Author Topic: Clean Pilot jets and it still wont run without choke!!!(Fixed) (Read 1895 times)

ericmu17 · « **on:** August 06, 2012, 01:07:45 PM »

Hey all. My 73 CB500 has had the carbs pulled 10+ times in the last couple weeks to clean the jets and jet some carb cleaner down the pilot jet hole. After all this I still cant keep it going without the choke. I cleaned the jets with compressed air birkabile carb cleaner carb jet cleaning tools and alot of patience. I can kind of keep it running without choke with half throttle but the exhaust starts smoking and it struggles badly.

Cb500 choke

ericmu17 · « **Reply #1 on:** August 06, 2012, 01:08:33 PM »

And the breather hose coming from the engine is smoking. Im at a loss.

harisuluv · « **Reply #2 on:** August 06, 2012, 01:15:33 PM »

Wow, ok there is a lot going on there in that video. Did you really take the carbs on and off 10+ times? Each time did you only address the idle jet? You didn't clean the rest of the rack at all, take it apart, address the fuel circuits, anything? Exactly what did you do when you "cleaned" them? Also, are you sure that smoke is coming from the breather hose? Cause it looks like it is coming from the airbox, like the valves are off and it's shooting back through the carbs. Can you comfirm smoke actually coming out the end of the breather hose?

Sniper X · « **Reply #3 on:** August 06, 2012, 01:18:10 PM »

I will add that bikes jetted way to lean need the choke on to run....but I need to watch the video from what hairsu said! I had this same problem when a guy way overfilled the crankcase with oil too...check the oil level!

Sniper X · « **Reply #4 on:** August 06, 2012, 01:18:42 PM »

Oh, and it also might be sucking air somewhere from the boots or manifolds.

ericmu17 · « **Reply #5 on:** August 06, 2012, 01:44:00 PM »

Yea I cleaned every orifice with carb cleaner. The manifold boots are new and I tightened them very securely. I made sure that carb cleaner ran out of the other side of every hole i sprayed it into. My next move is to just take it down to my mechanic and have his soak it in a ultrasonic bath.... It has to be the carb..... what the hell can be blocked though?

?

xnewmanx · « **Reply #6 on:** August 06, 2012, 01:50:54 PM »

At the end of the video you realize you're turning the choke ON... right???

That much smoke coming out of the breather (which should be routed from the port on the head back to the airbox) probably means that the rings are totally smoked or there is a hole in a piston.

harisuluv · « **Reply #7 on:** August 06, 2012, 02:15:05 PM »

Quote from: xnewmanx on August 06, 2012, 01:50:54 PM

At the end of the video you realize you're turning the choke ON... right???

That much smoke coming out of the breather (which should be routed from the port on the head back to the airbox) probably means that the rings are totally smoked or there is a hole in a piston.

Nice catch!

Fritz · « **Reply #8 on:** August 06, 2012, 02:46:39 PM »

Quote from: xnewmanx on August 06, 2012, 01:50:54 PM

At the end of the video you realize you're turning the choke ON... right???

Until the end of the video I thought "Besides the amount of smoke leaving the breather tube, it looks and sounds quite fine. Than I shrugged, when I saw the engined being chocked

Eric, I'm afraid that other problems that you encounter while getting your bike roadworthy are not that easy to solve

lucky · « **Reply #9 on:** August 06, 2012, 03:51:39 PM »

You do not have stock exhausts.
i cannot tell if you have a stock air cleaner.

Would like to know what the jetting ( main jet and idle jet) is, and what
groove( counting from the top) the slide needle clip is on.

Did you check the float height?

ericmu17 · « **Reply #10 on:** August 06, 2012, 05:24:40 PM »

Good lord.... Really?!?!?!!? So it's fine?!?!? I thought I was turning the choke off.... Wow...

ericmu17 · « **Reply #11 on:** August 06, 2012, 05:26:38 PM »

Jetting is stock. Idle 40 and whatever the stock main jet is.

ericmu17 · « **Reply #12 on:** August 06, 2012, 05:31:29 PM »

The breather tube smoke had no smell.... Could it be steam or something?

ericmu17 · « **Reply #13 on:** August 06, 2012, 06:13:59 PM »

This is also the 4th time I've fired her up since I bought her. The owner said it had been sitting for 4+ years.

lucky · « **Reply #14 on:** August 06, 2012, 06:16:32 PM »

Never use the choke to kill the engine. It is not a lawn mower!! LOl...lol

ericmu17 · « **Reply #15 on:** August 06, 2012, 06:54:26 PM »

LOL Ill keep that in mind Lucky.

TwoTired · « **Reply #16 on:** August 06, 2012, 07:00:02 PM »

Quote from: ericmu17 on August 06, 2012, 05:31:29 PM

The breather tube smoke had no smell.... Could it be steam or something?

Almost certainly water vapor, from the internal condensation boiling off. Get the engine to operating temp and then run for 15-20 minutes to get it all.

It'll make more condensation every cool down cycle.

ericmu17 · « **Reply #17 on:** August 06, 2012, 07:03:46 PM »

I did run it at operating temp for a while and it disappeared!.... I knew it had to be something burning off since it didnt smoke when I fist started her up.

Fritz · « **Reply #18 on:** August 07, 2012, 06:54:10 AM »

Also, letting it run just for a couple of minutes will produce water that accumulates since the engine is not hot enough for it to evaporate.

One source of this water is octane in the gas:
2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O

Another is just humidity in the air: Hot air stores more water and when the engine cools down, it condensates.

News:

Author Topic: Clean Pilot jets and it still wont run without choke!!!(Fixed) (Read 1895 times)