Author Topic: blocked carb? (Read 4838 times)

El Dopa · « **on:** February 19, 2007, 03:02:50 AM »

Hi all,

El Bandito has started running on 3 cylinders.

The forth cylinder dropped out at the end (fortunately) of a 200K cobweb-clearing thrash, about 5k from home.

The first thing I noticed was the idle dropping to nothing as I cruised up to a set of lights.

I got home, and I've done some basic checks.

There is strong spark on the plug for that cylinder, and it doesn't look fouled at all. I've drained some fuel through the carb nipple and it doesn't seem blocked, or watery.

The plugs and battery are practically new.

As it started playing up suddenly, I'm inclined to think it ISN'T water in the fuel. The engine was hot, it was a warm day, and it had been fine for 200-odd K up to that point. All the other three cylinders are running fine.

So.....I'm thinking maybe some gunk in the carb? Does that sound like the most likely problem?

r_outsider · « **Reply #1 on:** February 19, 2007, 04:02:12 AM »

Yes. Or something else with that carb, anyway. PITA, I hate those things.

PitterB4 · « **Reply #2 on:** February 19, 2007, 09:10:55 AM »

Is it only at idle/low revs? If so, it's probably a blocked pilot jet.

interfuse · « **Reply #3 on:** February 19, 2007, 09:32:10 AM »

What Rob said. Lots of posts on here about that.

greatmoorred · « **Reply #4 on:** February 19, 2007, 03:23:57 PM »

I know it seems a bit simplistic, but how low is your fuel ?
My B4 runs like a dog when its really low on juice.
Fill her up and shes good as new

Might as well start with the simple fixes.

El Dopa · « **Reply #5 on:** February 19, 2007, 03:44:11 PM »

Quote from: "greatmoorred"

I know it seems a bit simplistic, but how low is your fuel ?
My B4 runs like a dog when its really low on juice.
Fill her up and shes good as new
Might as well start with the simple fixes.

I did wonder about that. I filled up before I went out, and 200+K is getting towards an empty tank. I wasn't exactly cruising at low revs, either.

Thanks, I'll try that first.

gsxr400 racer · « **Reply #6 on:** February 19, 2007, 10:06:07 PM »

lol sound real familar ive been through to much with this bike hard to remember everything but that may explain why i bought a pingle fuel valve and raised the front of my tank here and i thought i raised the front to get more air to my carbs lol

pmackie · « **Reply #7 on:** February 19, 2007, 10:46:40 PM »

We had a rule at the shop I worked at, that you ALWAYS put some fuel in the tank before doing any work, even a tank that looked full.

Even with that knowledge, I can't tell you how many times I tore into something not running right just to find out it was low on fuel.

However, it is likely you have something in one of the carb jets.

gsxr400 racer · « **Reply #8 on:** February 20, 2007, 05:15:38 PM »

Quote from: "pmackie"

Even with that knowledge, I can't tell you how many times I tore into something not running right just to find out it was low on fuel.

thats a $99.95 dumb shit fee

El Dopa · « **Reply #9 on:** February 21, 2007, 04:08:48 PM »

Isn't the fuel. Half-filled the tank last night with high-octane go juice, and still only got three cylinders of inline goodness.

Next step - the carbs.

gsxr400 racer · « **Reply #10 on:** February 21, 2007, 08:43:17 PM »

then a fuel filter lol

El Dopa · « **Reply #11 on:** February 22, 2007, 03:17:00 PM »

There's already a filter in place.

Do they need cleaning or replacing regularly?

gsxr400 racer · « **Reply #12 on:** February 22, 2007, 03:27:56 PM »

I use a cleanable one but yes they do need replaced depending on the sediment in your tank they ususaly change colors to a dark pee color LOL but if to dirty they can cause fuel delivery problem!

Here is another tip for you all if you turn your carbs upside down and those rubber plugs fall out you need new ones

Fuel screw oring are important to seal or you have air leakage

the emulsion tubes if worn are important

checking the brass thin tube on the out side of the carbs for breaks is important

float level and sealing important

Ever have gas on top of your slides from turning your carbs over and not draining the fuel or removing your slides this can cause havac

Trying to remember the list as you tare apart your CV carbs is a process

If your floats fall out when you turn the carbs over guess what you need new orings they should be resistance to the point of having to lube up the orings to get the floats installed properly

Hope this helps someone

gsxr400 racer · « **Reply #13 on:** February 22, 2007, 03:32:03 PM »

here is another note as a coil breaks down it will usually only have enough juice to fire one plug this is under a load so if you take them out you will see them both sparking but when you put them in they load up

These bike do not like a dead battery either plays havoc with the electrical and makes you think you have more problems than what you usually have wich is just a dead battery!