07 JCL 250A Carb Problem By tapntx (Read 7,481 times)

[Alleyoop]

Man sure sounds like something when hot is expanding and then making contact. I would now start it up and start hitting wires and CDI, Coil, wires etc and see if something that you move makes it die.
Alleyoop

[tapntx]

Mar 2, 2011 18:15:55 GMT -6 @zugzug said:

Sounds like the fuel pump to me.

Checked the Fuel pump right after the fan came on, nothing different than when I went out this morning and tried it and timed it filling up 16 oz cup.

alleyoop,

I cant see any changes with a Voltmeter connected to the battery. The spark is just as hot when cold as it is when the fan comes on. When I had the bike apart this am for the valves, I did not see any chaffing or any thing unusual with wiring. I had the front end off last week, and again no splicing or anything unusual.

The strange thing even when the bike is cold, and I pull out of my driveway WOT, it never misses a beat, no miss or hesitation. I only notice when stopping or turning left the bike will die. I could not find any indication of a Tip-over sensor anywhere on the bike.

And when the bike is at full operating temp, it does not matter where the clip is on the needle or where the Air/ Fuel screw is, it will not die and starts easily.

Thanks again for all the help, I do really appreciate it.

Todd

[Alleyoop]

Ok, just another thought since you mention it has trouble when stopping or turning left.
Check your cables maybe something is interfering and or pulling on something when you pull the brakes and or turn.

Checking with the Volt meter is not going to help if something is moving on you only in certain conditions. I am talking about aatually start moving the wires with your hands and CDI, COIL, REGULATOR etc.. to see if when something moves it dies.
Alleyoop

[tapntx]

Mar 2, 2011 21:13:03 GMT -6 Alleyoop said:

Ok, just another thought since you mention it has trouble when stopping or turning left.
Check your cables maybe something is interfering and or pulling on something when you pull the brakes and or turn.

Checking with the Volt meter is not going to help if something is moving on you only in certain conditions. I am talking about aatually start moving the wires with your hands and CDI, COIL, REGULATOR etc.. to see if when something moves it dies.
Alleyoop

I will go through it again tomorrow, but I actually traced all the wires to make sure nothing was pinched or damaged in anyway. The real kicker is it only has the Left and stopping problem till it warms up. And even before that if it was missing a pulse from the CDi I would feel it miss. It never does, from Cold pulling out of drive at WOT it never misses a beat . And as long as I have 1/4 or above throttle it wont die. I dont think it is a CDI issue, and when I say I can jar it and make it quit, I mean a very subtle movement.
I will try and take a video of it tomorrow to show you how gently I can touch it and make it quit before it gets to operating temp. All while idling fine. It is not like it is an electrical issue or even pump issue. It just starts to hesitate, not like it misses or just quits, it is like it gets a huge gulp of fuel when it gets bumped.

jrryan,

Oh I wont give up. I love the challenge.

You might be on to something with the Leaking Diaphragm. I have read about this but mine seems to be fine. I checked it a few times, and also actuated the slide in the carb. Acted like the one in my DR650. but it could be a small leak. I cant ssem to get any color in that plug other than at idle.

Also my Carb Slide has the White plastic needle holder that you turn a 1/4 turn to lock in place. I always make sure it is working right before placing back in the carb.

80-85 mph, wow that would be nice. Mine strains to get to 60 and I am below 1000 and weigh about 200# I figured I should be getting better performance, but I know there is a problem since that plug stays like new (White)

Not sure I need the ice, it is the opposite, it dies before warming up (Full operating temp). Once warm I cant make it die by shaking it or leaning it in any direction. I will check the CDi wiring, it looked clean when I re-mounted the CDI under the seat.

Thanks again guys, I will be sure to document my findings when I resolve this issue.

Todd

[zugzug]

The reason I said it might be the fuel pump is because it runs good when warm but once it cools or sits its hard starting until it runs for a bit again. Sometimes the pump or a leak in the hose will allow the fuel to leak down back towards the tank and it makes it hard to start until its pumping fuel again.

I tried to find ya a pic of the tipover valve but kinda tired. I bet rich has a pic of one. Its not very big. Its about the size of a 2 liter bottlecap with a nipple on each side. Usually mounted on one of the upper frame crossmembers. If its turned or swisted on ya (which is easily possible since many are just zipped tied into place) it could be causing those problems.

[Cruiser]

Well Todd, it sounds like you have a good mechanical and electrical knowledge of how your scoot should run. I'm wondering if there is more than one thing wrong.

A leaking diaphragm would not cause the hard starting and stalling problem. It would show problems above about 1/4 throttle which could explain the lean condition.

You apparently have an aftermarket electric fuel pump. Intermittent fuel delivery from the pump would not cause an immediate reaction by the engine. The float bowl has enough gas in it to run the engine for about a minute without any fuel input. You already did the vacuum leak check with carb cleaner with good results.

Your idle doesn't seem 100% even when fully warmed up. You said that it will stall under hard braking? It almost sounds like a lean condition through the entire operating range. Still sounds like a possible vacuum leak.

We will be waiting for any more clues. Good luck!

[tapntx]

BTW, since I had the plastic off yesterday I removed the Smog stuff and capped the Exhaust tube going to it. The problems I have listed were all there prior to this. I was hoping by removing some extra vacuum lines I might find the one that was causing the problem.

So now I have going to the Carb:

Fuel Line
Vacuum line from Manifold
Throttle Cable
Connector for Enricher
Bowl Drain

And the only line not connected to anything is the Fuel Tank Vent line.


Cruiser,

I agree 100% with what you are saying. If the pump was intermittent the bowl should have enough fuel for atleast a minute of run time. I know on my DR650 the bike will idle for over 3 minutes after shutting off the fuel.

On my bike it idles fine as long as it is completely up to operating temp. Today I will use my temp gun and see if I can pin point a certain temp that it changes.

Thanks again for all the help!!!

Todd

[tapntx]

Just to recap what has been done:

Cleaned carb thoroughly 3 times. Removing anything that can be unscrewed and blowing Carb cleaner through every orifice.
Upped the Main from a 115 to 130
removed all smog stuff (Same problems before this)
sprayed Carb cleaner all around carb while running, no change in RPM
Tried Diff Plugs DPR8EA and DPR7EA
Checked Valves both in Spec .004 In .006 Ex
Adjusted Float Level from 17mm to 22mm no change at all
Tried the air/fuel screw from Closed out to 3 turns. No difference
Needle clip positions 1-3 it has total 3 positions.
inspected the Diaphram, no tears, or cracks
Fresh Fuel added a little Sea Foam
Cleaned and re-oiled the UNI Air Filter
Checked all connections to Coil and CDI
Freshly charged new battery
Checked the float valve to make sure it closes
Bike has 4200 miles on it.



The problems are:

until it is up to full temp, (Fan comes on) it will die if it is leaned to the left or is jarred the slightest.

Also cant seem to get any color on the plug, it is bright white.

With the bike cold it runs fine when moving or under acceleration. It will die when stopping or idling or making a slow left. I can keep it running if I keep a little throttle while braking or turning.

Once the fan comes on, the bike will not die, even if I shake it or lean it to the left.

i think I will do a compression test today and just see what it is showing. I am wondering if I may have a leaky valve.


Todd

[tapntx]

Well I checked the Compression and it was around 150 PSI that is cold without adding anything to the cylinder.

I resealed the Manifold connection with Ultra Black RTV and replaced the O-Rings on the Choke Module.

I also went back to the 115 Main jet and sprayed a 1/2 can of carb cleaner all around and nothing.

The really strange thing this morning I cranked it up and it was running like a top. And as usual a little shake made it die, then after about 3 minutes it was running where it would not die by shaking it. The fan had not been on and the bike was barely warm.

I checked all the connections to the CDI module everything was clean and the connections seem tight.

So in my previous statements claiming that when it gets hot it will work correctly, I think is wrong. I think it was totally coincidental. One time today I let the fan come on and shook it and it died.

Here is a video I took with it dying, first thing this morning. The second video is just a few minutes later and not dying. I did not touch anything I just let it idle for a few minutes.

The bike cranked right up this morning and settled into a nice idle.



Thanks again for all the help

[tapntx]

BTW, I needed a break away from the Scooter and took a ride on my FZ6 today ;D


Todd

[tapntx]

Ok, finally I think I have good data and can say that the bike is running fine now.

Here is what I found, the Automatic choke was working intermittently.
I had cranked the bike and let it idle from about 70 degrees. I heard it stay in high idle and never went down. I heard the fan come on and went to shake the bike and it died. I opened the seat and felt the Choke module it was not warm at all. The connector was not making good contact, as well as the wires coming from it felt broken at the module. I spliced the wires, and tightened the connector. All seems fine now.

In doing this I had a thought of a way to make the choke sure fire. What if you wrapped a coil of coolant line around it. That way when the coolant was up to temp it would always keep it extended. It might take a bit longer than the electrical version but should still work in a pinch out on the road.

Another thought, if anyone has a similar scooter, try this. Go out crank it up cold, and just give it a tiny shake and see if it dies. I am assuming the temps need to be some where between 50 and 70. If it is real cold or real hot it will probably work correctly.

I was beginning to doubt myself about this bike. The problem is this is only the second time to work on a carb with electric choke. The other was a 2001 Honda Elite 80, with a severely gummed up carb. But I cleaned it really good and it worked flawlessly.


Thanks for all the help!!!
Todd

[Cruiser]

Good job curing the shaky idle! You said the scoot runs fine? Are you going to pursue the white plug (lean condition) problem? You should be able to pull 70 mph with no problem. Struggling to get to 60 mph sounds like there is a problem which could eventually burn a valve.

[tapntx]

jrryan,

I decided to reduce the Air filter size. I cant see a really good way to mod the muffler and keep it quiet.

BTW, thanks for giving me the jet sizes, for some reason I could not find that data anywhere.

Thanks again for the help and ideas!!!!

Cruiser,

Yes I am going to play around with that and see what I can come
up with. I may also reduce the Pilot jet to avoid too much fuel on warmer days .

Thanks again guys for all the help and knowledge.

Todd

[Alleyoop]

FINALLY the culprit has been found, GOOD JOB.
Alleyoop

[tapntx]

Mar 5, 2011 12:33:35 GMT -6 Alleyoop said:

FINALLY the culprit has been found, GOOD JOB.
Alleyoop

Finally, thank you again. That auto choke had me puzzled. Yesterday I rode the bike and everything was perfect. I parked it and let it cool for a few minutes. I cranked it back up, and let it idle for a few minutes. I noticed the idle never changed, I heard the fan come on and figured it was good to go. When I took the bike off the center stand it died. I immediately opened the seat and felt the Choke module it was not warm. I knew for sure that was the issue.

This morning it was some what colder here in Dallas. So I went out and cranked the bike. It cranked up perfectly and settled in a high idle just like it should. I shook the bike and it did not die. Because it was colder it needs more fuel. I just wish there was a way to adjust that Choke where you could tune it to your climate. If I lived in Alaska it would probably work flawless. But here in Dallas, I can see where you will need to let it warm up or let the choke close all the way before trying to ride it. Otherwise it is going to be getting too much fuel until that choke closes all the way.

Thanks again for all the help
Todd