Setting up Valve Clearances - How Important

[Animammel]

Hey guys, been having a lot of trouble my with 88 zx400 and its sitting with the mechanic at the moment.

She wont start easily and if she does with quick start down the carbs she would just die whenever.
Carb is completely set up and clean.
Changed out the CDI.
Set up timing and the marks line up on the head.

So now, when my old man rebuilt the motor, he forgot to set the valve clearances. How important is this and what would be the signs of it being out.

I cannot think of what more to do with this bike and now its costing me more than I would like and the little time I have to work on the bike is/was not helping.

Any suggestions?

[RedexRobB]

They are worth checking just to eliminate them.

They will cause starting problems if not adjusted but as far as i know they wont cause it to cut out whenever it feels like it.

[ross46]

check and change if needed, you will be glad you did, I had 6 slightly out on the exhaust side, changed them yesterday, on my way home I went down the road I normally do which has a hill which goes up then is quite steep the other side, been going over it for 6 months, then today, went over, shut the throttle ever so slightly over the crest and pinned it on the way down... Then shat myself as it popped a wheelie the whole way down has made the bike soooo much nicer