CAN ANYBODY TELL ME ANYTHING ABOUT THIS F2-RACING POWERBACK SYSTEM? DOES IT ELIMINATE THE BOG PROBLEM TOTALLY? ANY INFO WOULD BE GREATLY APPRECIATED.

found this over on yfz tech.



Where the rubber o ring is i put a small zip tie instead because there was still play in the little lever when i punched the throttle real qiuck with the rubber ring ( it would streatch). I am running a 45 pilot and 35 leak jet with the ac pump screw turned OUT i think half a turn or alittle more. The bog is totaly gone. The way it runs now is friggin amazing with no bog.

THANKS ALOT. ILL GIVE IT A TRY. TRY ANYTHING AT THIS POINT!

or you can buy the R and D power pump which has a adjustible leak jet and a upgraded stiffer spring so you dont need to do the o-ring mod.....mines completely gone also but i have also gain alot in throttle response

what side of the carb is it on and under what ?

dang i never saw this thread before, and just used a zip tie to begin with. just for the fact that o-rings are rubber, and stretch, so i just zip tied it. good stuff man. my bogs gone too. between that, rejetting, more air flow in to create more vacuum in the cab, and the leak jet. my bog is pretty much gone.

I agree with 350....I bought one and I LOVE it! It pulls harder and faster!

what side of the carb is that located on. i dont think i am going to remove the carb from the bike to try this out.

you dont have to remove the carb to mess with the accelerator pump linkage. its in the throttle assembly. just take the cover off the throttle assembly.

THANKS ALOT. WORKS GREAT. WENT WTH A 162-MAIN, 48-PILOT, AND A 35-LEAK. A GOOD MATCH WITH THE HMF. RUNS AWSOME!!!

whats ur elevation?

sorry took so long. 1800 ft.

the bog is caused by improper tuning. Or maybe a low-quality exhaust. (this includes Nmotion) simple really.....

idk thnk you can blame it on the exhaust, people have the bog with every exhaust. THe bog is present with the bike in full stock form

What are some high quality exhausts?

lmfao, nearly everyone on here would love to get their hands on an nmotion especially if they werent so loud. Guess quality doesnt matter to any of these people.

I dont wanna argue with anyone on here, thats not what i was aiming for. Eveeryone on here wants an Nmotion, but everyone on here seems to have "the bog" problem also, so whats that tell you??? I dont have a problem with bog, but i did with my Nmotion even after having the carb apart like 20 times trying to tune the darn thing. HMF has been the most user friendly exhaust i have ever owned. It took 3 trys, and my tuning is perfect. I dont have the issue with the bog. I also know TC is a great exhaust. Sparks are junk (however they make good power), Nmotion are junk (also-make great power but bad tuning) thats my personal experience. You have to look at things other than power. If you want an Nmotion so bad, then dont complain when the bike has a bog.

Also in stock form, the YFZ is tuned TERRIBLY WRONG. So of course its going to bog. Once you take the airbox lid off, its kinda close but still a little off. You dont need any fancy carb bolt ons for proper tuning (or to eliminate bogging). It just takes time and patience. Once again, i dont have ANY BOGGING WHATSOEVER

You are right about the tuning on the nmotion pipes i have heard that form several people. I'm just saying the bog is not a result of the exhaust being poorly made. The nmotion and some other pipes require leaner jets than most pipes in some peoples experience which is probably why they are more difficult to tune because people dont knw where to start. I had the bog with my stock pipe, stock jetting, then with baffle out stock jetting, baffle out rejet, and i had it with my venom and rejetting

I did the carb mod with the ziptie and adjust my idle up just a tad higher and now i have removed 95% of the bog. The other small part im sure i can get rid of with a change in leak jet.

If the bog was the result of an exhaust then why would the R&D pump with adjustable leak jet cure the problem?

The jetting from the factory is just not correct from what ive read and studied.

Im not trying to argue about this either so this is my last post on the subject

sorry for even starting anything

The bog is when you stab the throttle, the accelerater pump has to catch up to the throttle because they're connect with an o-ring, which gives it that second or two of hesistaition before it catches up.
Thats the only culprit to the bottom end bog. There is no such thing on my Honda. and on my brother's YFZ it is terrible. Simple fix really.

Chadkrash what the hell are you talking about, at least understand the dynamics before you go to false claiming.

Sparks a bad exhaust, I guess that explains the intense popularity. I have ownde one and it was a very nice unit that was simple to tune. I would like further explanation of why its a bad exhaust.

about the o-ring bigjosh when i opened mine up yesterday it didnt have an oring on it. I think that is maybe what they used to in place of a ziptie when they did the mod? idk mine didnt have one but maybe it fell off or something. when you get a chance you should do the mod

Sparks may be easy to tune, but they are made of light materials. Once they get hot and after some time of being rattled around i have seen (on multiple occasions) them blow a hole straght out the side of the muffler AND the header. Nationals will really tell what your machine is made of, some of you will NEVER see any of this happen because you are not bashing your bike as hard as some of us. And Bigjosh, maybe you should understand before you go opening your mouth... I DONT HAVE A PROBLEM WITH THE BOG... so i guess my carb is built different than every other yfz carb on the planet...As for everyone's bog problem, Maybe a leak jet change will fix it. but guess what, THATS TUNING!!!!!!

ALSO its not fuel injection so throttle response is not going to be instant...

you blamed the bog on the exhaust and its tunability. When in all reality it is the yfz carb and components that are the culprit. Maybe you dont have the bog, good for you so in that case you knw nothing about and can't say what it is or what causes it right. So if you dont have the problem and you have the perfect exhaust and carb then you shouldnt be giving any advice and that being said dont belong in this post at all. so bye.

Obviously you didnt read very thouroughly....I HAD THE BOG at one point. Stock bike- BOG IS TERRIBLE. Take the airbox lid and baffle off, and its close to being right. So then you go out and buy an exhaust and you have the problem allover again...

I HAVE NEVER BEEN TREATED LIKE SUCH A JERK WHEN I WAS TRYING TO HELP SOMEONE SO F*CK EVERYONE OF YOU

I was simply trying to guide you all in maybe a better direction...But you all act like a bunch of crybabies like i was calling you stupid or something. I was sharing my experience and thats what this forum is for so kiss my a$$

it is a jetting problem which you deal with when you have a carb. Its not any particular exhaust bro thats all im saying, every change in exhaust intake etc is going to require a jetting change.


Im not trying to be a jerk but you arnt making much sense. Think about it if the stock jetting is already lean, then you take baffle out and airbox lid off you gonna bog way worse unless you rejet. thats just the facts of jetting. Add aftermarket exhaust to that without rejetting and your motor wont last long.

The bog is a tuning problem for the carb and accelerator pump components. It doesnt have anything to do with exhaust being a bad or good exhaust, so when you say that of course you will be corrected. Dont take it too hard man I'm not trying to be a dick or make enemies just letting you knw.

i said it was a problem with tuning....And maybe a junk exhaust. Junk exhausts are HARD TO TUNE thats what i meant by that.
In my experience, A stock yfz ( im on my 3rd one) comes rich. Ive neevr got one that came lean from the factory.

its cool you didnt say anything that was out of line but other people did. I was sharing my experience. thats all. And besides, they use these carbs on other things than YFZs. Its not like this is an exclusive carb. Keihn builds carbs for lots of bikes and brands and as a matter of fact isnt it a Keihn thats on a 450r???? (correct me if i am wrong) I realize they are not identical models, but the same idea.

if a stock yfz comes rich then someone please tell me why everyone is running 160 plus main jets? stock is a 155 if im not wrong which i could be. I knw for a fact that everyone puts richer than stock jets in their 450s when they rejet unless they are in major altitude. They come stock with like 155m/42pilot.

I can understand where you are coming from with an exhaust being difficult to tune but that is because they have different airflow from some of the other exhaust and not because they are junk. These exhaust you are mentioning sparks, nmotion are some of the top performing exhaust maybe just maybe there is a reason they are having to be tuned a little diff?

Anyways aslong as you dont have a bog then its all good. The R&D pump does more than just cure the bog at increases throttle response aswell. Its not a bad investment at all and I myself am thinking about getting one here soon.

all of my yfs have came with a 45 pilot from stock. And the reason for putting in a little fatter main is because it adds to the top end power. The main jet has NOTHING to do with "the bog"... Thats all in your pilot/needle setup. And another thing, when you buy an exhaust just because they tell you to run certain jets, doesnt mean its going to be EVEN CLOSE. Nmotion told me to run a 50 pilot and 170 main. And they told me to leave the needle alone... Well all YFZs dont come with the same needles, jets, etc. So them telling me to leave the needle alone is wacko because they didnt even know what was in it. My 04, 06, and 07 have all come with needles that were so different, you could tell with the naked eye. The leanest needle i ever got with one (also adjustable) was my favorite With the Nmotion. But still, no-matter what pilot i had, it always had "the bog". My point is, without proper tuning, you will never get rid of it all together. If you wanna buy an adjustable leak jet thingy, go right ahead, im just telling you there are ways around it but it takes time and patience.

Also, read on ANY jet kit, even dyno-junk, K&N, etc. and they all say something about "this only helps with a well-made exhaust" or something along those lines. Just because it says Curtis Sparks on it, doesnt make it a quality part-trust me on that one... And if Nmotion is soo good, why did they sell out or whatever happened to them?? Guarantee the company that makes them now will change something for the better...

Also, read on ANY jet kit, even dyno-junk, K&N, etc. and they all say something about "this only helps with a well-made exhaust" or something along those lines. Just because it says Curtis Sparks on it, doesnt make it a quality part-trust me on that one... And if Nmotion is soo good, why did they sell out or whatever happened to them?? Guarantee the company that makes them now will change something for the better...

the yfz doesnt come with a 45 pilot stock maybe your stealership put it in there. I didnt say the main jet had anything to do with the bog. But the yfz's are jetted a little lean ask anyone. The bog has nothing to do with the pilot needle it is the leak jet and accelerator pump and ap squirt timing. I knw the exhaust come with jets sometimes and thats for an average jetting they arnt always going to work for your quad.

the ways around it are tuning your carb which means changing leak jets and adjusting your ap squirt timing. dude you can do all that with the r&D so why not buy it. your way around it is just stating everything i said. tune your carb. THE BOG IS NOT THE EXHAUST. lol

I have a low quality nmotion in fact there so low quality I have two of them. Yes I like low quality that much. And I have zero bog. I got my jetting close and put in a leak jet and zip tie not hard or expensive at all.



Your an idiot and ASSume things that arenot true about Nmotion pipes.

MayBe i think your a Fu*kin idiot for owning an Nmotion (let alone 2 of them) , because their customer service is terrible and thats what its aallllll about. I understand that the leak jet has to do with the bog and so does the Pilot jet. Im glad you got your Nmotion tuned for your bike, I SAID I COULD NOT....

dont be mad at me because i said Nmotion is junk.... Just ask anyone that Actually knows what they are talking about, then you could be mad at alot of people. And i cant think of any reason my dealer would have put a 45 pilot in my carbs, and besides i bought them from all different dealers (whoever had the best deals going on at the time). I actually lied to you, the 2004 had a 42 pilot in it and my 06 and 07 came with 45s.

well i can see this topic getting locked soon. lol

To solve the bog you need to tune your carb right thats it. You can do the zip tie mod and change the leak jet or you can by the power pump which does exactly both of those things minus using a ziptie. Thats the cure.

Run whatever exhaust you want lol its not gonna help or hurt your bog if your jetted correctly.

Nmotion pipes will definately blow hmf out of the water in the performance area. I would gladly spend an extra hour tuning my carb for a junk nmotion and be two quad lengths ahead than run an hmf and get hit in the face with roost.

yah lie once lie everytime lol, nah if the dealer jetted the quad before he turned it over for you maybe because he couldnt get it to start easy or something that is probably the reason they came with 45's.

My 08 came with a 42

chadkrash382 I dont care what you think of my choice in pipes and I am only mad about you ruining a good thread.

[quote name='Stix1107' date='Jul 13 2008, 07:18 PM' post='689050']
well i can see this topic getting locked soon. lol

To solve the bog you need to tune your carb right thats it. Thanks...crooks, your a jerk, and very, very ignorant(the dictionary definition- please read if you do not know...)

All you gotta do is take the time to tune your bike. Everyone puts things on and gets so excited to ride it they don't care if it runs like crap.I had the bog when it was stock, but I beefed up my jets and it semi went away. I put a 65 pilot in my bike, with an Nmotion, and the airbox lid off and it pulls hard all the way through with no bog. Then just keep up with your jetting through the seasons. I've never done any mods to my carb, put any extras on it, and it's an 05.

Mr. Crash I am sorry if I upset you.
I heard it right out of the mouth of Dustin Nelson, my friend so ya they is a lot of truth to my statements. I dont think they're is an o-ring it's the slack, that allows the accelerator to fall behind when you stab the throttle. We are doing the mod this week and finalizing the tuning on my brother's YFZ. So I will let you know how well it does for us.

all yfz's come with 42 pilot stock my 06 did new.

ok and i guess you know what needle ALL OF MINE came with too dont you?? im done with this thread... I guess its pointless to make anymore posts because people think i lie or something??why would i make up what jets my bike came with?? GROW UP

well actually we do knw wat needle each year model comes with bro. lol

ok so i got to the lever and I dont even have an o ring?? am i supposed to have on there? should i still put a zip tie on it?

no it is not supposed to have an o-ring just zipty that baby and your good to go.

ok thanks. I tried to before, but I need some smaller zipties. I'll try to get some pics for people who need them.