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can bike carbs be used as down draught carbs?!
blakep82 - 2/10/08 at 11:23 PM

just seen this off bogg bros


my carbs didn't quite end up at the intended angle when i finally got the on the engine. not too bad, but got me worried til i saw that picture.

mediabloke - 2/10/08 at 11:36 PM

Blimey! They do look almost (but not quite) vertical! I'd have thought it'd make for many hours of float-height adjustment fun...!

blakep82 - 2/10/08 at 11:41 PM

been looking at the price of carbs again, they've gone up a lot in the last year...
my zzr1100 carbs weren't the best when i got them (missing screws, or broken in the holes...) but were £35 now they're minimum £75 on ebay.

don't know whether to get another set (R1 with TPS maybe?) or try and get the bits to rebuild these ones.

robertst - 3/10/08 at 01:03 AM

i dont think u can unless you somehow change the float configuration so that the floats are level at that angle...

lsdweb - 3/10/08 at 06:24 AM

They look like throttle bodies to me!

02GF74 - 3/10/08 at 06:47 AM

they do look like carbs don't they?

Maybe they are in that position on the original bike?

Fitting them vertically will meanthe needle valve is horizontal (normally it is vertical) as well as the flaot being in the wrong position - not sure if they can be modified.

I guess you can always send an e-mail to BB?

coozer - 3/10/08 at 06:54 AM

I asked Dave about the engine in that picture when I was down there cause I was amazed as well. He assured me they where standard R1 carbs with no mods. Replacing a git big Holly they gave more power and more economy.

I asked about the float chambers and he said the main jet tube is totally immersed anyway so the angle doesn't matter.

Non believers? Ring Bogg Brothers and ask!

Steve

r1_pete - 3/10/08 at 07:16 AM

On the R1 the carbs are at about that angle, not fully vertical perhaps 15 degrees off.

lsdweb - 3/10/08 at 07:37 AM

quote:

He assured me they where standard R1 carbs with no mods


I thought I could see fuel rails!

I'll get my coat!

02GF74 - 3/10/08 at 07:52 AM

quote:
Originally posted by coozer

I asked about the float chambers and he said the main jet tube is totally immersed anyway so the angle doesn't matter.



I don't believe that - ofcourse the angle matters!! Unless there is no float/needle valve in the chamber.

Anyways, what I believe and whether I am right or wrong is neither here nor there.

r1_pete provides the explanation - like I hinted at in my previous post - they are mounted more or less vertically in the original fitting.

r1_pete - 3/10/08 at 08:30 AM

I know many people dissagre, but I still believe bike carbs should be used at as close to the ange they were mounted on the bike.

But, when a bike with the engine transversley mounted accelerates, fuel is 'sloshed' backwards in the carbs, so in effect the fuel level in there is at an angle to horizontal, keeping the main jet immersed.

When a longitudinally mounted car engine with bike carbs accelerates the fuel is effectively sloshed sideways in the carbs, which can un immerse the main jet, so fuel starvation can occur. This wont show on a rolling road as the car is stationary.

So in reality, where extreme angles are used in the bike, a lesser angle is preferable in a car with longitudinal engine.

02GF74 - 3/10/08 at 09:03 AM

^^^^ I hear wot you are saying r1 and agree about the orignal mounting.

not sure as to how much effect the sloshing has since the float is quite wide - if one side of the float sits in less fuel, the other sits in more so the nett effect should be about the same.

Landrovers with SUs and other carbs run quite happily at 45 degree inclines, declines and slopes.