks,
barton



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