New keihin flat slide carbs

xbacksideslider · Sep 29, 2011

AussieCombat said:
Couldn't you go straight across from one tap to the other, with a T piece in the middle, straight on to another T piece,
forming a H pattern, then down to the Carbs.
AC.

Yes, that's how mine are now, except I do not have 90* coming out of tank. Mine lines drop straight down, curve and meet in a T in the middle, then continue as a single line to above the carbs where there is another T. Yes, an H pattern.

1up3down · Sep 29, 2011

Vintage Paul, I think your friends are steering you wrong.

I have had the flat slides for 18 months now, and my bike starts first kick. Where did you get the concern from anyone reporting here that they do not start a bike every bit as easy as any other carb set up?

Sweet running? You think you would somehow lose that if you put on a good set of carbs?
That is the whole purpose, to have a set of sweet flowing carbs.

My bike is stock, just like yours, and I would guess almost everyone else who has bought them.
Why would you think that only "performance" orientated, presumable hotter cam,etc, bikes would benefit?
ALL bikes benefit from a set up of good twin carbs, box stock or not.
Stay with a single Mikuni if your want to plod about, some of us like to open the throttle just a wee bit.
These are not extreme, or "hot" carbs, just a set of well set up, bolt on, very good carbs at an excellent price considering manifolds, filters, cables, etc come with them, that's all.

Carbonfibre · Sep 30, 2011

There is an awful lot of rubbish talked about carbs, but the Keihin pattern flat slides are far superior to anything made by Anal, and will provide improved performance, fuel economy, and increased reliability. Choice here is really a no brainer, unless you are wanting to retain original appearance, and are not concerned about carbs which wear out pretty quickly.

gw88 · Sep 30, 2011

geo46er said:
Hi gw88,
Not being picky, but you have your fuel filter installed backwards.

GB

Hey GB, thanks for the heads-up. Never realized the filters only goes one way. You are right-on! Have now switched it around. Most observant of you - cheers.

gw88 · Sep 30, 2011

jseng1 said:
Hey gw88
What kind of aircleaners are those, model # etc?

Some of the air cleaner clamps come to me supplied with the carbs, and yes - somethimes I supply the convenient hardware variety.

Hi Jim, air cleaners purchased from Mikes XS (Canada) www.xs650direct.com Part #15-0035 @ CAD $15.68 each + Shipping.

chapmanmd · Sep 30, 2011

I have the Keihin FCR's on my Thruxton. I sure wish Keihin would make these small enough for Norton use.

pete.v · Sep 30, 2011

gw88 said:
Hi Jim, air cleaners purchased from Mikes XS (Canada) http://www.xs650direct.com Part #15-0035 @ CAD $15.68 each + Shipping.

That is a great tip. I have purchased items from MikesXS many times (master cylinders, breather valve etc.) now I know where to get rebuild parts and jets for these carbs. I may get a couple of needles just to see if I can rework them as JS does, delicate work to say the least.

For anyone getting these unit, it is advisable to go through these and check them over carefully. For instance, the jet holder on mine was a little off causing the needle to bind which would not allow the slide to drop smoothly to the stop. The float bowls are quite fussy and require a deft and ginger touch to remove the bowl. Once off, the jet holder has to screws holding it in place. There is an O-ring in there that needs to be just right. Don't over tighten and check your work.

For anyone savvy enough to run these, you better be savvy enough to get to know them. I guess this goes for Norton in general.

Make no question about it, the effort is well worth it. Yowza, I got a RED HOT Norton. A thanks to Jim Schmidt for offering these great products. Play that Sax Jim!

pete.v · Sep 30, 2011

chapmanmd said:
I have the Keihin FCR's on my Thruxton. I sure wish Keihin would make these small enough for Norton use.

Are you really running open headers on that bike? How's about a sound bite?

jseng1 · Sep 30, 2011

gw88
Are those aircleaners $30 a pair?

pvisseriii
I now go through each carb carefully before they go out - checking for needle bind is one of the things on my list, along with float height & everything else. The needle jet body can be aligned by loosening the torx screws and levering the needle jet body in the necessary direction with a screwdriver, then re-tighten.

I prefer the idle mix screws to be between 1/8 and 3/4 turn from closed. If they are beyond this then I recommend changing the idle jets (smaller = less screw opening). I send out what I think is best but sometimes a particular carb or motor is a little different.

pete.v · Sep 30, 2011

jseng1 said:
gw88
pvisseriii
I now go through each carb carefully before they go out - checking for needle bind is one of the things on my list, along with float height & everything else. The needle jet body can be aligned by loosening the torx screws and levering the needle jet body in the necessary direction with a screwdriver, then re-tighten.

Yep, that's just what I did.

hudson29 · Sep 30, 2011

1up3down said:
I have had the flat slides for 18 months now, and my bike starts first kick. Where did you get the concern from anyone reporting here that they do not start a bike every bit as easy as any other carb set up?

Sweet running? You think you would somehow lose that if you put on a good set of carbs?
That is the whole purpose, to have a set of sweet flowing carbs.

My bike is stock, just like yours, and I would guess almost everyone else who has bought them.
Why would you think that only "performance" orientated, presumable hotter cam,etc, bikes would benefit?
ALL bikes benefit from a set up of good twin carbs, box stock or not.
Stay with a single Mikuni if your want to plod about, some of us like to open the throttle just a wee bit.
These are not extreme, or "hot" carbs, just a set of well set up, bolt on, very good carbs at an excellent price considering manifolds, filters, cables, etc come with them, that's all.

Thanks for this assessment. Carbs can be a bit if a voodoo science, one that is poorly understood by many of us. We hear lots of opinions, often from folks who had problems they never solved and often from "experts" who have never had any experience with the setup being discussed.

I recently purchased a supposedly turnkey Mikuni conversion kit for the SR500 that has turned out to be a real problem, one that is still not fully sorted six months on. I'm sure I'm not alone in this, many of us have bought upgrades that turned out to be disappointments. Your words help sort the wheat from the chaff on this one.

Vintage Paul, still pondering . . .

Carbonfibre · Sep 30, 2011

Float bowls are very easy to remove on these carbs............after taking out the fixing screws, simply lift the float bowl off angled upwards higher on same side as fuel inlet. Bowls need to be replaced in the same way, as the floats can get tangled on the atmo tube fitted into the bowl otherwise, and fuel level will be wrong or floats may jam. Also if you need to remove the main jet holder for any reason, make sure the needle jet which is held in by the jet holder doesnt fall out and get lost...........

gw88 · Sep 30, 2011

jseng1 said:
gw88
Are those aircleaners $30 a pair?

Jim, according to their price list, yep.... Check it out.

ashman · Sep 30, 2011

Hi All

Thanks for all the pics, I have the carbies set up on the Norton now, fuel lines on, started on 2nd kick, turned the idle screws down as they were running to fast, tuned the air mixture till they were running smoothly (about 2/8 of a turn out), reset the idle then turned it off to put my riding gear on.
Bike started first kick with ease, took it out for a test ride, running very smoothly, slite missfire midrange, may have to lift the needles up or reset the air mixture, when I got back home went to adjust the left idle screw as it was running a bit slow, WTF, no idle screw in the left carb, has fallen out while on the test ride, still running OK but will have to find another idle screw, turned the bike on and off about 10 times and it started first kick evey time with ease.

Ashley

jseng1 · Oct 1, 2011

I'll send you a new idle speed screw today.

john robert bould · Oct 1, 2011

pvisseriii said:
1up3down said:

Well, after spending 15 years with a single Mikuni and then over a year ago switching to the flat slides:

Starting: Same, one kick, at most two

Idle: Same, like a rock

Performance: Flat slides are much stronger flow, not only from 4500rpm as would expect, but also right off idle

Click to expand...

I am in agreement here. I will add that with cold starts, I only have to pull the left choke (the right is a bit of a bear to find).
Fuel line, I have a tee in the middle running line off right angle fittings to the center of the tank line, Then a 5/16 line straight down between the maniflods to another tee. From there I loop under and over the right carb to connect the left and under and over the left to connect to the right. I pulled a WOT to the ton mark with only one pedcock open.

I tried the short route with the gas lines and found that it is just too easy to kink and suffered starvation for it. The big loop may seem strange at first but works well.

It is said by Jim that the balance tube is not needed. I found the idle easilier attainable and steadier down to 500rpm. I keep it at 900rpm. It stays that way all the time.

Yes a tight kink, will cause starvation, seams OK when cold,but engine heat will soften the tube,,just to add insurance, wrap stout wire around the bend area.

New keihin flat slide carbs

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