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Bike Carb Trumpet Angle
locosaki - 30/9/10 at 07:21 PM

I've got bike carbs fitted to my engine on a bogg manifold, Now when I fit my trumpets on they stick through the bonnet due to the angle of the carbs on the manifold.

The trumpets just push into a bit of rubber on the original airbox so if I fully push the trumpet in at the bottom and half slip it at the top into the rubber connector I then get the trumpets sitting level and under my bonnet (which I want)

Now I'm wondering due to the change in angle will this affect air flow into the carbs ?

jacko - 30/9/10 at 07:31 PM

If the trumpets are that close to the bonnet how are you going to fit a air filter ?
what carbs are they ?

SPYDER - 30/9/10 at 07:59 PM

Like Jacko says, if you have no air filter it's not the air flowing into the carbs that you need to be concerned with!
It's everything else flowing in!

locosaki - 30/9/10 at 08:00 PM

There ZX9r carbs, If I stick a filter on with the trumpets angled it clears the bonnet just I'm just unsure if tilting the trumpets down a little would cause problems ?

r1_pete - 30/9/10 at 08:01 PM

Agree with Jacko,

You should have 1.5 x the choke diameter between the end of the trumpet and any 'obstruction' e.g. airbox lid, filter plate etc.

jacko - 30/9/10 at 08:12 PM

quote:
Originally posted by locosaki
There ZX9r carbs, If I stick a filter on with the trumpets angled it clears the bonnet just I'm just unsure if tilting the trumpets down a little would cause problems ?

Don't forget you want cold air into the filter hove a look in my photo archives the section zx9r carbs / manifold it may give you some ideas
Jacko

locosaki - 30/9/10 at 08:18 PM

I have the correct distance from filter to trumpet and with the trumpets angled down that puts them right at the back of the grill directly into the airflow.

jacko - 30/9/10 at 08:43 PM

It sounds like that will be ok do you have any photos of the engine / engine bay ?
Jacko

locosaki - 30/9/10 at 08:50 PM

I don't at the minute but could certainly take a few tomorrow to give you an idea.

I was just concerned that the angle of the trumpet going to the carb would disrupt the airflow maybe cause turbulance in saying that the fuel supply should still be spot on as the carbs mate to the manifold perfectly so really shouldn't get fuel drop out !

Angel Acevedo - 1/10/10 at 01:02 PM

Is cutting a couple of mm possible,
Diference in performance may not be noticeable at all,
But reading Carroll Smith Tune to win,
Every difference counts, so you may be looking for another solution, maybe a small scoop will give you colder air and a little bit of ram air pressure.
HTH

JF - 2/10/10 at 11:08 AM

Don't worry about ram air... it more an advertising tool then anything else.

It just adds a few hp at top speed, if done well...