TW200 Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I have a 2003 TW that refuses to start. It was running fine until it suddenly stopped at a stop light. We diagnosed it and found that it had no spark, but after replacing the magneto/stator yesterday we were able to get a visible spark. However, it still isn't starting. It has a new lithium battery we got a little over a month ago. Voltage tests show that its working fine, and we've tried bump starting and jump starting from another battery. We tried starter fluid, and still nothing. Air presses on my finger when holding over the spark plug hole and trying to start it, and it smells of fuel and trips from the carb after the petcock has been left open for a few minutes, so it seems that it has all three elements of spark, fuel, and compression. This bike has had a history of being difficult to start. We're going to go get a compression tester later this after to confirm that we have compression, but after that I'm not sure what to do. Any suggestions would be greatly appreciated!
 

·
Super Moderator
Joined
·
5,166 Posts
trips from the carb after the petcock has been left open for a few minutes !
Should drip from the carb in seconds - and if it takes a minute or two before dripping when not running with none of the bleed screws open, then you have a problem with the carb

That's your starting point - fuel supply

Either the petcock, or the carb itself .....
 

·
Registered
Joined
·
9 Posts
Discussion Starter #3
I thought carb issues might have been eliminated when it didn't fire up for a few seconds with with the starter fluid. Is that not the case? If so, do you think I need to do a full carb cleaning?

Thanks for your response.

Should drip from the carb in seconds - and if it takes a minute or two before dripping when not running with none of the bleed screws open, then you have a problem with the carb

That's your starting point - fuel supply

Either the petcock, or the carb itself .....
 

·
Registered
Joined
·
1,305 Posts
Could still be a weak ignition coil or weak plug. Could be air filter. Could be fuel quality or supply. Slight chance it's CDI but I think a failing CDI can still start up sometimes. It could be more serious like a messed up valvetrain, cam chain tensioner or very low compression, but those are much less likely to occur at a stoplight unless you were low on oil or had crazy high miles/weird noises and maybe no valve adjustment ever. Just unlikely any of the serious ones like that would happen without warning. What does the spark look like and where did you spray the starter fluid? A better test may be a teaspoon or so of fuel in the spark plug hole. If the fuel was running low it's very possible that something got sucked in and is obstructing fuel delivery. Occasionally folks only find out they were low on fuel when they pull the clutch in or come to a stop and the bike dies. Did it die as you stopped or while stopped?
 

·
Registered
Joined
·
1,077 Posts
A. How bright is the spark? Bright white/blue, not yellowish?
B. What is spark plug gap? Under compression, a wide gap may not fire.
C. How new is the spark plug?
D. What is color of spark plug?
E. Has any work been done on the timing chain?
F. What were voltage tests? (1) Key off? (2) Key just turned on? (3)While trying to start?
G. Choke/enrichener on or off?
H. What is setting of mixture screw? Is it open to about 2 1/2 turns from gentle seat?
I. Air filter removed to squirt ether? How much ether? One second blast while cranking?
 

·
Registered
Joined
·
8,371 Posts
Check all the safety switches. Kill switch, neutral switch, kick stand switch and also all the various ground wires behind the head light, most are black. Any of these switches that fail will cause the bike to not run even if you do see spark at the plug. They are all interconnected into the light box beside the speedometer.

GaryL
 

·
Registered
Joined
·
28 Posts
This might sound stupid (because it is) but I had pulled the plug on mine to check spark and simply failed to plug the wire in completely when I reinstalled the plug. The spark plug wire "clicked" once and seemed like it was seated but it was not. The spark checked OK when I tested it but obviously the bike wouldn't run when I tried to start it.

I just had to push harder to force a more solid click and it worked fine.
 

·
Registered
Joined
·
2,324 Posts
I have a 2003 TW that refuses to start. It was running fine until it suddenly stopped at a stop light. We diagnosed it and found that it had no spark, but after replacing the magneto/stator yesterday we were able to get a visible spark. However, it still isn't starting. It has a new lithium battery we got a little over a month ago. Voltage tests show that its working fine, and we've tried bump starting and jump starting from another battery. We tried starter fluid, and still nothing. Air presses on my finger when holding over the spark plug hole and trying to start it, and it smells of fuel and trips from the carb after the petcock has been left open for a few minutes, so it seems that it has all three elements of spark, fuel, and compression. This bike has had a history of being difficult to start. We're going to go get a compression tester later this after to confirm that we have compression, but after that I'm not sure what to do. Any suggestions would be greatly appreciated!
I had something similar happen on my 1993 before. 1st double check the kill switch. I have bumped them off at lights before. The odd thing I did which seemed to work was to push it lightly with the clutch engaged, not held in, and just lightly bump it a couple times. Then put it in neutral and try starting it. After I made it home I would tighten my cam chain adjuster. I always suspected that the cam chain was a little loose which may have had the timing off just a tad. All I know was I got it started after it died at the light doing that method. It happened a handful of times. If it has been consistently been getting harder to start your valves may be going bad so the compression test you mentioned is the way to go. Good luck.
 

·
Registered
Joined
·
305 Posts
Spark can sometimes be visible outside the engine, but it doesn't jump when under compression. Generally that's evident if the spark is dim/yellowish when outside the engine, it may fail to jump when inside. You want a bright, blueish spark.

If you can smell fuel and starter fluid isn't getting you anything, it's almost certainly spark. Bad CDI is a possibility, they can act up in various ways. Sometimes the spark is weak, sometimes they work fine cold but fail after running a while, sometimes they just up and die. Tough to know, and the diagnosis is generally "replace with known good" to rule it out.

If a kill switch or safety interlock is bad/stuck you will get no spark and the electric starter should not operate.

Unless compression is extremely low, the engine should at least pop over and run (power will steadily decline as compression fades, but it has to be virtually nil for the engine to not even fire). That's also not something that suddenly goes bad idling at a light. Can check it if you want (120-130psi is healthy). Make sure to hold throttle WOT on a warm engine while doing the test or you'll get a low result.

If you're dripping from the carb with the petcock open sounds like the needle/seat are sticking or bad. That can cause a rich condition, but I'd think it would still run to some extent.
 
1 - 11 of 11 Posts
Top