I have worked out how to post images ,here is an image of my bike I am posting this because I was told my side panels could be forming an air vortex around the air filter at high speed

the bike is an 86 model it was imported from the U S in 96,when I got it had a Voodoo slash cut exhaust ,pod filter ,stock carb rejetted to suit mods ,it would hit about 85 mph
                    I got a 94mm piston off Lancer and a D R cam from a 1990 model ,my mechanic said he did a stage one head job lapped the valves ,increased the exhaust port to 1.5  inches before he put the new cam and piston in ,
                     with these mods it still only hit 85mph ,so I purchased a V M 38 mm carb with a size 20 pilot jet and a185 main jet the bike would hit 80 mph in 3rd gear but it did not increase in 4th so I have tried a 200 ,a 210 and a220 main jet it made no difference, next I put the new exhaust on( I now have a 200 main jet and the clip on the needle is on the top setting) the new spark plug has gone black and sooty straight away so I assumed it is running way to rich.I said to my mechanic to put a thicker needle in it but he said a smaller main jet would be better.
                       I am taking it to the mechanic monday as it is to cold here to work outside ,where should the mechanic start

So we do know that the ignition system parts all worked together and are properly matched.........so a mismatch of early and later parts is not an issue.

The stock carb works well with piston/cam mods you have done, and when I made the changes there was very little need for jet changes - the engine ran very well with the new piston and cam.  The Mikuni VM carb does provide a more responsive carb - however the stock carb still allowed the engine to make good power.  The fact that both carbs have not allowed the engine to run well indicates to me it is not a carb issue).  (It does not sound to me like you are having carb issues - it should run pretty well with the standard jetting and only need a small amount of changes in jetting size).

Have you confirmed that the compression release cable is adjusted properly and not holding the exhaust valve open a tad?  You can disconnect the cable and take a test run to confirm the compression release is not the issue.  In 99 out of 100 starts the engine will start without the compression release - the starter cannot push the piston up over TDC if the piston was on the compression stroke when you pushed the starter button - most times the piston was on another stroke and the engine can spin over and start without using the compression release.  If the engine stops turning over when you push the starter button - release it, put the engine in gear, and rock it forward until the piston gets off the compression stroke.....then put the transmission in neutral and push the starter button.

Oh my, that's not lookin too good NBJ.  Do you have any idea what happened?  How does the camshaft look?

Thanks for the picture.  Could you also post pics of the cam and the profile of the rocker arm pad so we can get a better feel for exactly how much of the follower pad is worn away?

You mentioned that a mechanic was doing the work for you.  What does the mechanic think happened?  You also mentioned that the DR cam was from a 1990 model.  Was it a used cam?

Yikes!

the cam is shot as well ,yes it was a 2nd hand cam but  there was  plenty of oil so the oil pump is fine
                        My NEW mechanic said the case hardening on the rocker arms was probably worn thru when the old mechanic fitted the D R cam and the roughness has ground down the already worn cam.
                       So I have learnt my lesson and have ordered new parts ,when they are fitted I will send pics of the old parts

This shot shows the brazed pad.

I had the holes drilled into my D R cam before it was fitted and here is the rocker I have ordered if it is the old stock it is to late as I ordered yesterday and paid for it