Hello,
I am the happy owner of a 94 Xt600 with 03 motor carbs etc.It is a complete modification with k&n filter crd exchaust otherwise stock.(12000km)
Here is my problem.
The bike runs fine exept on high rpm and close to full throttle opening it accelerates well but when i close the throttle a bit to ajust my speed it stalls and i have to open the throttle completely for the motor to come to life again.
the problem appears at any gear and it is a bit strange because i have
to ride using the throttle like an on-off switch especially at high speeds.
I have tryed to eliminate all the apparent simple causes like loose wires
dirty air filter etc.
Any ideas please reply thanks.
ps. I forgot to mention its a bitch to start in the morning.

a new problem ...
I can't really develop a theory about what happens, but it might be that you have opened up everything with the K&N and CRd exhaust and that the carb setting high up is too lean. Too check, raise the needle in the secondary carb one or two notches. While you're there, check the membrane, slide and butterfly valve, mechanism.

Bad starting: adjust the pilot mixture screw till solved. Yes, a bitch to reach ....

Auke

__________________
Auke
http://aukemarieke.blogspot.com

I have an XT600E 1993 (Italian import) and I have a damaged Carburettor Inlet Rubber. Does anybody know where I can buy these spare parts from in the UK? The 2 Yamamha part numbers for these 2 Carburettor Inlet Rubbers are 43f-13586-01-00 and 1vj-13596-00-00.
I hope someone in the UK can help me

Hi I think Fowlers are the UKs main Yamaha spares supplier.

Fowlers - Genuine Spare Parts

Thanks for the reply.
Im going to try raising the needle next weekend and post reply.
I also have some questions regarding technical info about this bike
to ask in a new thread.

did you increase the main jet size?

Thanks for replying.
I opened the carbs today and here is what happened
I noticed that the 2 colars connecting the airbox to the carbs were gone. I used a couple of tie raps temporarly,raised the 2nd needle 1 slot,cleaned the air filter and the bike runs much better now!
It runs and sounds better,pulls harder and that got me thinking maybe
It was running way lean all this time.
A part of the stumble is still there but at a smaller rpm range.
Id also like to ask if i should change the main jets and what size to use.
I also noticed the carbs are like new inside and the sync is fine at ~6mm
but at w.o.t. the butterfly was open way more than 90 degres.
Im no carb expert but i know for fact that cant be a good thing for airflow.
So i was wondering what would happen if i align the plate to be verticall at
wot but i left it as is because like i said i dont know lots about carbs.
The mixure screw i found but couldnt reach it.next time.

seems to have been the problem. Shorty of measuring the mixture (exhaust gas analyser or lambda sonde) you can experiment a bit: raise the needle in the second carb one notch extra, or raise the needle in the first carb one notch.
Also, make sure petrol flows freely to the float bowl.
Do not worry too much about the buterfly, you will not very often use that throttle setting. If you insist on worrying; the butterfky should be horizontal when first stage slide just not covers any of the channel area, after that point there is another 5 mm of travel that is irrelevant.

Auke

__________________
Auke
http://aukemarieke.blogspot.com