Hi guys il give you an intro into my Civic. Heres how i bought it:




After plenty of welding and painting:

















Anyway the rad and everything is on now all fluids are in there but im having a problem with the bike carbs.

I currently cant get the engine to turn over but that could just be a weak battery.

The main problem is that the bike carbs are leaking fuel underneath. Im not familiar with carbs so this has been a big learning curve.

Im using a bike fuel pump from a CBR600 and the carbs are CBR600 F2 carbs. The leak is coming from the spouts underneath the carbs.

The most likely cause is the float valves are dirty and not seating properly. Take them apart and give them a good clean.

If the carbs are at a different angle to how they were on the bike you may need to alter the float height as well.
Stu

I did have them all cleaned before they where fitted but that was a while back.

I believe on the bike they are nearly virtical, I couldn't get them to anywhere near that angle.

I run my CBR600 carbs about 10 degrees above horizontal - don't worry if you can't manage to get them vertical!

I second the idea that the float valves might be dirty. Also, check that the choke mechanism is fully off (it's usually spring loaded to off) - this basically drips fuel into the intakes when set to on and, as such, is quite a crude mechanism. It doesn't work the same way as a normal car choke that limits the air going in - it adds fuel instead.

Ok cheers i will look into the choke, I may just strip them down and fully clean them again.

Could the 'spouts' be the float drains?

It is the drains the plugs where loose. My error!

Anyways now they leak from other places so im thinking maybe these carbs are not to be used with a bike fuel pump.

quote:

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Originally posted by kel eg


Anyways now they leak from other places so im thinking maybe these carbs are not to be used with a bike fuel pump.

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I am using a bike fuel pump. Im wondering if the bike initially had no pump at all.

^^^^ what he said!

Bike pumps give a large volume at low pressure, which is perfect. It's what I use for my CBR600 carbs, and it was a vast improvement over the general-purpose car pump I had previously.

Just a random thought - you haven't got a pump meant for use with an injected bike engine, have you?

Have these carbs been sitting around for a long time before you fitted them? There are a load of little o-rings between each carb body, used as seals in the fuel supply. For example, each pair of carbs is fed by a T-piece with an o-ring at each end - see below, on the left - if they have perished then you'd certainly get a leak.




[Edited on 6/4/15 by David Jenkins]

I was told the pump is off a 1995 CBR600 which is a carbed bike so it should be the correct pump. I may fit a regulator just to see what pressure its supplying.

Should be fine - you won't need a regulator with that.

NB: see my edit to the last post.

I will try to figure out exactly where they are leaking, but yes they could have been sat around for a while before i bought them.

I will try to identify the leak and then strip them back down check the condition of the O rings.

Thanks for your help so far guys.

It should be fairly easy to test those o-rings: turn on the ignition so the pump is running, then waggle/rotate each of those fuel inlet t-pieces as far as they go. If they're in good condition then they won't leak, but if they're perished then maybe you'll see fuel leaking.

If they are leaking, look at my website to see how to split the carbs (look in the menu for bike carbs). It's an easy job, but a bit time-consuming (and you need to pay attention to detail).

[Edited on 6/4/15 by David Jenkins]

You are feeding fuel into the correct pipes?

On my cbr900 carbs there were overflow pipes, pretty obvious fuel delivery pipes and a third set that went to an air breather into the air filter that looked like a fuel pipe.

Just a thought.

I've never seen the fuel connector 'O' rings leak even on old bikes.

Worth a look though, if someone is struggling to find leaks - and it's a simple check.

I still reckon it's dirt in the float valves.

Try making up a small bottle of fuel and a pipe to the carbs
See if they leak with gravity pressure only

I ran my bike carbs using a bike fuel pump on a T-piece setup. The pump runs constantly, pumping fuel in a loop from the tank to the engine bay and back to the tank. There is a T-piece in this loop to the carbs. This way they just draw the fuel they require. Not sure if that would help here?

quote:

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I ran my bike carbs using a bike fuel pump on a T-piece setup. The pump runs constantly, pumping fuel in a loop from the tank to the engine bay and back to the tank. There is a T-piece in this loop to the carbs. This way they just draw the fuel they require. Not sure if that would help here?

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