Well after contemplating about it for a while, i went ahead and plugged the leak jet. It made a huge difference in throttle response. It pretty much eliminated the dreaded fcr bog. Here the details: as just about everyone knows I have a 470, the carb is a 41mm fcr off a 05 crf450 dirtbike. It came with a #55 leak jet. I havent tried any other jets in it. I used a small pencil torch and heated it up until solder flowed right into the jet. The reason i did it this way was several reasons: I was in a hurry and did wanna wait on glue or epoxy to dry , I can heat it up and blow the solder out if it made it worse, and it was super easy to do, and i didnt wanna worry about epoxy coming loose.
Now i can almost stab it open from idle and no bog. I have the idle set at 1300rpms. If i give it gas to 1500 or so and stick it, no bog! Before, I'd have to rev it easilt to 4500-5000rpm and then i could stick it. now i have yet to ride it, but it passed the neutral test with flying colors. This is what I have done in hopes of getting rid of the bog...first i adjusted the timing of the squirt..that made it better. Then instead of the oring mod, i bought a stiffer spring that does the same thing as the oring mod. it helped some. but the biggest difference was the plugging of the leak jet.

my buddies on there fcr carb solder the leak jet and then drill out the squirt hole to almost twice its normal size. and it makes a big difference. he said after cams and exhaust this carb mod made the biggest power gain. fwiw.

i'm a lil skeptical about drilling something that might not be able to be reversed tho. can you replace the squirter?

not sure but i know he used a little drill bit and plyers to turn bit becus u dont wana go to far. it can get better details if youd like. ill ask him if he remembers the size he used. i can contest that his bike had zero bog. he now runs the lectron carb since he stroked and bored his yfz 450 poor guy was mad when my z was beating him, its unfortunate that i still can beat him lol. not by much though. but hey winning is winning if by an inch or a mile its still winning.

well you can find out the details if you wanna, i'm open to suggestion. I still havent rode it yet, so it may be better than i think...who knows? I'm picking up barker drag pipe for it sometime this week. I talked to the guy today, so i'm interested to see if its gonna need tuning again. Of course i'm gonna try it the way it is and i'll bring the pipe with me to change when i go ride. (prolly labor day weekend) ANd i finally got my carbon fiber clutch...finally after 4 weeks!

you will be happy with the leak jet plugged, the throttle is real snappy right out of the hole.

o i can definately tell a difference...maybe i'll go ride this weekend....

if i plug my leak jet will i have to adjust anything else?
its a 440 camd intake exhaust and the fcr 8)
the bog makes it a pain to rid in the woods

what do you loose by plugging the leak jet?

I hit the "bog" a few times while racing this weekend...Cant stand it...

gonna have 2 bring it to me to get it tuned in 4 u LOL!!!

i dont have one so it dont matter , plus i got the adjustable accel pump to compensate, IMO those r a must have for any rider with an FCR carb. right now if i put my bike in neutral and mash on the throttle i have virtually no hesitation or bog it just revs immediatly and my idle is spot on.


if u just plug the leak jet u will put an exceptional amount of fuel through the spray hole and will problobly create the same bog but from flooding (im just guessing here)

R&D make sick accel pumps check them out.

Lol I might jus do that!!

Isnt the quick shot in the same line as the boyesend quickshot or am i way of? lol....

Ill check out that accel pump seemed to work wonders on your bike!

i think the "quickshot" he has is the adjustable one. I'm guessing you have it tuned where it is basically the same thing as plugging the leak.

You don't need to spend the money on the adjustable one if you can just tune it right with the jet. Plugging the jet will give you a bigger shot

im thinkin about getting the adjustable one jus so i can fine tune it.

ahh ok.. so its something in these lines I would need http://www.magicracing.com/RampD-Power-Pum...R41_p_4879.html

Instead of using http://www.magicracing.com/Boyesen-QuickSh...ver_p_1453.html

My bog isnt too bad... just got to keep rpms slightly up... but its still there.... ill live with it if i have to go buy a different pump cover! lol... A guy that i know races and he said it just hesitates on low end abit (I didnt really notice and not hitting the bog) but he has a good feel for those types of things and says its abit lousy until the revs picks up abit higher and thats when he feels the whole power... he said turning my fuel screw out 1/8 more would elimante it even more... should i try that or irelavent..? im taking my plastics off soon to do a good clean up... lost a few bolts here and there that vibrated off or have damaged threads... so im gona redo all that so shes all solid again... so while everything is off all fine tuning things ill try and do in the mean time!

I have no bog on my YFZ after jetting. Everything I read for jetting on my YFZ has them jetted a tad on the rich side. Maybe try that. I can punch it in neutral and get nothing but rev.

this is true. u can just change the jet and it does the exact same thing as my adjustable one, the only difference is that i can adjust it with just a turn of a screw Vs. tearing the float bowl off every time i want to try a different setting on it. its much like the zip ty fuel screw, just a much more simple way of tuning.

^^^^CAN SOMEONE DELETE THIS JUNK?????