It turns out the overheating problem I was concerned about was just my paranoia running away with me.  I've had the bike out several times this past week and the highest temp I've seen was 367 F and that was only a one time occurance, haven't had it that hot since that one time. Depending on how I'm riding it at the time the temp is normally about 300 -350. 

Once the Trail Tech satisfied me that my new engine wasn't on the verge of melting I've been able to ride it for longer periods of time and have been experimenting with carb and timing adjustments trying to find that perfect setting.  Been all over the place with air screw settings and looks like manual spec of 1&1/2 turns out is about as good as it gets. Reset the timing at ,100 BTDC but to be honest that didn't seem to make any difference at all, none that I could tell anyway. 

I should back up here a minute and let you know what I'm dealing with.  The bike is now starting on first or second kick, hot or cold. That's a big improvement in itself. It idles fine and has great response when I twist the throttle whether in neutral or under a load. I've been keeping it under 5000rpm out of an abundance of caution since everything is new in there but feel that it would rev right on up to redline if I asked it too. The only thing that's bothering me is that it will not run steady at a constant speed, any constant speed. As long as it's under a load and increasing in speed all is great. 

But once I get to a certain speed, any speed, but lets say 40, which is a speed I like to cruise on the old blacktop  here , it will start to get jerky on me, jerky, yeah, that's the best I can describe it, kind of feels like getting on and off the throttle or on and off the kill switch maybe, hard to describe really. If I then give it a bit more throttle it evens right out and goes great, until it reaches a steady speed again, then starts all over with the jerkyness. Can't keep going faster and faster and faster just to keep everything happy so what I've been doing is just pulling  in the clutch and coasting for a bit then  back on the throttle again. Just read what I just wrote and it's not really as bad as it sounds and I can live with it but will definitly keep riding it and playing with things with the hope of smoothing things out eventually. 

Until a few weeks ago I hadn't been on this bike for 30 + years so my memory might not be complete but I can't imagine that I wouldn't have noticed or that I'd have forgotten about this jerkiness if it did it back then. But then again, maybe it just didn't bother me then like it does now... Honestly don't know. 

 Couple more things to add, is that if I let off the throttle completely the jerkiness gets even worse. Spark plug looks pretty good, bit rich if anything.

Congratulations on bringing it back!

Sounds like you're describing the "Yamaha 360 curse".  Some do the surging worse than others. 

Thanks Mark, this site made it possible. I've been reading about the DT 360 surging, bucking, jerking problem that some others have had and feeling lucky that mine never did that, but apparently it does now. Still can't believe I didn't notice it way back then or that I'd have forgotten all about it. Might have something to do with the way I ride it now vs the way I rode it back then, don't know, or maybe something to with increased compression now after the rebuild, may never figure it out... Be nice if I can sort it out but either way, great to be riding it again, even if it is a bit quirky.

Well done Jack, great work! 

You've gone from wanting to get it back running, to getting it to run perfectly!! 

Well done Jack, great job!
On your point about surging, here's a similar issue I have with my RT1.
Have a read of the Yamaha bulletin MarkT posted in one of the responses.
My RT1 is worse now and still has an air leak, which I have a plan to deal with.
www.yamaha-enduros.com/index.php/forums/...elp-required?start=0

"You've gone from wanting to get it back running, to getting it to run perfectly!!"

LOL! Funny how the goal line keeps jumping ahead as we work our way up the field isn't it. Thanks Al.

Thanks Pete! Interesting bulletin. I thought the surging issue was only with the 74 DT 360, hadn't realized it was a known problem with other big bores of that era. Kind of discouraging to think I may not be able to find a cure but it is what it is I guess.

What puzzles me most is that it apparently doesn't effect every 360, some don't have this problem from what I've read and what's more, I honestly don't think mine did this back in the day. Not really something that a guy wouldn't notice but can't say for sure....

But back then I rode it almost exclusively out in the field and woods back of the house, rough, bumpy terrain with lots of cornering, hills, rocks and trees to navigate around and through, so getting on and off the throttle constantly with very a very limited amount of time at any steady speed and nowadays I ride it at much milder pace and spend more time on the blacktop than I do in the field so always wanting a smooth steady crusing speed, which just isn't there. Don't think I'll try the porting change or the piston mods, not for now anyway. But will keep riding it and keep fiddling with things and maybe stumble onto a fix. What's that they say about even a blind hog comes across an acorn every now and then? Never hurts to keep trying.

Hope you get your's running better, know you'll post up with any improvements so I'll be on the lookout for it.

I have a DT360 tank in very good shape, except for a small ripple, from my first motorcycle. I put it up on the classified area of this site but got cold feet and took it down. I have been looking for a DT360 to restore at some point and decided I should hold onto it. Seems you're only looking for the cap and lock anyway and this will need to be re-chromed. I also really don't know my values so thought I should hang tight until I know more. Some are asking quite a bit for rusty, dented pieces.

Jack - great work on the bike!
I have the surging too, I have learned to live with it, going faster and upshifting always helps!
what i found is that I am never "done" continually improving and enhancing my bikes and this for me is part of the fun
I am on the hunt for another project....perhaps I should buy a nice tank on eBay and build a bike around it

Hi Adguy, I have everything I need for the tank now. One of the members here, LDW72120, very kindly donated the tank lock bracket I was looking for and I got the tank damper off of ebay.

Your tank looks pretty good, lot better condition than mine when I started the rebuild. I'd hang onto it for sure if you hope to get another 360. Good tanks are scarce as hens teeth and priced accordingly. If the bike you find turns out to have a good tank you shouldn't have any trouble selling the one you have now. Good luck in your hunt.