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Slight Bog at midrange? help !!!!!

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Hello all:

I have a 2008 DR650SE with the DJ kit 160 main

mixture screw out 2.5 turns, snorkel removed, FMFQ2 with the stock header

and the DJ needle clipped at 4th from top with no plastic washer, pretty much exactly what they tell you to do and the bike runs way cooler sounds fantastic starts and idles great and even rides pretty good but on occasion i get a bog on rapid acceleration like it is starving for fuel i actually thought it was out of gas so i hit the reserve went to fuel up but it only took 5 litres so that wasn't it if i don't WFO the throttle it is good but every once in awhile? is this a common thing do i just need to tweak something? any help would be great i am new to the jetting thing but not afraid to get my hands dirty and by the way this forum is truly Fantastic :rolleyes: :rolleyes: :crazy::bonk::thumbsup:

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there are a few mods that might help. In general I would say your slide is not lifting quick enough. Drilling a second hole in the slide should help (see keintech.com for pics) Jesse's sight also shows pics of opening up the top of the airbox. another thing would be to cut the slide spring down to reduce the sprig force and let the slide rise faster, if you have a few days read the DJ needle comparison novel and it will slowly explain the spring cut

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It sounds like you have the base-setup correct. Now you just have to figure out where the deficiency is. That "no fuel" feeling can also come from not getting enough air. With the FMF and a 160, i'm guesssing that it might need a little more air. Just for kicks (it seems you don't want to cut the airbox) take off the side of the airbox (4 screws) on the left side, drive it around the block or whatever and see if this changes for the better or worse (having the side off sounds and performs differently than it will with the top cutout... it will be louder with the side off, but the air increase should be noticeable) if this improves performance you should consider cutting the top, or filter holes or something.

If for some reason this has a negative effect, go back to the carb. Try the needle at different notches. And although drilling the slide is somewhat controversial as to how much it affects performance, it improved my and many others throttle response; though I doubt slide drilling will fix your mid range hesitation.

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Plug chop. Ride around a bit staying around the throttle range that has the problem, then cut the motor, coast to a stop and pull the plug. The colour will tell you whether you're lean or rich and then you at least know what to adjust.

Randy

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Thanks guys it is rainy out today and slicker than cat crap on a tile floor so i am going to tinker with the helpful hints and tips and i will run it in the morning i will post my results thanks very much

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Hello again i would like to thank everyone who replied to my plight, the rain let up and i removed the side cover and rode it around the block and the hesitation is gone YAHOOOO but i am not sure i want to butcher my airbox the bike is brand new and if for some reason something happened and i need warranty i am screwed? yes i think so, does anyone have any other option to get more air in? or should i drop one jet size until the warranty expires? thanks again everyone

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Yeap the air box cover has to be off as you found out.I did the same thing when I installed my kit.

I did not like having the air box wide open on the side either.What I did was take a dremel tool and neatly cut the center of the air box cover out leaving a thin strip up the middle.Then I took some UNI 3/4" thick large cell skid plate foam and cut it to fit the inside of the air box cover and glued it in place with a hot glue gun.

Best defense I could find for the area to prevent large debris from entering the air box.Helps prevent water from being sprayed directly into the air box also.

It may not do alot for protection but it made me feel better about it anyway.Kinda works as a prefilter I guess though.Easy to clean also.

If I decide to reverse my mods,the air box cover its much cheaper than hacking up the air box.Easier to install too.

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Yeah, you should drop a jet size and send me your FMF... until your warranty expires. HA!

Spare airbox? Probably costs more than it's worth.

Cut out the top with a laser at a 70degree angle, then when you go to the shop you can just put it back on like a lid.

I don't know man, but I wouldn't run it off road with that side cover off, or anywhere for that matter, the side #plate has a big vent directing everything right at your airfilter.

Ask your dealer if it voids the warranty. If they say NO then get it in writing, and go home and chop it. If they say yes it will void your warranty then send me your pipe and put in a smaller jet.

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I think i will have to do some talking to the dealer i bought it from but i do like the idea of modding the side cover as opposed to the box this is very easy to undo thanks blankwaffe and your pipe is in the mail nvdesert lolol thanks alot guys i am glad i was able to find out the problem now the fix is only limited to my imagination, great job people as i said this forum absolutely ROCKS

thank you thank you thank you

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I think i will have to do some talking to the dealer i bought it from but i do like the idea of modding the side cover as opposed to the box this is very easy to undo thanks blankwaffe and your pipe is in the mail nvdesert lolol thanks alot guys i am glad i was able to find out the problem now the fix is only limited to my imagination, great job people as i said this forum absolutely ROCKS

thank you thank you thank you

Unless you provide the same amount of air as removing the entire side cover you run the risk of being quite rich (as you found out) with the DJ kit installed. The DJ needle taper is much more aggressive than the stock BST needle to keep mixtures correct with the much greater air supply of the air box with the cover removed (or modded). The modded air box is the way to go. It's much quieter than removing the side cover, keeps your filter much cleaner yet provides all the air your engine needs. Throw a TwinAir foam filter in it and you'll have the highest air flow and best engine protection you can get. :thumbsup:

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another thing would be to cut the slide spring down to reduce the sprig force and let the slide rise faster

Technically cutting the spring makes it stiffer.

It'll have around 2mm less pre-load though.

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Well i bit the bullet and performed surgery on the airbox, the midrange bog is gone and it is hard to believe the difference in the entire range of power, when i used to gear down it would be jerky sometimes i could really feel the back pressure i am guessing? but now the whole range is way smoother so here is the complete setup and i am asking if I would notice a difference in performance if i went ot a 170 main?

K&N filter ( which i am replacing with a twinair its on its way)

160 DJ mainjet

stock header ground weld out smooth

FMFQ2 slip (beautiful enhancement it sounds so sweet)

:thumbsup: Air box snorkel removed and a bigass hole cut in the top

air mixture turned out 2 1/2 times from bottom

and the DJ slide needle no shim and at the 4th notch from the top

i would just like to know if someone has the same setup and if they are or have run the 170 jet and if it made any difference? but thanks all for the input i now have a "cooler" and snortier thumper and it was pretty simple stuff too thanks to all of you

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i would just like to know if someone has the same setup and if they are or have run the 170 jet and if it made any difference?

If you're 2.5 turns out then try the 170.

You can always put the 165 back in.

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SH650, just curious, but what elevation are you at, and how would you describe the humidity and typical temperature this time of year?

I agree with Nordieboy, if your out 2.5 turns you could probably run the 170.

Check your plugs first, clean them up, run the 170 for a while and see how the plugs look. The DR650 motor is extremely forgiving to carb mis-adjustments; I always think mine is running great... then I check the plugs after a ride or two and see that I was too rich or too lean.

Oh, did you ask the dealer about the airbox-chop voiding the warranty? Just curious as to what they said about it.

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Our elevation is approx 1200' and humidity is zip, i went to vegas last year and besides being 25 degrees hotter it was pretty much the same kinda of "climate as ours in the summer, we are pretty dry and fairly hot and no i steered away from my dealer i figured if it came right down to it and i was concerned i would look for another box before i sent it in but just curious as to what i can expect from the bigger jet? will i notice any improvement in power? or just a higher fuel consumption?

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I also have a 2008 with the same setup you are using I installed the DJ170 last night and I get one loud backfire and a flame with it on decel! Im guessing its too rich? Maybe some one can tell me. I guess I will try the DJ160 next.:thumbsup:

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Having the right amount of gas/air at said throttle position will give you the most power. You can only get so much with the BST carb airbox and a pipe. that being said, if the 170 makes the right mixture at the right time then yes it will be a gain in power; if it makes the wrong mixture, then it will just potentially waste gas.

For hot-rod like gains you'll need to step up to a different carb, compression kit/piston, bore it out, etc.

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I figured as much, i think i will stay where i am it runs like a charm although i can hear a small tappit sound at idle like valves are a little ticky i am unsure if this is normal or should i be thinking of an adjustment it is slight but i do hear them, i think i am a noise paranoid freak anything i hear that doesn't sound like i think it should i worry about it but the funny thing is i don't know what it normaly is supposed to sound like to funny

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