Mikuni Flatslide Smoothbore RS-DK40's

CanDman · July 21, 2016, 03:50:00 PM

.......Looks like I fooked up again..........been looking to spruce up CanD's carb situation now that her bottom is done and it looks like I over did it. I have a brand new set (still wrapped in plastic) of these drag racing Carbs and I am looking to shrink. One dyno shop suggested to sleeve them down to 38 mm but not too many shops want to spend the time.......anyone have a practical solution? It looks like I will have to buy new carbs again...most likely the Keihin 38 flatslides (Frankie.....I wasn't paying attention..

) .......or if someone has another suggestion.....I am all ears.....

CanDman

JMR · July 22, 2016, 10:30:55 PM

Quote from: CanDman on July 21, 2016, 03:50:00 PM
.......Looks like I fooked up again..........been looking to spruce up CanD's carb situation now that her bottom is done and it looks like I over did it. I have a brand new set (still wrapped in plastic) of these drag racing Carbs and I am looking to shrink. One dyno shop suggested to sleeve them down to 38 mm but not too many shops want to spend the time.......anyone have a practical solution? It looks like I will have to buy new carbs again...most likely the Keihin 38 flatslides (Frankie.....I wasn't paying attention.. ) .......or if someone has another suggestion.....I am all ears.....
CanDman

40's will work....I have used them and found them better than the RS 38's if you can believe that. The FCR's are 39's....not much difference. I run them now and they are the bomb. I can cruise in 3rd at 2,000RPM smoothly and that is with some decent lift/duration cams.
Some TMR's would be great too......I just put a set of 36's on my CB750/1000 and am tuning them. The throttle action is fantastic....better than the FCR's IMO.

CanDman · July 22, 2016, 11:24:19 PM

Quote from: JMR on July 22, 2016, 10:30:55 PM
Quote from: CanDman on July 21, 2016, 03:50:00 PM
.......Looks like I fooked up again..........been looking to spruce up CanD's carb situation now that her bottom is done and it looks like I over did it. I have a brand new set (still wrapped in plastic) of these drag racing Carbs and I am looking to shrink. One dyno shop suggested to sleeve them down to 38 mm but not too many shops want to spend the time.......anyone have a practical solution? It looks like I will have to buy new carbs again...most likely the Keihin 38 flatslides (Frankie.....I wasn't paying attention.. ) .......or if someone has another suggestion.....I am all ears.....
CanDman
40's will work....I have used them and found them better than the RS 38's if you can believe that. The FCR's are 39's....not much difference. I run them now and they are the bomb. I can cruise in 3rd at 2,000RPM smoothly and that is with some decent lift/duration cams.
Some TMR's would be great too......I just put a set of 36's on my CB750/1000 and am tuning them. The throttle action is fantastic....better than the FCR's IMO.

Thx Jimmer.......I actually called up Gord Bush (Scott Goodyear racing mechanic who did the bottom end for the engine) and he said the same thing......as long as it is jetted properly he said they will work beauts !!!! He also said that the air flow needs to be increased by changing to pods....which he didn't like (says for my engine may prove a bit restrictive)......or strategic drill holes into the OEM airbox.........the good news is I can stick with them and just hang on for dear life after 8 grand.....

Thx for the good word......

CanDman
PS.......Snoay has the Keihin 38's so it will be interesting to compare the 2 girls very soon

JMR · July 23, 2016, 08:47:13 AM

"as long as it is jetted properly" Wise words. I have a Daytona (Wego lll) O2 sensor which really helps with tuning. The dyno is the final step.
I have used smoothbore and flatslides for decades and had great results. I always used individual K&N's on the RS's and FCR's. I put the largest I could fit which are about 4" long on the FJ.
The FJ is really nice for the individual filters as the sidecovers provide an "airbox". I have ridden in torrential rain and never had a problem with water logged filters. Same with powerful side wind. I can't say that about some of my other bikes.

CanDman · July 25, 2016, 05:31:39 PM

Quote from: JMR on July 23, 2016, 08:47:13 AM
"as long as it is jetted properly" Wise words. I have a Daytona (Wego lll) O2 sensor which really helps with tuning. The dyno is the final step.
I have used smoothbore and flatslides for decades and had great results. I always used individual K&N's on the RS's and FCR's. I put the largest I could fit which are about 4" long on the FJ.
The FJ is really nice for the individual filters as the sidecovers provide an "airbox". I have ridden in torrential rain and never had a problem with water logged filters. Same with powerful side wind. I can't say that about some of my other bikes.

That's great JMR.......thx for the great info.......did you have to do anything to the rubber sleeves for the intake manifold or were you able to use stock?
Cman

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