Engine rebuild, first oil change.

New Bike or Build? generally I've heard 500, lots of guys will
cut open the filter to see if there are any metal bits... To me that's a bit overkill
500 to 1000 with new oil, then get it changed over...

MIght be fuel mix is too lean, give it a bit more fuel to cool it down
doesn't hurt to run a bit rich but it can hurt to run too lean...

Run Synthetic in it after the breakin, Mobil 1 V-twin 20W-50
that should drop the temps as well and keep the engine cleaner..

Synthetic motor oil is a good idea and the restart when hot issue could also be jetting. I just went through that on my 95 inch Springer and the jetting solved that issue.

+1
500 miles and switch to synthetic. I prefer to run my jetting rich on a new build for the first 1k miles to avoid any lean overheating issues.

Not to ignite any debates but synthetics work just fine in a Shovel and most companies make a single viscosity synthetic oil you can use if not wanting to use a multi weight oil. I used 60w synthetic in my previous Shovel and would ride that bike hard through the desert without issue. On cooler mornings it seemed to kick over better as well when using this instead of a heavier 70w dino oil.

Point well taken if your builder wants to warranty based on the oil used. I would only add that a shovel's design regardless of how long it's been around doesn't mean it cannot benefit from an improved oil. Does it need it? Nope, but neither does a high end newer design engine when it comes down to it. The reason newer engine builders and racers use these oils is because of their ability to hold up under extreme conditions for greater periods of time and sludge prevention to name a few. Just my opinion, but for the amount of money I spend on my bikes and vehicles the extra cost of a synthetic oil is not going to break the bank, and should squeeze a few extra miles out of them to boot. If it works for you, cool.

well of course I'll drop in a couple of cents worth
newer cars/bike need syn, they have very precise
machined parts very tight tolerances and oil that
can get through easier lubricates faster, better, longer

Heres the thing, 60 wt syn is no different in viscosity
than 60 wt dyno it's exactly the same weight however
the syn lasts longer, cleans better and at 5K will be
in better condition than the dyno, it's why we don't have
to do 2500 mile oil changes, period, and because it
maintains its properties closer to new longer
it works better.

Ya do whatever the warranty giver tells ya, but 70wt is
overkill,

Not sure where you got that but it's the old wives tale, roller bearings won't skid with synthetic, I know a local wrench that was telling me that and how he made a guy pay twice for a rebuild because he ran synthetic and had a bearing go bad.

The fact was that he had installed a bad bearing, he just shoved up this guys tail pipe in order to cover his bad work....

Remember synthetic is no more slippery than dyno, the viscosity is exactly the same, the difference lies in synthetics ability to maintain it's properties longer, better oil means the oil detergents work longer, keeping things cleaner, because the oil doesn't break down as quickly as dyno it lubricates at 5K like it did at 1K.

Dyno doesn't do that, it can't withstand the temp changes for as long a time as syn, so it does degrade in its ability to lube and clean.

If the guy that built your engine said to run 70 then run it if that's what he
requires for a warranty.

The only straight weight syn I know of for bikes is RedLine 60wt syn, I ran it for a while in the softail one summer to see what it did, and frankly, nothing was gained over the 20W50 syn..

Agree. The thinking about synthetics and roller bearings was disproved years ago. An old wives tale passed around by old mechanics that had zero science behind it.

And nooooooo, lets not start the syn vs Dino debate again

here's a link to redlines 20W60
http://www.redlineoil.com/product.aspx?pid=111&pcid=13

Amsoils straight 60Wt Syn

http://www.amsoil.com/shop/by-product/motor-oil/motorcycle/synthetic-sae-60-motorcycle-oil/?code=MCSQT-EA

Being in FL the straight weight will work, however I'd bet the bike would
start easier on the multi viscosity oil and the 20W would get moving faster through the oil pump and ports than a straight weight oil but that's JMO

Remember I didn't sleep in a Holiday Inn last night...

I think you'll be happy with a 60w compared to the 70w.