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Bike Carb plumbing
Mole - 14/9/08 at 08:07 AM

I wonder if any of the bike carb experts can help me out with this one. Bike carbs have been fitted for a while now and I've reached the stage where by I want to start the engine. However the float bowls on the carbs won't fill so and I believe its because I've plumbed the carbs up incorrectly (CBR 600).
These carbs have four feeds for fuel the two inner ones are plumbed together and I have the two outer ones feeding into a t piece connected to the fuel pump. Is this wrong, and if so how should they be plumbed up.


indykid - 14/9/08 at 08:18 AM

sounds like you've done it wrong to me unless you've got a different set of cbr carbs to any i've seen before. fuel should enter into the two plastic T pieces on the lower side of the bellmouth side of the carbs. i believe the inlets are 10mm dia.
it then flows to the left and right halves.

the only way i can think you've done it is if you've plumbed onto the drains on the bottom covers, in which case, it's totally wrong as there will be a screw in the way and would negate the operation of the float.

do you have a picture?
tom


indykid - 14/9/08 at 08:21 AM

see this thread

the fuel inlet is the grey pipe at the bottom of the picture with the brown t piece in the middle of it. it runs up to 2 black plastic Ts in the carb bodies.

tom


Mole - 14/9/08 at 08:24 AM

I don't have a photo yet but I'll take one later. I'm pretty convinced I have done it wrong but I haven't plumbed onto the bottom of the carbs.
Thanks for the link, my carbs have four connectors on the "rail" where the one on the picture has two.


[Edited on 14/9/08 by Mole]


David Jenkins - 14/9/08 at 09:39 AM

Have a look on my website (www link below) and follow the menu to the bike carbs bit - one part details the components of CBR600 carbs and what they do (and how I modified them!).

This presumes that your CBR600 carbs are the same as mine - there are a few variants.


UncleFista - 14/9/08 at 10:01 AM

I have a PDF (17Mb) that's a copy of the Honda workshop manual. It's the chapters concerning fuel system, including exploded diagrams of CBR600 carbs.

Anyone who wants a copy, just ask


Mole - 14/9/08 at 01:31 PM

Here is a picture of how they are currently plumbed up. The fuel pump cuts off before the carbs fill. I've tried disconnecting the loop in the middle and attaching the fuel supply to each side but this just pushes fuel out of the other end. Rescued attachment bike carb plumbing.jpg
Rescued attachment bike carb plumbing.jpg


Mole - 14/9/08 at 01:59 PM

Okay, so they are not fuel inlet are they. Can anyone lend me a pointy hat with the letter D on the front?