British Cust's CR Racing Carbs ????

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dawgenose

moped
I am considering ordering and installing British Customs CR Racing Carbs on my 2007 Bonne. BC Part Number BC801-002AR-AB

My question regards Gas Mileage. I have been told by a user of these Carbs his
Mileage has been reduced from 44 MPG to 28 MPG.

I would like to hear from other users of this carb set as to the mileage they are getting. My Bonne has a BC NARK and Preds and it too gets in excess of 44 MPG. I don't want to go from 44 to 28MPG.

Thanks for the help.
 
BlueJ

BlueJ

Blue Haired Freak
dawgenose said:
I am considering ordering and installing British Customs CR Racing Carbs on my 2007 Bonne. BC Part Number BC801-002AR-AB

My question regards Gas Mileage. I have been told by a user of these Carbs his
Mileage has been reduced from 44 MPG to 28 MPG.

I would like to hear from other users of this carb set as to the mileage they are getting. My Bonne has a BC NARK and Preds and it too gets in excess of 44 MPG. I don't want to go from 44 to 28MPG.

Thanks for the help.
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*sigh*

I've got stock carbs on my '07, and TORs, with no airbox and rejetting to match. I get 39MPG. It's the rejetting that will get ya - so, yeah, you put on carbs designed to get more fuel into the engine and your economy will definitely go down. You'll have fun getting there, though!
 
Easy13

Easy13

Street Tracker
IN ANSWER TO YOUR QUESTION, alot depends on how you ride the bike and what you want it to do. The CRs do a very nice job boosting acceleration and you'll definitely feel the difference, particularly in the low-end and midrange, where the bike spends most of its time. If you keep your fist out of the throttle your MPG shouldn't suffer much; the bike is the same, burning X amount of fuel in any given situation, you're just changing the fuel delivery method. My '07 never saw 44 mpg, even stock; 40 was about the norm. With the CRs and other mods (Epco exhaust, 790 cams, upgraded ignitor, DNA pods, etc), I'm averaging 35 mpg riding conservatively about half the time and not keeping my fist out of the throttle the rest of the time.

Despite the comments of the above naysayers (who have zero experience with these carbs), I've found the CRs to be very simple in design, easy to work with and tune, and they perform very well with a stock-displacement engine. Having no designs on going into the engine, they've given me excellent bang-for-the-buck performance.
 
mikenva

mikenva

Rocker
easy have you ever run good flat slides on your bike? So maybe you dont know what your missing ? Maybe you should try some you might find yourself saying why did i waste money on these toys lol.If you buy the best 1 time you dont have to spend more later.
 
Easy13

Easy13

Street Tracker
I've run TM Mikuni flats on a BMW, a Norton and even an old panhead. I've helped a friend set up some FCRs on his CBR XX dragbike. I've no doubt of the quality and performance potential of FCR39s. If you're going to bump up the displacement on a 790 or 865 Triumph engine, they're indeed a cost-effective system.

However, on a stock engine, the CRs are more than capable, delivering a much sharper throttle response than the CVKs, ease of tuning/maintenance, and a significant boost in acceleration. I've not dyno'd my bike, but the performance improvement is undeniable and it comes at a reasonable price. Bang-for-the-buck.

I'd also point out that the OP asked for gas mileage experiences with CR carbs, Not opinions on their viability.
 
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travellingtenor

travellingtenor

Scooter
If you are concerned about gas mileage flatslides or performance carbs are not the way to go. I have a flatslide on my DR650 and I have run them on my ZRX. The bottom line is this. Performance carbs eat more gas, period. Becides, why would you put performance carbs on your motorcycle and not want to twist the throttle a little? Makes no sense to me. Mod for performance and never use it? I have larger carbs on my ZRX and the larger carbs get better gas mileage than the stock ones. But, the carbs were modified and my system had many, many, dyno pulls before everything came together.
 
mikenva

mikenva

Rocker
A well tune set of flat slide carbs will get as good of milage as your stock cv carbs do.They are way more tuneable on these bikes .I got 52 mpg with the 42s when I had them on a stock 790.They only burn more gas if you run the bike fast.
It doesnt sound like he has bought the cr carbs yet so now is a good time to fill him in so he wont get suckered like the rest that buy cr carbs .SEAN only pushes them because no one at brit customs knows how to tune fcrs carbs.They dont know shit about makeing hp on these bikes since mat and them split up.
 
nohawk

nohawk

Rocker
mikenva said:
A well tune set of flat slide carbs will get as good of milage as your stock cv carbs do.They are way more tuneable on these bikes .I got 52 mpg with the 42s when I had them on a stock 790.They only burn more gas if you run the bike fast.
It doesnt sound like he has bought the cr carbs yet so now is a good time to fill him in so he wont get suckered like the rest that buy cr carbs .SEAN only pushes them because no one at brit customs knows how to tune fcrs carbs.They dont know shit about makeing hp on these bikes since mat and them split up.
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Sean and Brit Customs do know how to make a bike cool though.
I really would love to ride a 85 or 90hp Bonnie and see what its like, but the CR carbs have to be an improvement over the stock ones. I know that the stock carbs are the only thing keeping my bike from truely running smooth and clean. The CVK's just cough and fart too much. My old Thruxton did the same after chopping the airbox.
 
sportyone

sportyone

Street Tracker
nohawk said:
Sean and Brit Customs do know how to make a bike cool though.
I really would love to ride a 85 or 90hp Bonnie and see what its like, but the CR carbs have to be an improvement over the stock ones. I know that the stock carbs are the only thing keeping my bike from truely running smooth and clean. The CVK's just cough and fart too much. My old Thruxton did the same after chopping the airbox.
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that's what I've heard too, :shh: stuff around with a design too much that has taken many years of work to develop and you will get problems, just read some of the many posts of people on here that mod and stuff about with the original setup only to complain later about something not working like it should.

Bonnevilles are great bikes and are built to run for many years trouble free, they were never built as a racing machine or to try and complete with a ricer racer, they are a classic styled, exciting & wonderful bike to ride !
no other bike gets such attention when parked on the cafe pavement. IMHO :headbang2:
 
nohawk

nohawk

Rocker
I hear ya, but Im not bitching. I think the extra HP is much,much needed. Ive got my bike running as good as I can get it without an Air/Fuel analyzer or a Dyno and it pulls good and strong but every now and then it'll spit back or idle speed will change a little. Gives it a bit more personality I guess but I know better carbs are the next logical step. Ive never ridden a Bonnie with flat slides but Ive had some Honda XRs with them and compared to Constant Velocity carbs the throttle response was far better but CV carbs have advantages too.
 
mikenva

mikenva

Rocker
You can build these bikes to run way better then stock but you have to tune them right when you do so.Anything above idle on my 1087 is way smoother then a stock bike.IF you ride it normal the extra power makes it easyer to ride ,going down the high way its has power enough you dont even know its running .So you can take a cool bike and make it better.
As far as the cr carbs go look at it this way even cr carbs are not cheap .You are better off buying the best the first time that way you can forget about buying carbs from then on.You see alot of used cr carbs for sale you dont see many fcr carbs for sale and I think there are more fcr carbs on these bikes now then cr carbs so that should tell you something.The first ride you take with good flat slide carbs on these bikes you will think you added a turbo to your bike its night and day how good the bike runs with them.
I know the price of flat slides scares alot of people off but just add up some of what other mods have cost you for your bike no other mod with make the change the carbs will.
 
mikenva

mikenva

Rocker
sportyone said:
that's what I've heard too, :shh: stuff around with a design too much that has taken many years of work to develop and you will get problems, just read some of the many posts of people on here that mod and stuff about with the original setup only to complain later about something not working like it should.

Bonnevilles are great bikes and are built to run for many years trouble free, they were never built as a racing machine or to try and complete with a ricer racer, they are a classic styled, exciting & wonderful bike to ride !
no other bike gets such attention when parked on the cafe pavement. IMHO :headbang2:
Click to expand...
most of the design put in these bikes was do to the bottom line not to make them run better.
 
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