OEMDirtBikeParts Reviews - Tips & tricks on FCR carb tuning the Needle & Air Screw

Рет қаралды 16,821

4 жыл бұрын

Easy ways to fix carb problems & tune for better performance.
Fine tunning Keihin and Mukuni Carburetors.
-FCR Fuel Air Screw Adjustments
-Keihin Needle Positioning
Rebuild service
oemdirtbikeparts.com/product/...

Пікірлер: 56

@arwiodense6222 2 жыл бұрын

Super great explanation. Love hearing great machines.

@dirtbikeplug 2 жыл бұрын

🥳🙌thankful

@bradcameron1376 8 ай бұрын

Great Video, what I need and nothing more. Thanks!

@Em6726 2 жыл бұрын

Love to see you do a video on an Xr650r build 🤘

@dirtbikeplug 2 жыл бұрын

If I can find a new leftover I would! Have had a few really like the 500 bikes atm.

@brendonbentley6617 2 жыл бұрын

Thanks, this was a very helpful video :-)

@dirtbikeplug 2 жыл бұрын

Like everyone were getting better with it!

@shadowV22 Жыл бұрын

The fact your exhaust is coloured like is a good indication the tune is correct ✅

@804jojo6 Жыл бұрын

my bike will bog out and cut off when i punch the throttle. and when i give it high revs it will cut off when it comes back too idle. i thought the bog was my accelerator pump timing or the diaphragm being worn out and i put a accelerator pump rebuilt kit and timed it right. it still bogs. u have any ideas on what i should do with the jetting/ needle.

@StumpStunter95 7 ай бұрын

Raise your needle up a lil?

@omarmorales4769 4 жыл бұрын

Hi Bro!, Again it's me with my NC250 chinese engine, 4 Valves, water cooled, comprenssion ratio: 11.5:1, bore/stroke: 77mm/56.3mm, Max power: 26hp / 9000rpm. I'm using a FCR37 (Is that ok? Or may be it's too big) Pilot jet: #40 and Main jet: #138. and 3/4 quarter fuel air screw out. It bogs when acelerate and hardly mid-range throttle response. My question Is... Is that the correct carburetor FCR37 i'm using?, if not would be a FCR33 be fine?, What else can change to get the correct tuning? Thank u in advance, regards

@norincobrocapri46 4 жыл бұрын

I would check the accelerator pump for correct operation. Then I would experiment with raising and lowering the needle height to see if there is an improvement in the midrange. Keep trying bigger or smaller main jets to get Full Throttle power optimised. Bog is lean. Stuttering is rich. I think OEM will say that the FCR37 is Not too big.

@RadekSkylark 2 жыл бұрын

Good vid, thanks! What do I need to do if I have popping on de acceleration as well as when the bike is hot rpms don't drop nicely to idle, they hang a bit just before idle and then drop eventually?

@dirtbikeplug 2 жыл бұрын

Fuel air screw adjustment and larger pilot 🥳

@grantas222 2 жыл бұрын

Having the same problem on crf250r it also bogs down when u quickly get on the gas

@grantas222 2 жыл бұрын

Do i need to richen the mixture?

@Newtimer49er 3 жыл бұрын

Do you guys set proper jets for different altitudes i'm in the mountains of TN and had a stock carb with jd i put in but really lookin to upgrade to a big daddy carb from you guys thinkin about the full exhaust also. Thanks

@dirtbikeplug 3 жыл бұрын

Hi Tristan, yes every order is already jetted to the spec of each order. Also, we have all additional jets sizes needed if moving from +- 3000ft elevation changes.

@veetwotls 2 жыл бұрын

Were the "R&D flexjets" work well (don't need be a contortionist to reach under carb for the screws) on adventure bike travelling various sea levels can adjust your AFR (fule/air) mix on the side the road without pulling carbs off

@veetwotls 2 жыл бұрын

R&D Flexjets come in 2 x lengths Shorter suiting single Keihin bikes (can use longer ones though) Longer suiting V twin Keihin bikes (harder too reach at carbs)

@zakokiller 2 жыл бұрын

I set my air fuel like you explained. But when i give it alot of throttle from idle it lean bogs. Does that mean i would need to raise the needle some?(move clip down) To give it more fuel right of idle?

@dirtbikeplug 2 жыл бұрын

Smaller pilot or could be many things like a worn throttle slide.

@zakokiller 2 жыл бұрын

@@dirtbikeplug so moving my needle Up making it richer would not help?

@veetwotls 2 жыл бұрын

CR 41mm FCR - V twin 950 Super enduro just installed a new set were pre assembled to suit my 35.5 sea level have them synchronized & idling ok On test ride bike runs fine on throttle but when i slightly start backing off (not fully closed throttle) it's loosing power like a bogging type feel (running out of fuel type feel ? ) with the K&N filter pods sounding like it gasping/kind of blocked sound any idea what too look for

@dirtbikeplug 2 жыл бұрын

Try without the pods, if it’s better get larger pods 😎

@veetwotls 2 жыл бұрын

@@dirtbikeplug Y a: NO LARGER PODS that will fit b: LARGER PODS WILL NOT FIT UNDER THE 950SE SEAT AREA - REAR CARB c: NOTING TOO DO WITH THE PODS d. same pods that are used on 39mm & 41mm been used since 2007 with success (inc my other 950SE 39mm FCR bike) from SUDCO c: issue fixed was a R&D Flexjet not correctly manufactured put my old set of flexjets on the carbs runs perfect just off idle were the in ballence was - see my vid on my channel

@veetwotls 2 жыл бұрын

kzfaq.info/get/bejne/m7aJn7CDv7ydnn0.html

@makoa2104 4 жыл бұрын

Good ole San Clemente 😁

@dirtbikeplug 4 жыл бұрын

We keep coming back, its a gem.

@norincobrocapri46 4 жыл бұрын

Gday. Re your TPS positioning. It looks as if it's turned anti-clockwise in the vid judging by the slot gap. You said to turn it clock-wise. Can you please clarify this for me, as it could just be my eyes! Thanks. Tony

@dirtbikeplug 4 жыл бұрын

ah, good observation if you were adjusting a 2002 and older fcr carb or some carb with the opposite arrangement yes you would go the other way to add advancement or richness on let's say a throttle body. This one is the way the clock moves to add more spring tension.

@desti6538 7 ай бұрын

Hello, which fuel petcock 1:42 do you use?

@dirtbikeplug 7 ай бұрын

On our site

@jessecrawford2711 Жыл бұрын

So I got a fcr39 finally,and I'm new to the tuning why does the idle speed up when I screw it in. Backwards of the cv I'm used to. Screw it in the idle drops. Running a 165 main 48 pilot apparently a emp needle haven't touched air jets and have no clue what they are. At two turns out on my first ride decel had no pops it was smooth but start up wasn't as instant as I like.. Take it back to 1 and a half turn as soon as button gets touch she is alive even at 35 degrees with the choke of course very strong all the way thru the rpm revs great power ups 1st thru third no problem pulls hard to ten grand. It's a 434 stage 1 hc powerbomb header 3x3.5 all the right adapters to mount it. No coast enrichment.

@dirtbikeplug Жыл бұрын

Purchased ours?

@norincobro6421 Жыл бұрын

Your pilot jet is slightly rich. When it speeds up as you turn it in, that means you are leaning out the mixture to a better AFR. What happens to the revs if you screw it right in ?

@jessecrawford2711 Жыл бұрын

@@norincobro6421I've got it straightened out you were right though pilot was way rich wound up with a 40 pilot

@jordanlogan923 6 ай бұрын

Interesting! I just scooped a used 2001 drz400e off a buddy a few weeks ago. Didn’t realize I might have been looking at Mikuni specs on that mix screw. I got a stock 45 pilot and it idles great at about 1680-1750 currently but you blip the throttle and it’ll surge and rpms hover around 2900 for a few minutes on its own and the eventual drop back down to idle. 🥲🤣

@mikecheeze4312 2 жыл бұрын

what size is your rear sprocket?

@dirtbikeplug 2 жыл бұрын

@jacobh707 4 жыл бұрын

I could really use some advice! I have a FCRMX39 and this thing bogs and dies if i snap the throttle. I cannot seem to fix it! Specs: exhaust is Fmf power core 4 with power bomb header. Air box has a large" hole cut in top. Stock S cams. Carb has O-ring mod done with tiewire. Carb and jets are clean. JD jet kit, 165 main jet. #42 pilot. Red needle clip 4th from top #4. I'm at 1200 ft above sea level. Accelerator pump spray stream is a strong diaphram in good condition. Just misses the slide without wetting it. And seems to spray for at least 1.5 seconds. It's killing me bro, any tips?

@ntme9 4 жыл бұрын

Try a 155 jet

@GEAR12117 2 жыл бұрын

Did you ever find out what it was? I'm having the same problem

@jacobh707 2 жыл бұрын

Never did : (

@motoweenies4431 2 жыл бұрын

@@jacobh707 You said the carb is clean, but did you ever redo the gaskets on the midbody? All of you're jetting sounds close enough to not have any serious problems with it. Edit: Your main sounds big, even for the mods, but just blipping it off throttle will hardly use the main jet at all

@jacobh707 2 жыл бұрын

@@motoweenies4431 I never changed the midbody gasket, the carb at the time was a brand new ThumperTalk carb. I'm not sure if I ever tried a smaller main jet, maybe thats worth a shot, but i HATE trying to seat the carb in the bike >.

@reptilesgamers00 4 жыл бұрын

What kinda exhaust is that?

@dirtbikeplug 4 жыл бұрын

Yosh Rs2

@itsstockmostly7012 4 жыл бұрын

What size main jet are you running

@dirtbikeplug 4 жыл бұрын

this drz400sm has cams, light head work & a 42mm carb- 188 main. all is important as if it was a stock bike I would run a 160-168

@dirtbikeplug 4 жыл бұрын

with this exact carb size that is, I'll say if ur running another size FCR carb on this 400cc engine- -36mm 145 main -37mm 145 main 39mm 155 main 40mm 160 main 41mm 175 main ETC.

@gubgub08 2 жыл бұрын

What about pilot on 41mm stock? And needle position?