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Will my bike carb manifold work?
whitestu - 15/1/08 at 08:21 PM

I finally got my manifold from Fatboy Dave today [thanks to Skidmark for picking it up for me].

I was expecting a manifold with the intakes at an angle so the float level on my ZX6R carbs would be as they are on the bike.

The intakes are actually at 90 degrees [as you would expect for TBs].

Does anyone have experience of using ZXR carbs [or any others] on horizontal intakes and if so did they work?

Cheers

Stu


r1_pete - 15/1/08 at 08:30 PM

From my experience with bikes, last one was a GSXR1100 with ZZR1100 carbs fitted (CVK carbs very similar to 6R) They had to be mounted so the float bowl face was horizontal, choke tubes about 45 degrees, they would not work when the choke tubes were horizontal. In general bike carbs need to be mounted in the same orientation as the bike, my bogg / ZRX750 CVK / Zetec manifold puts the carbs at an angle with the float bowl horizontal, I specified that but Boggs said it was standard for them.
Sorry its not what you wanted to hear, but horizontal chokes mean the floats dont work properly and you'll never get a proper mixture. Try to find a set of carbs from a suzuki GSXR1100 slingshot, they are horizontal choke, and would work with your manifold.
Rgds.
Pete.

[Edited on 15/1/08 by r1_pete]


Fatboy Dave - 15/1/08 at 08:50 PM

Better tell the self same ZX6R carbs on my 1.8 powered mk2 to stop working fine then...

You're not the first to have a manifold, and no one has yet said it doesn't work in three years of me making them.


short track 123 - 15/1/08 at 08:54 PM

Do you have any photos of the setup??


jacko - 15/1/08 at 09:01 PM

Bogg Brothers fitted r1 carbs on a rv8 look at there web you wi;ll see what i mean
Jacko

Sorry miss read your post forget what i said
your carbs will be ok just fit and enjoy the fun

[Edited on 15/1/08 by jacko]


whitestu - 15/1/08 at 09:11 PM

Thanks Guys.

Better get it fitted then.

Cheers

Stu


coozer - 15/1/08 at 10:24 PM

The carbs need to be at anangle so the split line of the float bowls are horizontal.

Heres mine on my zetec engine:


whitestu - 16/1/08 at 08:59 AM

Thanks what I expected, but it looks as though others have made them work wth a non angles manifold so I'll give it a go.

Cheers

Stu


DarrenW - 16/1/08 at 09:46 AM

So are you saying instead of the runners being horizontal to head face or slightly upwards they are fully vertical? My only concern is the total height with filters fitted and how much will be out of the bonnet? Do you have any pics?

I had a convo with Boggs about the float angle and the split line does not have to be horizontal. There is an element of allowance for the angle. The V8 install apparently worked very well. i think the common misconception is that people interpret the ideal angle as the only angle that will work. Simply not true. What happens in a transverse engine install when you go up or down a steep hill? or longitudinal when you go around a banked circuit??


02GF74 - 16/1/08 at 10:05 AM

wot dw says; ideally yopu want the float chamber to be hoirizontal but there is a range of angles that the carbs will still work.

now with the Bog bros v8, they may still be within these limit but if that engine goes on a camber e.g. taken off road or on a banked tracked, then the angle of the chamber may be out of limit so one would expect some deterioration in performance - either too much or too little fuel.


David Jenkins - 16/1/08 at 10:34 AM

If you look in the bike manual for my CBR600 carbs you'll see that they're mounted about 10 degrees off vertical. I have seen these used horizontal, presumably with success, but I chose to put mine at 30 degrees, which is the line of the float chamber covers.

Each to their own, I think.

There is one other factor, however - on my carbs there is a vent for the top of the float chamber that was part of when they were used with a cat converter (if the engine stopped, the vent was connected to the venturi, which meant that petrol flow stopped). We don't need to worry about using this system so we can ignore all its associated gubbins. In extreme angles, fuel could leak into the venturi unexpectedly. Not saying that this could happen with the carbs horizontal, but it does pay to be aware of where that vent is, and where it goes.


DarrenW - 16/1/08 at 10:44 AM

On my keihins its not actually the float split line that should ideally be vertically - there is another marker cast into the body at about 10degs that should be level (in an ideal world).


whitestu - 22/1/08 at 04:43 PM

Well, I guess I'll find out when I drive it!

Stu