View Full Version : FLATSIDES V CV'S
EFE 1230
14-01-2008, 08:17 PM
My EFE has gsxr cv's dynojetted to suit pods they work very well from idle to high rpm no flat spots ect. If I change to flatsides will it effect the way the motor makes its power as in flatten off the low end and push the "powerband" further up the rev range? Do flatsides run well at low revs? Do they change the way the power comes in (progressive to on/off)?
oldskool
14-01-2008, 10:27 PM
Flatslides give more instant power and dont need back presure to acdervate the slides cv's can be a bit slow on the up take and be less responsive than flatslides, slabby 750's came with them, out the box.
TurboKat
14-01-2008, 10:29 PM
I can only give you first hand experience on Std roundslide (non CV) vs Mikuni Flatslide on a big single (chalk & cheese) but I've just bought a new set of Keihin FCR 39s for the 9, if you can wait a month or so until I get 'em fitted, sorted & dynotuned, I'll have all the answers then ;)
If you can't wait that long, Deano's your man, he's back to backed CVs & FCRs on his trackbike.
Anecdotal evidence for a big bore 4 cylinder suggests the accellerator pumps on flatties make the biggest difference, you need to set the pump up carefully to make sure the on/off transition is as smooth as possible to avoid breaking traction or lightening up the front & running wide on corner exits.
I rode Deano's 11 for a few laps at Broadford with the FCRs & I can tell you that they're not forgiving like CVs, if I opened the throttle too far in too high a gear it bogged badly & I had to downshift to get the thing to pick up revs properly.
They sound the dogs bollocks at idle though, that rattling noise they make just screams POWER [:p]
Deano
14-01-2008, 11:03 PM
that was actually with the 750 darren and any more than 1/2 throttle under 8000 rpm and it would go backwards.
the 11 dosn't suffer with the lack of grunt down low or the bad bogging like the hot 750 did.
i think they are great for track use when the floats don't jam open.
response is excellent but if you crack the throttle from 0-100% then they can cough and splutter a little before the take off but not a problem on the track because smooth is fast.
they get my vote every time. not sure about for road use but great for track
and you cant go past the sound of open carbs on a bike bore bike.
zedsled
15-01-2008, 12:50 AM
I recently replaced the 34 cv's( that were kitted for pods) 0n my z1000 with mikuni rs34 flatslides, way better throttle response down low. Really notice the difference coming out of corners. I don't think you will be dissapointed. Got mine out of U.S. Brand new for $595us plus $60 for postage. Cheap horsepower. I think the fcr's are nearly twice that though
EFE 1230
15-01-2008, 04:56 PM
Food for thought, thanks guy's.
alfiestorm
15-01-2008, 05:25 PM
rs flat slides get e'm 38's I reckon will be right
Thruan
15-01-2008, 09:08 PM
:| here i am chasing my tail trying to get my bike to respond when i aggressivly open the throttle and its just a normal thing... oh yeah, 96 gsxr750 39mm keihin FCR flatslides.. mine have bin a real cunt to tune.. i still cant get the bike to idle respectably and consistantly, but im a little closer then i used to be.. but yeah i love them and i love the sound they make, cant wait til i get it running right and i get all my power back... starting to miss my turbo like top end rush :(
Zed14
16-01-2008, 03:22 PM
i have a set of 37mm cr specials if ya wanna buy em they are off a gsxr1100.
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