[Sloppy]

Hi guys, we're trying to troubleshoot a problem on Greybeard's TW. It starting running rough and dying at stoplights when he was riding yesterday. We bought a new battery, checked and cleaned all the electrical connections, looked for air leaks, put in new fuel, and we're looking for other stuff to try...basically, the bike is a little hard to start, but we've got it idling well on the stand. Standing the bike up vertically will kill it instantly. Any ideas?

 

[dizzle2]

is the tank full? i had an issue like that and found out the fuel petcock is super long and the thing starts to die when the tank gets below half. check the fuel level, float height, air filter, and clogged jets. there are also filters on the end of the fuel petcock that may be clogged.

 

[Sloppy]

is the tank full? i had an issue like that and found out the fuel petcock is super long and the thing starts to die when the tank gets below half. check the fuel level, float height, air filter, and clogged jets. there are also filters on the end of the fuel petcock that may be clogged.

Thanks for the tips. We have the tank full, tried on both regular and reserve, checked the air filter and petcock filters. We'll dig into the carb and other stuff after lunch.

 

[dizzle2]

before that makesure there is flow by taking the fuel line off the carb and then turning on the fuel to see how much fuel is coming out. be sure to do it in a gas can so it doesnt get everywhere.haha.

 

[Sloppy]

before that makesure there is flow by taking the fuel line off the carb and then turning on the fuel to see how much fuel is coming out. be sure to do it in a gas can so it doesnt get everywhere.haha.

Yeah, fuel is flowing fine from the tank to the carb. We did find a little water in the float bowl. For some reason, after all the cleaning and connection-checking we did, the bike doesn't want to start at all. It kicks over and fires a few times, but won't actually idle anymore.

 

[dizzle2]

try 2 1/2 turns out on the fuel screw. make sure choke is pulled out. make darn sure there isnt a missing screw/open hole on the end of the carb connecting to the hose that goes to the engine. report back with your observations.

 

[Sloppy]

try 2 1/2 turns out on the fuel screw. make sure choke is pulled out. make darn sure there isnt a missing screw/open hole on the end of the carb connecting to the hose that goes to the engine. report back with your observations.

The side of the carb that connects to the engine is in good shape, snug, with all the screws in place. We definitely choked the bike. I'll ask my father where he has the fuel screw set to.



Also, in the bottom of the float bowl, we found the Main Jet cover (that little plastic circle with a hole in it) was rattling around free instead of being seated in the bottom of the float bowl like it appears it should. We're trying to figure out which side faces up, the concave or the convex. The shop manual picture is too small and blurry to tell.

 

[dizzle2]

i have no idea on that one. maybe qwerty could chime in...? i just had another idea. if it is idling fine then i would suspect the kill switch which i believe is connected to the kickstand might be an issue. not 100% on that one.

 

[qwerty]

I don't think Tdud still has that little plastic piece in the carb.

Try it one way, then the other. If the bike was running fine, then suddenly started acting up, something changed to cause the bad running. Something broke, slipped, or fell off.



Perhaps a loose wire connection? Stand it upright, kick it over, check for spark.



Perhaps a bad switch? Check the wiring diagram, then short or open one at a time, as appropriate.



Getting fuel? Check it held upright, not just on the stand.

 

[Sloppy]

Thanks for the help guys.



Problem solved! The bundle of wires running to the stator was improperly routed and rubbing to bare wire on the drive shaft, causing intermittent shorts. We found this out by doing continuity tests on the wires above and discovered wiggling them could cause resistance fluctations

 

[qwerty]

Well done!

 

[Sloppy]

Enjoying the fruits of our labor

 

[Dave Nafziger]

Enjoying the fruits of our labor

 

[Dave Nafziger]

So it runs, which means the part of the stator that feeds the ignition is performing,

but it isn't charging. The reason I think this is that I can't get a voltage surge by

revving it, and the battery is only good for a bit of cranking. Sloppy and I are in awe

and wonder at the stupidity of Yamaha to pull the kick start from newer models....how do

you guys do it? I hate to think of messing with the stator-- only a 1000 miles on it.

I am going to by- pass the kick- stand switch, since it has made trouble before,

and possibly monkey with the neutral switch, pull the battery lead to the positive and

look for resistance; also main switch is suspect. Any short-cuts from experience?

Greybeard

 

[Gerry]

Is it possible to get a picture of the 'bad point of connection'. The term "drive shaft" does not compute. More detail/pictures will certainly help others in the future. Thanks for the follow-up, perhaps more would be of benefit. Gerry