difficulty starting wont rev over4000 revs back fires front 2 pipes glow red hot after 2 min on going prob have changed all ignition parts but still happaning

dont run it anymore. you might be doing irrepairable damage to the engine.

Please provide a bit of back-story.. how / when did these problems come about, what exactly have you changed.

Has it been standing etc etc.

If the exhaust pipes are glowing it's either burning fuel in the downpipes (bad) or its running very lean (also bad)

It could be too many things to specualte without a bit more info... heres just a few of them

Knackered head-gasket
Duff plug(s)
gummed up / stuck carb(s)
broken valve(s)
faulty coil(s)
Faulty Ignition lead(s)

Give us some more info and we'll see what we can do :-)

Eitherway don't run it anymore till its fixed!!