All chnaged!!! The bike is lots better but still not 100%. I think it is going to be a case of a slight niggle that needs to be lived with!!

you can pull the lead off cylinder 3 when the bike is running at it dies. pull it off cyl 4 and it continues the same. its got my spare motor in it so surely 2 engines cant have the same fault. runs sweet as a nut as soon as you set off. checked all valve clearences on both motors and are both spot on. got me stumped. also swapped leads 1 and 4 to eachothers cylinder and no .different. with the airbox on if you cover up the inlet then it appears to jump onto 4cylinders. this is the same when the airbox is removed and you cover up carb 4. do it on any of the others and the motor dies. cover up the rhs airjet on the bellmouth (on cyl.4) and it appears to go on to 4. baffling me pardon the pun

mines doing exactly the same!!!!!! and it's just had the valves done! not so much of a problem on track as its always revving but if you find the solution let me know!!!

Got us all stumped, prob the diesel ya little bro has been filling up with

It sounds like a pilot jet problem,won't run in the Idle department but will above it.

Replace the airjet ? ... it sounds like the mixture is off in that cylinder.

Do you have a colour tune kit ?

whats a colour tune kit?

http://cgi.ebay.co.uk/Gunson-Motorcycle ... 215003r519" onclick="window.open(this.href);return false;

It replaces one sparkplug and allows you see the colour of the ignition flame - yellow is rich dark blue is good light blue is lean .... it might help to see if this cylider is running differently to the others

thats not actually a bad idea evil, thought about changing the airjet to see what difference it makes. it will only richen the mixture at worst so it wont harm anything. its just if it runs ok when warm. still by doin that its compensating for something else, so id like to find out the real problems ideally