fcr carbs

canappa · Post by **canappa** » Tue Nov 23, 2004 6:46 pm

using flatslide keihin on a fzr 1000 exup for street use is better a 39 or 41 size? im sure the 41 offer stronger high rpm power but it should also have less clean low and midrange, any suggestion? on rc model with 3.5 cc engine (.21 cid) we used 7mm on offroad and 9 mm for onroad, the 7mm offer better power until midrange and the 9 mm give better high rpm power but is also less responsive at slow speed and more difficult to tune. canap

cterror · Post by **cterror** » Wed Nov 24, 2004 12:32 am

the same goes for fzr as your RC model. Keihin recommends fzr 1000 91-95 to use either 37 or 39mm. i am planning to buy a set of 39 or 41´s, whishever i find first at reasonable price. it would be nice if i found a set of 39´s. according to internetbased very reliable sources (*LOL*), the 41´s are pain in the arse to tune up but i´m quite not buying it since FCR tuning guides are available and dyno-time is cheap. basicly.... id take either ones gladly to replase the notorious mikuni 38´s<img src=http://www.ezboard.com/images/emoticons/happy.gif ALT=":D">

ChuckD · Post by **ChuckD** » Wed Nov 24, 2004 3:20 pm

I'll get you quote on a set of 39mm. CHUCK D.

canappa · Post by **canappa** » Fri Nov 26, 2004 1:58 pm

thanks for your reply cterror, now it is clear that the right choice is 39mm size, tuning will not be easy anyway, but this site explain well: <a href="http://www.factorypro.com/tech/carbkei. ...  <a href="http://www.ansusa.com/How.htm">www.ansu ...  but my other question is: individual filter or stock eventually modded airbox with k&n? canap

Matt at PSB · Post by **Matt at PSB** » Fri Dec 03, 2004 4:53 am

41mm FCRs will be the worst purchase you have ever made for a FZR1000 Streetbike. Entirely too large & you will be VERY unhappy. 39 mm FCRs is pushing the envelope on a Streetbike in this application. You will have to ALWAYS be VERY careful to modulate the throttle inputs at low & the bottom half of mid- range RPM. If you make the mistake of whacking the throttle open at sub 4,000 RPM the bike will have a violent fit oscillating between bogging completely & violent power production about twice a second. No amount of tuning magic will address this problem. Your above 4,000 RPM performance will indeed be something to write home about. Sure you can re-program your right hand to mitigate much of this problem. This is the fine old school art of rolling on the throttle. FCRs are de rigueur on performance oriented FZR1000 Streetbikes. Realize that when one does a straight up comparison of 39mm CV carbs to 39mm FCR flat slide smooth bore carbs the FCRs flow approximately 18% more atmospheric gases into the engine. Using some mathematical extrapolation to illustrate what these different sized FCRs would mean: The 1989 & later bikes came with 38 mm CV carbs. We know that the FCRs equal approximate 18% more than the same sized CVs, so this gives us multipliers of 1.18 and its inverse of .82 to compare the CVs & the FCRs. Therefore FCRs X 1.18 = CVs, and CVs X .82 = FCRs. Using these equations: 38mm CVs X .82 = 31.16mm FCRs (no they do not exist) and 39mm FCRs X 1.18 = 46.02mm CVs (no they don't exist either). This means that 39 mm FCRs running though a stock airbox, in other words all other things being equal, is the same as having 46.02 mm CV carbs! I think you can see what the entire buzz is about with the FCRs now. Using the same extrapolating equation if we take the 41mm FCRs X 1.18 = 48.38mm CV carbs. Can you say “fugetabotit!” Velocity stacks add to the 18% advantage the FCRs have, but you would be EXTREAMLY UNWISE to run velocity stacks on a Streetbike! It is your money. It is your engine. It is your choice. If you understand the above equations you should quickly come to the conclusion that velocity stacks are more or less unnecessary. As for tuning of the FCRs after installation: Sure it is a good idea for maximum performance & maximum service life of cylinder head parts. Understand that I can have them set up to come out of the box pretty dam close to spot-on tuned. 19 times out of 20 the bike will run fine with straight-out-of-the-box carbs installed as is. Read that first sentence in this paragraph again. These FCRs are a big-ticket item; you should go to the trouble to have them checked on a dyno within the first month or 1,000 miles of installation. If you are fully up to speed on carb tuning then no dyno time required. Now for the money part: The rack of assembled & pre-tuned for you application 41mm FCRs retails for $1,150.00USD. The 39mm set retails for $1,070.00 and the 37mm set is No Longer Available (NLA). They come with push & pull throttle cables included. I sell the above brand new Keihin flat slide smooth bore FCR carbs for: 41mm at $1,092.00 per set, 39mm at $1,016.00 & 37mm sets are NLA. You pay shipping via USPS Priority Mail or International Air Mail Insured from me to you. You give me a Zip or Postal Code & I’ll give you a shipping quote. All major credit cards are accepted at PSB. FCRs are produced on demand in small batches in Japan. This means sometimes I can put a set of carbs together in a week and other times I have to wait 100 days for the ship to reach shore with the container full of FCR parts. Let me know what you are after & I’ll tell you within 24 hours the availability time line. References: Sure, Chuck D & at least one other member here have been doing Yamaha Genesis business with me for years. Please let me know if I can help you. The Japanese Yen & the US Dollar are doing weird things at the moment so these prices are subject to change. Matt at PSB (Performance Sportbikes, Missoula, MT., USA) Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... atpsb>Matt at PSB</A> at: 12/3/04 9:32 am

canappa · Post by **canappa** » Wed Dec 08, 2004 4:58 pm

Matt thank for the really tecnical explanation, i think it helped a lot to know that is a huge 18% air intake increase! there was several fcr on ebay and same may be temped to buy a 41mm thinking to have the better power possible....hope nobody from here have done this mistake! Sound a 37 will be the best option for a street bike without a big bore kit, maybe a 1040 or better a 1125 superbikemike kit will make full use of the 39mm even at low rpm. anyway i read by ducati user the 41 are for twins, so all you said make lot of sense, if a 1000cc twin use a 41 a four cannot! are you sure the 37 are out of production the keihin site still list them for the fzr. I cannot invest $1000 in the carbs at present but will keep your offer in mind cause is really tempting, having them setted up is the best deal, cause from what i have read is a pain without a good starting point.....but can them be used with the stock airbox and K&N or individual K&N filter need to be used on the FZR? is also possible the fcr give 10 hp increase? thx canap Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... canappa</A> at: 12/8/04 3:02 pm

Matt at PSB · Post by **Matt at PSB** » Wed Dec 08, 2004 8:18 pm

The 37mm set is discontinued from my supplier. Who knows what you can get straight out of Japan & who knows what that & Custom's Fees would cost. The hot set up on the CB1100Rs (No, that's not a typo.) is as follows: 1123 cc, 72mm bore X 69mm stroke, 9,500 to 10,000 RPM red line, with 39mm FCRs. This combo works fantastic on this engine. The FZR 1000 has a higher red line and when set up with a 1040 kit has a 77mm bore X 55.85 mm stroke. The five valve head breaths better than the 4 valve heads of the CB1100R and this is a good thing cause Genesis engines pay dearly in complexity & increased maintenance for that extra valve. This means that the 39mm FCRs work great on the FZR1040. The 1040 package is a fantastically functional set up anyway. Being mindless with the throttle application below 4,000 RPM is not allowed, but mindless people don't exist on a bike like the ones being discussed here for very long anyway. My parts catalog shows an adapter from the 39 FCRs to the stock FZR1000 air box. Due to the time of day I am unable to confirm this part is still available. I can confirm it at another time. Matt at PSB

Matt at PSB · Post by **Matt at PSB** » Thu Dec 09, 2004 11:45 am

Further research shows we are SOL on the FCR to FZR air box adaptors. Meaning they are NOT available. This means K&N pod filters are required. Matt at PSB

ChuckD · Post by **ChuckD** » Sat Dec 11, 2004 8:57 pm

I've been telling these guys about you for years Matt, thanks for giving the detailed anylasis, It was long overdue here. I thought that you could adapt the stock boots to fit the velocity stacks on the Airbox. Maybe we used a YZF 750 airbox when I did that mod years back? It would be intresting to see nonetheless. CHUCK D.

canappa · Post by **canappa** » Sun Dec 12, 2004 7:00 pm

Thanks for the further infos Matt and Chuck, the cb 1100 is a great bike, saw a beautifull one at an used bikes show last month, there was also a kawa 750 turbo in mint shape...... I think will add a big bore to my fzr in the future, nothing better than dispacement to gain torque at any rpm. the 39 mm is surely right for big bore application. about the airbox mount over FCR, yzf 750 one is too small, one guy that did the yzf 750 to 1000 cc conversion found that at 9000 rpm the 1000 cc stopped make power as it run out of brathe, putting the fzr exup airbox in the yzf bike solved the problem. maybe the thunderace airbox can fit fcr carbs. using the single filters will make a better power but this maybe require more tuning and money than a stock airbox canap

Post by **jjs777** » Mon Dec 20, 2004 6:25 am

great thread ...lots of info/advice -John 95 FZR1000 90 FZR1000

Post by **Hooligan** » Mon Dec 20, 2004 3:09 pm

so, for the carb guys out there (matt and chuck), is adding a set of flat-slides to my 750 something i should consider or is it a waste of time, effort, and money for a bike that will see most 70% of it's life on the street? one grand is ALOT of money, i would almost be inclined to put that towards a nice set of magnesium wheels and drop about 14 pounds.

Matt at PSB · Post by **Matt at PSB** » Tue Dec 21, 2004 12:56 am

Hooligan, you should go for the wheels. The FCRs are not an option on a FZR750 unless it is a 0W01. BTW a 0W01 with FCRs would not be a user-friendly streetbike. Now if it is a 93-98 YZF750R FCRs are the way it go. Question(s): You can get two Mag. wheels for a grand? You know somebody with a magnesium foundry? Matt at PSB

Post by **Hooligan** » Tue Dec 21, 2004 7:59 am

haha, no! i meant that 1 grand would make a nice dent in the cost of a set of magnesiums. that would buy me the front wheel and one spoke of the rear. my bike is indeed a 94 yzf750r, NOT an OW01. will i encounter ridability issues? i am assuming i would also need to get the bike on a dyno to have it fine-tuned...

Cosmo007 · Post by **Cosmo007** » Tue Dec 21, 2004 10:08 am

Hey Hooligan, I have had the opportunity to ride Matt's cb1100f with his stock carbs and his fcr carbs and I have to say that the fcr's were simply amazing. The only warning I got from Matt was to avoid whacking the throttle open at low revs. I followed this advice and found the carbs to be very responsive with easy rideability and great performance. I have been throwing this idea around in my own head for a year now, I just cannot decide if the fzr needs me to spend a couple more grand on her. Of course I would need the full Akrapovic as well, and don't forget the Falicon clutch basket to handle the 25rwhp improvement!!!! I feel like I am talking myself into this, never should have replied...<img src=http://www.ezboard.com/images/emoticons/sick.gif ALT=":x"> <img src=http://img.photobucket.com/albums/v209/ ... ng_sad.gif ALT=":sad"> I was politely corrected by Matt over a half-gallon of local Dopplebock tonoght. He does have smooth bore CR carbs, not flatslide FCR carbs. My mistake. but the essence of the post is still there. Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... osmo007</A> at: 12/21/04 7:50 pm

Post by **Hooligan** » Tue Dec 21, 2004 12:33 pm

thanks cosmo! the flat-slides were an idea thrown at me by another brotherhood member. if i was fortunate enough to own an SP, i wouldn't have to worry about fitting them as they were standard... right now, my bike is in pieces waiting to be put back together/upgraded. I was going to do a full on performance motor, but the cost is a big issue. especially on top of the other mods i am doing! one question, do you have to run a full system with the flat-slides, or is the exup unit acceptable? i have a brand new slip-on waiting in the box, i wouldn't want to ditch it. and finally, is the billet clutch basket interchangeable between the fzr1000 and the yzf750?

Matt at PSB · Post by **Matt at PSB** » Tue Dec 21, 2004 2:09 pm

No need to change the exhaust with FCRs. Billet Clutch baskets for YZF750s, how this works: I believe the Basket is the same on the YZF750 as on the FZR/YZF1000. I am NOT sure of this. In order to get a billet clutch basket you would first send me your existing clutch basket & its attached hub gear as a rebuidable core. The hub gear is transferred to a new billet clutch basket. So, even though I believe the hub gears are different from the 1000s & the 750s, I believe the baskets are the same. That would make this possible. The billet clutch basket are $439USD + postage from me to you. Matt at PSB

Post by **Hooligan** » Tue Dec 21, 2004 2:27 pm

matt, would i need to get the bike on a dyno to get the carbs properly set-up after installation? would i also have to ditch my stock airbox and run k&n pod filters, or is a stock box with a bmc filter the recommended way to go?

Matt at PSB · Post by **Matt at PSB** » Tue Dec 21, 2004 9:29 pm

No, you most likely would not "need" to have it dyno tuned. You might "want" to have it dyno tuned. The FCRs come out of the box very close to perfect if you provide enough & accurate set up info to me. 19 times out of 20 they run fine right out of the box. Of course very fine-tuning for your individual situation would further improve things. Additionally, understand that a dyno is just another tool that reduces the skill level required to fine tune carbs in a hurry. With sufficient skills an old carb tuning sage can do what a dyno does without a dyno. Pod filters w/o an air box. As a sideline, if you combine a well done 1040 kit with degreed cams & FCR carbs you have reached a state where you "need" a billet clutch basket. If the OEM basket were to fail catastrophically it would destroy the crank, rods, cases & trany. Another, completely different, situation in which you would "need" a billet clutch basket would be if you were somebody who had an inordinate fascination with wheelies. In that case you "need" a new clutch billet basket right now, with your stock OEM engine set-up, & in a couple of years you are going to need a new frame: Plan ahead! Matt at PSB Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... atpsb>Matt at PSB</A> at: 12/21/04 7:31 pm

cterror · Post by **cterror** » Thu Dec 23, 2004 2:01 am

Help me out guys, A guy nearby is selling out Keihin FCR40 ? carburators. They are rack mounted with yzf/fzr setup. The thing is... i do not know of any 40mm fcr´s. The type is KEIHIN FVKD 4HT GLO2. throats are front 40mm, rear 43mm. They have an TPS? type servo. what are these? and will they work as the FCR´s 39/41?

EXUP Worldwide

fcr carbs

fcr carbs

Re: fcr carbs

Re: fcr carbs

Re: fcr carbs

Keihin FCRs on FZR1000 Streetbike

Re: Keihin FCRs on FZR1000 Streetbike

Re: Keihin FCRs on FZR1000 Streetbike

Airbox Adaptors

Re: Airbox Adaptors

Re: Airbox Adaptors

Re: Airbox Adaptors

Re: Airbox Adaptors

Foundry Worker?

Re: Foundry Worker?

FCR rideability

Re: FCR rideability

FCR streetbike rideability & Clutches

Re: FCR streetbike rideability & Clutches

Fine points

Re: Fine points