FCR's for not only race drive

[XTZ850 Rally Queen]

Hi, I'm from Poland and I apologize if I'm not making this clear, but I'm using a translator.
I've been reading a lot about FCR carburetors. I'd really like to add power to my motorcycle (I have a TRX engine installed in XTZ750). But I often use my motorcycle for touring, and I'm concerned about whether these carburetors are good for this type of use.( Not race only)
Will the fuel consumption be normal when easy riding?
Can these carburetors be ridden at lower RPMs without any problems? Are they not aggressive, like a 0-1 works.

From time to time, I like to use more power and which is why I'm thinking about the FCR39.
P.S. I already have Ignitech installed.

[HolerTogni]

Hi XTZ850 Rally Queen!

First, a heartily welcome to the forum - have fun here and in the real world!

Then, regarding the flatslide carburettors, I have to admit that I have very limited experience with them and I personally think they are not worth the (quite big) amount of money they cost.

But there are a lot of other people who really like them and will never go back to the original carburettors.

Since - sadly - here are not a lot of people active anymore, I'd like to direct you to the "German" TRX Forum, available at https://supertwin850.de/forum/

There are still quite a few people active that can help you.

You can as well dig through this forum here: The search works really well and there's plenty of information about Flatslide carburettors here.

Welcoming greets from Munich!

[dicky]

Personally I dislike flat slide carbs on road bikes.
The YZF750SP came with a bank of 4 FCR41's and it was an absolute blast on the track once you got all 4 carbs tuned and synced properly.
The same bike ridden on the road was a pain in the arse as keeping all 4 carbs in tune and sync was at best a compromise and sometimes worse.
When you tune for the track you know the conditions. When you tune for the road you don't know what the conditions will be like 100km from home.
Changes in air temperature, humidity, and pressure all have some effect on tuning. You can't always factor these in when touring, and tuning FCR's each morning before heading off on a days ride is taking away from time eating bacon, not my idea of fun.
If you only ride the same roads every day then maybe you can live with FCR's.
One the track FCR's are great, giving instant throttle response, as long as your hand is steady and you don't open or close a bit too far.
It is possible, and I have unfortunately done this myself, to stall the engine by cracking open the throttle too fast. Coming out of a tight corner and snapping the throttle fully open on a road bike with CV carbs doesn't have any nasty consequences. With FCR's you can end up on your arse.
FCR's can also be a bit thirsty, which is not a problem on the track but generally a bad thing on a road bike.
Others love FCR's, as Holer mentioned.
I think that standard CV carbs, correctly jetted, and with the Ignitech ignition, are the best option for the TRX.
Each to their own.

[BigAl-TC]

Hi,
I have had 41mm flat slides in my TRX for about 60000km.
Downsides = as Dicky said, if you snap the throttle open at low speed it will stall, you must roll the throttle open at low revs, above 3 or 4 thou it will take wide open, I don't have a problem on the road.
No choke makes it a slow start on cold mornings, sub 15 Celsius.
Fuel economy I have found little difference with mine unless you are giving it a good handful
A lovely responsive carb, I have ridden this across Australia with no problems what so ever.
Having said all this, I am changing this bike back to standard carbs simply for convenience of starting and having another bike with 41mm flat sides plus a lot of other hotrod parts on that.
With all that said, the standard carbs are great all round, but if you like to play with the bike a bit harder, go for it, at a price!!!

[XTZ850 Rally Queen]

Hi,
I have had 41mm flat slides in my TRX for about 60000km.
Downsides = as Dicky said, if you snap the throttle open at low speed it will stall, you must roll the throttle open at low revs, above 3 or 4 thou it will take wide open, I don't have a problem on the road.
No choke makes it a slow start on cold mornings, sub 15 Celsius.
Fuel economy I have found little difference with mine unless you are giving it a good handful
A lovely responsive carb, I have ridden this across Australia with no problems what so ever.
Having said all this, I am changing this bike back to standard carbs simply for convenience of starting and having another bike with 41mm flat sides plus a lot of other hotrod parts on that.
With all that said, the standard carbs are great all round, but if you like to play with the bike a bit harder, go for it, at a price!!!

Tell me, do FCR carburetors actually require adjustment several times a year, and for example, will I have to adjust them depending on the temperature?

I usually ride in temperatures between 10 and 30°C.

[BigAl-TC]

Hi,
I've never had to touch them since I had them Dyno tuned over ten years ago.
The only reason i'm swapping back to standard is I no longer do track days with this bike and think they are
a lot of money to hang off the engine and a choke is handy in the colder weather like you enjoy.
Don't get me wrong, they have been fun, I just enjoy the standard carbs for general use, and I have another bike
with all the bits for track days.
If you go ahead with them I think you will like them if you like to ride a bit harder.
If you want to know more, search on here for " cobbadiggabuddyblooo " Brian done a massive
amount of work on his and detailed a huge amount in this forum, a lot of very well thought out mods.
Also, Brian was advocating fitting 39mm flat slides or Mikuni 40mm flatsides May be better for your use ???
Best of luck and enjoy if you get a set.