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miles on my carb:


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41mm Kehien FCR carbs are an optional replacement to the stock 1100xx CV's. There will be a reported performance increase with this flat slide smooth bore design. There will also be bike crafting involved as they are typically not designed to run with the factory airbox in most cases. That said, one of the tuners in Japan has managed to maintain a stock like install configuration which includes the factory airbox. They are less prone to the air flow dynamic's that present with the stock CV carbs installed to the 1100xx as they are a "direct lift carb" (Vacuum is not required to open the slides. The slides open via direct cable/throttle action). Having said all that, Sudco, which supplied these carbs to North American operators no long list them as available on their site. I scored a used set from a fellow forum member. If you go this direction ensure you find the "Down Draft" version as this is what the XX requires.
Couple of FCR install video's are linked below:

https://www.youtube.com/watch?v=B2g8lHVktwo&feature=related

https://www.youtube.com/watch?v=TBA5HfqLVqU&feature=related


The "Down Draft" carbs are pictured, with the blue velocity stacks. The red velocity stacks unit is a "Side Draft" version.



T.
 

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41mm Kehien FCR carbs are an optional replacement to the stock 1100xx CV's. There will be a reported performance increase with this flat slide smooth bore design. There will also be bike crafting involved as they are typically not designed to run with the factory airbox in most cases. That said, one of the tuners in Japan has managed to maintain a stock like install configuration which includes the factory airbox. They are less prone to the air flow dynamic's that present with the stock CV carbs installed to the 1100xx as they are a "direct lift carb" (Vacuum is not required to open the slides. The slides open via direct cable/throttle action). Having said all that, Sudco, which supplied these carbs to North American operators no long list them as available on their site. I scored a used set from a fellow forum member. If you go this direction ensure you find the "Down Draft" version as this is what the XX requires.
Couple of FCR install video's are linked below:

https://www.youtube.com/watch?v=B2g8lHVktwo&feature=related

https://www.youtube.com/watch?v=TBA5HfqLVqU&feature=related


The "Down Draft" carbs are pictured, with the blue velocity stakes. The red velocity staked unit is a "Side Draft" version.



T.
Excellent carburetors and so easily tuned. I had a set of side draft 39s on the GSX750R in my avatar. -BIG DAN:thumb:
 

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Excellent carburetors and so easily tuned. I had a set of side draft 39s on the GSX750R in my avatar. -BIG DAN:thumb:
Cannot argue with you on that point. Most everyone that uses them relates the same. Repair/replacement parts availability is very good also. I've stock piled multiple sets of Side Draft FCR's and a collection of CR-S (Round Slide) units for my older CB-F machines. Running 31mm CR-S on my 82 (slightly warmed over) CB-750F.

T.
 

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The jet kit that I have but have yet to install is a Factory Pro kit. It comes with enough parts to re-jet to various degree's depending on your level of modification, to achieve "best power". They produce three different kits depending on intended application of machine use.

Factory Pro: Producers of the EC997 Low Inertia Eddy Current Dynamometer Series and Quality MC performance products

It has been report that the one of the other jet kit producers, Dynojet, have adverse wear effects on the emulsion tubes of the stock carbs, when their replacement needles are used. There Jet kit info is here: Dynojet Jet Kits - Offering Motorcycle Jet Kits & ATV Jet Kits and they do a stage #1,2 and 3 kit.

Attached is some of the Factory Pro info include with the kit I have.

If exhaust system modification's are done and changes to the air filter are intended to a high flow or race type filter typically a lean mixture condition will result. It is normally a requirement that the jetting be changed to suit the new exhaust and induction system parts to cure the lean engine mixture condition. This area of performance modification is not something to enter into lightly. Full understanding is required to ensure that all requirements are met. To even change the stock paper air filter for a K&N re-usable type is to introduce a tuning change to the carb'd Blackbird. The stock CV carbs do not like when a K&N filter is installed with no other mods. The site search engine is your friend here. Many question have been covered many times. Use the site search and mountains of info will be available to you.

T.
 

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The simply answer to your question is; "If it ain't broke don't fix it." I have not done the Jet kit install because other modifications that would require the kit to be installed (like aftermarket exhaust system install) have not been done.


T.
 

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hi all,

Quick question,

If I change my stock filter to a KN sport filter and I change the stock cans to some dan moto gp cans without baffle, but keep the stock header, what modification should I bring to my carburetors? my bike is a 97 carburetor model
 

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The common reply to this question is: With "Slip-on replacement aftermarket mufflers installed you do not need to adjust the jetting." If your going down the road of the K&N install my advice, again, would be to not go there. The reported headaches and tuning issues are not worth the effort or the cost savings that having a "cleanable/reusable K&N filter" provides. But that's just me.


T.
 

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The common reply to this question is: With "Slip-on replacement aftermarket mufflers installed you do not need to adjust the jetting." If your going down the road of the K&N install my advice, again, would be to not go there. The reported headaches and tuning issues are not worth the effort or the cost savings that having a "cleanable/reusable K&N filter" provides. But that's just me.


T.
but putting a kn and not tune it makes the engine run bad?
 

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Yes. The K&N upsets the vacuum required to operate the CV (Constant Velocity) carbs. Time and time again the unknowing have done this simple filter install and met with performance issues like flats spots in the power at/above 4000 rpms and such. Search the site and you will read reams on "what happened when I installed the K&N" and the cure.."I re-installed the factory paper air filter element". This would be more the case if you are not one to wish to tinker with your machine to achieve good performance. There is lots of money that can be spent to have somebody else do this kind of work. Having spent the money to make the K&N work,..any savings afforded by it's install is very quickly lost. In my opinion the performance gains that are advertised from a filter alone are very much BS.


T.
 

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I'd suggest that you leave the bike as is and ride it. Put some miles on it. Enjoy it for what it already is. Spend you money putting fuel in it and riding it. Keep good tires on it. Then .... surf this site for what others have done. Increase your knowledge of the machine and then make choices on what you might like to do.


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Ive got 48000 miles on my 97 bird, my summer bird project will be just synching/rebalancing the carbs. If Im not able to achieve the results I want, ill just go with a good carb cleaning first. Its probably due anyway. Obviously it depends on their condition but the bike runs ok right now not great though.
 

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Running through the threads seen this one and I just swapped me engine out with a fi engine and have a set of carbs from my 97 engine sitting around I could sell for next to nothing if you have PayPal. Just message me if ever want any info on them or even want them.
 

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Does anyone know if you can get an airlock in your carbs? My bike has been running fine, then I removed the fuel tank and omitted to reconnect the fuel pipes to the fuel tap (don't ask why), so the carbs may have sucked air in when I tried to start the bike. It now will not start just pops occasionally. I have checked everything but nothing can get it going. Any suggestions would be gratefully received. Thanks
 
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