PineyPower
Well-Known Member
Getting myself a keihin fcr 39mm carb to support upcoming engine mods, just putting a little feeler out for tuning tips, upgrades, tricks, etc. from anyone else running one.
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Keihin fcr carberator tuning tips
- Thread starter PineyPower
- Start date
Help Support Yamaha Raptor 350 & Warrior Forum:
I got the power bowl on mine to help tune the accel pump.
PineyPower
Well-Known Member
Looked it up, that's a nice peice. Got any recommendations for jets? Not necessarily size because i know everyones got a different set up but even just a decent brand to trust?
YamahaNutz
Well-Known Member
+1 for the power bowl. It makes tuning the power jet very easy.
Stick with Keihin brand jets. Others vary and aren't consistent in size.
For parts
https://www.keihin-fcr.com
I met the owner once. He sells genuine Keihin parts for every part he can.
Couple tuning write-ups I found very helpful. Two are other forums, so don't know if it will stay posted.
https://www.braigasen.com/fcr_tuning.htm
https://www.yfzcentral.com/threads/the-mother-fcr-tuning-info-thread.129065/
This one has alot of knowledgeable members on the FCR. You can search the forum and find alot of info.
https://www.thumpertalk.com/
Stick with Keihin brand jets. Others vary and aren't consistent in size.
For parts
https://www.keihin-fcr.com
I met the owner once. He sells genuine Keihin parts for every part he can.
Couple tuning write-ups I found very helpful. Two are other forums, so don't know if it will stay posted.
https://www.braigasen.com/fcr_tuning.htm
https://www.yfzcentral.com/threads/the-mother-fcr-tuning-info-thread.129065/
This one has alot of knowledgeable members on the FCR. You can search the forum and find alot of info.
https://www.thumpertalk.com/
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Definitely use only oe jets in any carb.
PineyPower
Well-Known Member
Some damn useful info!
Any jet sizing guestimations for where to start? It's probably safe to assume the stock jetting for a 450 is gonna be miles off. I was thinking of getting a variety pack kinda kit for jets but holy hell there's over 100 for just the mains on that fcr site.
Ultimately I'm gonna use a wideband o2 to help me dial it in but a little extra help where to start is super appreciated!
Any jet sizing guestimations for where to start? It's probably safe to assume the stock jetting for a 450 is gonna be miles off. I was thinking of getting a variety pack kinda kit for jets but holy hell there's over 100 for just the mains on that fcr site.
Ultimately I'm gonna use a wideband o2 to help me dial it in but a little extra help where to start is super appreciated!
Where you at in jersey ? I was just thinking about getting yhe dynojet stage 1 , 2 kit there like 90$ look it up cause I'm getting ready too tune my 39mm fcr on my warrior kayden komraus friend me on fb we can bounce jetting off each other
PineyPower
Well-Known Member
I'm actually not on social media, but if you PM me here I check I often enough
Edit: oh **** you are right down the road from me
Edit: oh **** you are right down the road from me
Where you ? We gotta get together soon you going too rock j run in August
PineyPower
Well-Known Member
Pm sent.
48 /175
PineyPower
Well-Known Member
Got it in the mail, it's nice and clean and even came with some extra jets to play around with, im quite happy about that. I do have a few things, firstly there's a bit up near the choke looks like it's missing a piece
I've seen in pictures it has a plastic cap but otherwise it's a big ol shoulder shrug.
Secondly this didn't come with any of the many many hoses and even if it did, I don't know what's supposed to go where. Is it prettymuch all vents or do some have to go to vacuum?
I've seen in pictures it has a plastic cap but otherwise it's a big ol shoulder shrug.
Secondly this didn't come with any of the many many hoses and even if it did, I don't know what's supposed to go where. Is it prettymuch all vents or do some have to go to vacuum?
YamahaNutz
Well-Known Member
I think one of the articles I posted show the vacuum tube orientation. But all 5 of those are vents. You run 5 seperate vent tubes.
On mine from a YZ450F, that pic you have is the hot start, and choke is on the side of it in the other port. Hot start looks like a cylinder with a o-ring. Your plunger is broke off in it. Try to let it soak in a penetrant oil, and see if you can get it to wiggle out.
This is what was in there
If your going to soak it to clean it, try soaking it in whatever method your cleaning it before taking it out. Personally, I've been nothing but happy with boiling or using a ultrasonic cleaner. Chem-tool carb dip is what I used years ago.
On mine from a YZ450F, that pic you have is the hot start, and choke is on the side of it in the other port. Hot start looks like a cylinder with a o-ring. Your plunger is broke off in it. Try to let it soak in a penetrant oil, and see if you can get it to wiggle out.
This is what was in there
If your going to soak it to clean it, try soaking it in whatever method your cleaning it before taking it out. Personally, I've been nothing but happy with boiling or using a ultrasonic cleaner. Chem-tool carb dip is what I used years ago.
PineyPower
Well-Known Member
Oh alright I see the bit that broke there. It came with the metal elbow and the rubber boot too I figured it was something for the throttle cable. Weird the pictured I've seen have that capped off, I guess it was optional depending on what the carb came off. The nice thing about this carb is they used it in a **** ton of completely different machines
PineyPower
Well-Known Member
Anyone running the fcr use the hot start feature? Mines set for a lever but I dobt want to rout the cable and add all that extra complexity for a feature I won't use.
I got the old plunger out and replaced with a new cap,spring, and plunger set but I dobt have the cable or lever yet
I got the old plunger out and replaced with a new cap,spring, and plunger set but I dobt have the cable or lever yet
YamahaNutz
Well-Known Member
The yfz250/450f cable might be long enough. I used the stock choke cable from my Raptor 350. The choke lever on the handlebars is now a hot start lever. I use it. It starts way easier when the engine is very warm. I would have just left the stubby plunger on it with a knob but decided to use the old choke cable because I could. I had to heat and dent a releif in my gas tank, but shouldn't be an issue on a Warrior.
If you don't think you will use it, or don't want to, just put a vacuum cap on the tube. If the plunger stays shut, it will be fine.
If you don't think you will use it, or don't want to, just put a vacuum cap on the tube. If the plunger stays shut, it will be fine.
PineyPower
Well-Known Member
Yeah I used a little plug for the cap hole, I got the thing good and hot and so far every time it's fired right up. I bet if I was kick starting it might be a different story lol
One more question for people running the fcr... what throttle are you using? The warrior one opens the fcr to full using only like half it's throw, putting it in a kinda awkward position. I'm thinking of making a stopper of sorts to use the latter half of its throw for ergonomics but if a simpler solution already exists I'm all ears
One more question for people running the fcr... what throttle are you using? The warrior one opens the fcr to full using only like half it's throw, putting it in a kinda awkward position. I'm thinking of making a stopper of sorts to use the latter half of its throw for ergonomics but if a simpler solution already exists I'm all ears
I bought a yfz oem throttle seems too be good
PineyPower
Well-Known Member
We really gotta get together sometime soon lol, I'll trade ya tony beef for a tune
YamahaNutz
Well-Known Member
X2 on the YFZ throttle. My concoction wouldn't open it all the way. The YFZ450 throttle has enough throw to be a damn near perfect fit. I can adjust it to have just a little slop when released to make sure it fully closes and it goes WOT without putting stress on the cable.
