How much money should I pay a certified mechanic for a top end overhaul on a 1978 Honda XL 250s?

Or a similar dual sport motorcycle for comparison…

I was told he is performing a top end overhaul (replacing all gaskets and rings on piston, cleaning everything, installing a battery, replacing compression release cable, replacing cylinder head, draining all oil/replacing). He indicated a previous owner put goop on the engine that he had to take off and it needed a lot of cleaning.

Is this everything that entails a "top end overhaul?"

Parts supposedly cost $150, what should I pay for labor?

Added (1). I should've clarified- Its not a certified honda shop, but it's a retired honda mechanic who still has his honda certificate. He works as a mechanic out of his house (small scale). Not sure the 7 hour rule would still apply? I'd LOVE to learn how to fix this bike! I'm so new to all of this and it's my first motorcycle. I'm even still learning how to ride it. Where can I learn to fix these old bikes? But, anyway, assuming he is a "local mechanic" would you think 350 labor is OK "top end overhaul"?

Standard rates in my area are $85/hour. Find an independent mechanic, though. Certified Honda shops are crooked beyond belief. If they put in 5 hours of work, you will be billed for 7, guaranteed. I own a 1985 Honda Magna, and the Honda shop is just a few blocks from my house. The started off by refusing to work on my carbs, and then everything went downhill from there. I buy parts from them, but I won't have their service shop even look cross-eyed at my bike. Sure, they can do the work, but the value just isn't there. I have a good friend who is a Honda certified Master Mechanic, and he quit over their business practices in Bend, OR. He once did two hours of work, billed for two hours, and got reprimanded. The shop here in Nampa is the same way, and I have since heard that every single one is. Basically, the consider every single job they take on to be 7 hours of labor and are discouraged from taking jobs that are less. So if you have them do ANYTHING to your bike, here is what you can expect to pay: 7 x $85 (or whatever your local rate is) = $595 + $50 shop fees + parts (let's say $110). 595+50+110=$755. You can easily find a good independent shop with certified mechanics who will do the job for less than half that. I did not. I have been learning to do it on my own, which is what I would suggest you do. It's your bike, meng. What are you going to do if it breaks down on you 50 miles from nowhere?

Get the shop manual and do it yourself, you got all winter

The year and value of the bike has little influence on the labor to do the job. You are looking at at least 6 hours labor plus machine shop charges for a valve job.

I'd suspect you are looking at $650.00 plus the $150.00 in parts you list.

If he will do it for $350.00 that's a really good deal

I recommend you learn to rebuild the top end yourself. You may end up paying $600 for something that costs $160 and a few hours of your time.