lumpy mk1

Just got my mk1 1800 it is lumpy until about 3000 they goes like stink ,It has got new dizzy cap rotor etc ,So i was wondering if it could have a cam or is their something else to check cheers simon

Timing and mixture, would be the initial things to check. Also (doesn't really affect the running unless its been neglected) - when was it last serviced? Is it the same during warm up or only once warm?

It had an oil change and filter cleaned ,Yes it is the same warm or cold ,did notice a slight blowing from the pipe underneath (which is a full scorpion pipe i think)if that alters enything

It will indirectly - in that you can't get a decent reading off a gas analyser (or wideband) with an exhaust leak.

as said, check timing and co. sounds lean to me.

Cheers folks i will give that a try a the weekend see what happens