Cool and cheers darlin
Excellent carburetors and so easily tuned. I had a set of side draft 39s on the GSX750R in my avatar. -BIG DAN:thumb: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:
The "Down Draft" carbs are pictured, with the blue velocity stakes. The red velocity staked unit is a "Side Draft" version.
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.Excellent carburetors and so easily tuned. I had a set of side draft 39s on the GSX750R in my avatar. -BIG DAN:thumb:
but putting a kn and not tune it makes the engine run bad?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.