Kawasaki Vulcan Forum banner

carburetor flooding self inflicted maybe

9K views 15 replies 5 participants last post by  sfair 
#1 ·
I have a vulcan classic 1500 27,000 miles. Thought it would be a good idea to remove reed valves and evaporative stuff since I have put on vance and hines true duals. I have not done anything to carb and was planning on rejetting after this stuff was deleted. When I removed a couple of hoses I capped them off. Now with the carburetor flooding it makes me wonder if any of them needed to be open to atmosphere. Really hoping SFair can chime in quickly to give me some direction. was running fine no problem till decided to delete some stuff.
 
#3 ·
Hi,

I had a very similar issue with my 1998 Vulcan 1500 classic and it seems many others had related and/or connected issues. I'll tell you my story which I think is the weirdest of all but it might help you with the investigation of yours.

Intro: I got the motorcycle second 2015 and in 2016 the engine broke. When my mechanic opened it up, it seems some previous owner had it partially and badly rebuilt. So I ended up rebuilding it all, again (just my luck I guess). Once the engine was rebuilt, I performed by the book break-in and everything was OK. No carb flooding even if I already was using the Vance & Hines Longshots and K&N filter but no re-jetting (even if I have the kit :) ).

At 1600km since revuild (about 1000 miles) break-in was over and I made the final oil change. Then I drove another 2300 km (about 1500 miles) with NO issue.

Then out of the blue, the carb started flooding. Basically I rode the bike around the city, I parked it and then when I wanted to leave, I started it and it choke pretty quick while making a poodle of gas on the ground.

Note: Mind you that my carburetor is, I think, the most complicated Kawasaki installed on an 1500. Beside any normal carburetor does, this one have the electronic TPS (throttle positioning sensor), low emissions hose entry and valve and the coolant input so the carburetor is kept cold or hot together with the engine.

Then the fun begun:

1. I checked the carb float and pin assembly - it was ok but I ordered a new one anyway. My mechanic removed the carburetor, cleaned it all up thoroughly, checked jets, all diaphragms installed the float and needle. Problem was still there. Engine starts idle for a while then choke and stops. Then gas poors out of carb.

2. On forums people was telling me to check all the hoses to check if none is pinched or damaged so pressure is OK. I checked them all by removing them, then checking them individually and then putting them back. SAME issue was there.

3. Then from forums I found out I have to check the TPS sensor. In reality this sensor is just a variable resistor, nothing fancy but the price. I tested it using the procedure recommended in the Clymer after market manual, and I discovered that it was working ok for 1/2 the throttle but then it was showing a value like it was some short-circuit. I removed the TPS and then used high pressure air to clean it. I installed it back and tested it again and now it was ok. So it seems a bit of dirt, or a small piece of metal was there. Anyway, the TPS was ok. Then my mechanic installed back the carburetor. SAME problem.

4. Then, on other forums people recommended to check the fuel pump, becasue it is possible it pushes too much fuel. I measured the pump electrically like it is recommended in the Clymer manual. Apparently it might had a problem. I ordered a new fuel pump and instaled it. SAME problem. I put the old pump back, SAME problem. In the end I put the new pump again and continued with the investigation. SAME problem.

5. On other forums, people told me to check the vacuum valve, the one that is part of the gas re-circulation system (the one you disabled). I checked that valve and indeed it was malfunctioning so I ordered AND installed the brand new valve. SAME problem.

At this point, it was driving me, and my mechanic crazy. Then, since the carb was flooding even on idle I got an idea.

6. I bypassed the fuel pump: I disconnected teh fuel pump from electrical system and connected the hoses so the fuel was poring from tank, through the filter and directly to the carburetor. I've put the tank in a position a bit higher so gravity did the job. I started the engine and, at idle it was NOT flooding anymore. Everything was OK. Of course I could not do this on a test drive. So it seemed that the issue was fuel pump related, but I had the old pump and a brand new pump. It was impossible for both of them to be bad. So I reconnected the pump back and put everything together. SAME problem.

The problem was still there but, at least, I kind of isolated the root cause that is the fuel pump or the CDI system. My motorcycle has a CDI system and not an ECU. The ECU was added in later models. If you have an ECU version, there is a way to diagnose the electronic issue. The process is described in the Clymer manual.

7. Then my mechanic found some shady recommendation done by a Vulcan Main Streak owner that was telling us that, for these old models, the CDI has a system to identify an issue and enters in an 'error state'. But it does not have a system to reset an 'error state' like you have in case of the ECU systems. The solution is to disconnect the battery for 30 minutes and then reconnect it back. I did this and the problem WAS FIXED.

Basically, the CDI detected that I had an issue with the TPS (that I later fixed cleaning it with pressurized air) and it entered in an 'error state' where it was setting the fuel pump to max output so you can still reach your destination. And it stayed in that 'error state' until I reset it.

It runs like a charm now.

You can try any of the above attempt, from the most easy to implement (disconnect battery for 30 minutes, then try to bypass the fuel pump, then check float and pin, hoses, etc.).

If you manage to fix it, please reply here so other people knows about it too.

Good Luck
/3ng
 
  • Like
Reactions: Braddah Ry
#5 ·
Hi,









The solution is to disconnect the battery for 30 minutes and then reconnect it back. I did this and the problem WAS FIXED.

Basically, the CDI detected that I had an issue with the TPS (that I later fixed cleaning it with pressurized air) and it entered in an 'error state' where it was setting the fuel pump to max output so you can still reach your destination. And it stayed in that 'error state' until I reset it.


/3ng
1. Ignitor has no "error" state and disconnecting battery does nothing to "reset".
2. Fuel pump pressure is fixed and is in no way controlled by ignitor.

Sorry, but the information has to be corrected.
 
#4 ·
Thanks for the reply. I did figure out it was self inflicted. When removing the evap system stuff and doing the reed valve delete I capped off 2 of the ports on the carburetor. Once I removed the 2 caps tonight it fixed itself. Hope I was able to entertain some of you. But now I have another question. Should I just leave those 2 ports open to atmosphere or put a hose on it with some type of filter? Surely someone out here has removed evap stuff.
 
#9 ·
Hey,

Please have a look at this PDF (page 2) http://www.dynojet.com/pdf/2167.pdf

These are the instructions on how to re-jet your carb. The last step of the process is the one that disables the gas recirculation system. As you can see, only one plug (that is supplied with the jet kit) is put inside one hose. This is a jet kit for Vulcan 1500 D&E models but if you go here: Jet Kit Products for KAWASAKI MOTORCYCLES you can see the complete list of jet kits and PDFs available. Pick the one that correspond to your 1500 model and year and you should see how to disable that.

Please let us know how it works.
 
#8 ·
Yes, all 4 spark plugs were looking dirty like in the first picture and the carb was getting flooded at idle. I could not even ride it at all.

After I did the 30 minutes battery thing, carb was not getting flooded anymore at idle and I did 2 rides. First wast the same day, about 10 miles and the next day, to double check things I did a 50 miles ride. I was not daring to do a longer trip as I was afraid it will start flooding again. Everything worked just fine.

Once I got back from the 50 miles ride, I let the engine cool until the next day. The next day I extracted the plugs and, more or less they were looking like the one in the second picture, clean and dry.
 
#10 ·
I have a 1999 Vulcan 1500, 29K miles. same thing happened to me, it has a stage 1 kit in it with K+N filter. I got a float and needle kit and had a hard time setting float level, could not get it set right, after a few days of frustration put the old set back in. It now runs like a champ. Any thoughts or did I screw up in reverse. by the way carb was cleaned twice, pristine re-build, plugs looked rich at first now new plugs are perfect. twilight zone material?????
 
#13 ·
Nope, my bike does not have the evaporator stuff.

It does have the reed valves, and the vacuum valve that have the 4 hoses connected to it:
  1. one thin hose connected to the carburettor (control pressure)
  2. two thick hoses connected to the front and rear reed valves (these takes part of exhaust gasses and are input to the vacuum valve)
  3. one think hose that goes to the air box (this is the output from the vacuum valve that put those exhaust gasses back into the air intake so they are properly burnt, you know, to lower emissions)

And yes, I had this valve replaced with a brand new one because the old one was not opening at the right pressure/it was kid of stuck.
 
#12 ·
if you guys have a 1500 carb bike and you are using the dynojet adjustable needle from the dynojet kit, that's your problem with the bike not running right, use the stock needle
 
#14 ·
the problem is still there :(

Hi sfair, you were right. The problem is still there.

A lot of flooding in the carburetor and it spills on the side too.

As I already mentions I already changed:
- fuel pump (OEM)
- float (OEM)
- even the freekin vacuum valve that controls the recirculated exhaust (OEM).

I have checked the TPS sensor exactly like it is recommended in the Clymer manual and it shows the proper values (used voltmeter and all).
I measured the pump using an ohm-meter and both, old pump and new pump shows the exact resistance value, about 10KO even if the Clymer book say it should be above 20KO. Again, it is a brand new OEM fuel pump.

The only modifications I did to the bike are:
- I exchanged the stock exhaust with Vance & Hines Longshots and I put HD baffles on them as the sound was too high
- I replaced the stock air filter with a K&N one.

As I said, last year I rode 4000km with no issue, using the above mentioned setup, then this problem appeared.

Could anyone please help me with this? The mechanic tried it all possible approaches as well, removed carb, cleaned it, adjusted, etc.

Thank you in advance for any suggestion.
 
#15 ·
3NG
Even though my problem was self inflicted it does sound similar to what you are experiencing. My problem was I plugged one of the ports on the carburetor and it should have been vented to atmosphere. Maybe it is possible one of your hoses has collapsed or is kinked. It was the large diameter hose looking at the carburetor on the top left side. You can try pulling it off the carburetor and see if it still floods.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top