Hola-
First post here, and just want to let everyone know that if you are ever are in Central mexico and need some help or have questions, please contact me, I've been living here 4 years and riding 2.

Ok now to see if anyone can give me suggestions.

After putting 10000km on my 00 XT (20,000km total) without any problems, it suddenly started doing weird shit that no one can seem to figure out.
The bike runs like a champ for the first 30 minutes and then starts to lose power like it is not getting fuel. I give it throttle, but it sputters, doesnt respond and the rpms start dropping. As i give it clutch to down shift, the bike shuts off. It will start up again with the choke on, and ride nice for a couple minutes but then acts up again.
3 different mechanics have been through it, taking apart the carb, cleaning the tank, fuel filter, lines, jets, pitcock and everything else associated with fuel. I thought it was just mechanics doing a half ass job, but am beginning to think it is something serious. They all say it is fine, but the same stuff happens when the bike warms up. They have been through the electrical system and it is fine, and just keep scratching their heads and saying how weird it is. I have minimal mechanical ability, but am learning more watching these guys work. Any one have any ideas as to what could be happening?

I was hoping to take off through Oaxaca & Chiapas last Wed., and my buddies have already left me behind here in San Miguel Allende, Mexico.
Any help you could give would be awesome-
Thanks in advance-
michael

Hiya Michael, Firstly, to the HUBB!

What you are describing sounds like either Coil or Generator,(electrical anyhow) as you say it is OK for say 30 Mins or so ( till it gets Hot, Yes?) BUT then you say it starts OK again with the Choke........hmmmmmm.

Have you checked the Carb rubbers that connect the Carbs to the Cylinder head? No cracks / splits or air leaks? ( that get worse when she is hot)

Maybe someone else on here will have other Ideas, have you tried doing a search through the threads?

Martyn

Have you had a look at the air vent in the tank/ filler cap?
The best way to test it is to disconnect the fuel pipe from the carb and run it into a can see if the whole tank empties out at the same rate if it slows down then open the cap

It's not that difficult .... just difficult to find the problem ...

An engine needs mixture and needs a spark to run.

A. Fuel / mixture
So, you have been looking at the fuel system extensively, but let's talk about that one first.
- Fuel arrives in the carb? If you open the drain screw at the bottom of the carb float bowl, there should be about 15 liters per hour or 1 liter in 4 minutes running out of the overflow. This is approximate of course.
But, if the amount is much less, there is a problem somewhere: tank aeration, petcock filter, filter on top of the float needle
- Carb settings ok: did you change anything lately?
- Air filter clean and correctly fitted?
- Carb connections to cylinder head ok?
What was / is your fuel consumption; this bike does something like 1 liter : 20 km, if yours is far off that might be an indication of the problem.

B. Ignition
As per a previous post, the symptoms might be in one of the electrical ignition components. Best way is to swap them one by one for the items from a known good bike:
- Ignition coil
- TCI box
- Wiring (difficult to swap, check the wires for chafing and the connectors for cleanliness and tightness), and do not forget the sidestand switch, clutch switch, emergency stop etc.
- Stator: a bit of work but worth it. Another option is to measure it's resistance values when cold; if they are far off from the factory data this might be broken. Further, when your bike is hot the resistance value of one of the pickups might be way off from what it should be. So, ride till the problem occurs, stop, jump off and measure with a multimeter.

Good luck!
Auke

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Auke
http://aukemarieke.blogspot.com

Hey guys-

Thanks to everyone who responded, this really is a great site & a great resource for motorcycle travelers, I appreciate all your help.

The problem was a faulty wire in the ignition switch, They jumped the ignition, and left current on, and the bike did fine for 120 km!

So now just to see how to fix it, or buy a new one, and I am on the road-

Ill be riding a black XT through Southern Mexico and Central Mexico, send me an email if you wanna meet up for a part of the ride!

Ciao
amici

Just goes to show! just how HARD it is to 'diagnose' a bikes problem over the internet without touching, feeling, listening, SEEING the bike. I never woulda thought of the Ignition switch till last I suppose........ not with those symptoms.
Glad your sorted anyway!

Happy Riding

Martyn

Try replacing your plug cap??

Hairline cracks could be your problem