I am aware that the redline on the 360 is quite a bit different from the smaller bikes, and I'm not suggesting there is need to hit 7500 like you easily can on the smaller bikes.
What pollution controls were instituted by then that would hold back the performance of the bike?

This is from the 1971 Cycle World test:


The same article mentions good enough power to be competitive in the 360 motocross class with the muffler intact. Unintentional wheelies in the lower gears. That all sounds about right. Something definitely changed mid 70's. Same bore and stroke, same compression, same fixed timing. Had to be something else.

The 74 360 actually has some advantages over the older models. The six petal reed is an improvement. Maybe not up to modern standards but it's better than what the RT360 had.

Other than crankcase volume there's nothing wrong with it. Only problem is that it's kind of a pain in the ass to correct that issue.

There has been ALOT of DT360 threads in 2020. Seems every week there's a new, different thread, bringing one back to life after sitting, restored one & found another to restore from the scrapyard. More DT360 this year than I can remember. Or maybe I'm just forgetful. But I digress...I would have to expect that if the magazines in the day noticed the surging, part throttle unstable running, that, except for Turbodan, all DT360 owners in this forum do too?

This is a great thread.

I would love to see some magazine reviews of the 74 DT360, by the way, if anybody knows where to find them.

Regarding performance, don't forget that some of us are getting towards twice the weight we were back in the day! Just cast your mind back to how much carrying a pillion would affect performance back then - that's almost the same as what we're doing when we ride them now. And yes, I'm sure that there are some super, lithe sixty somethings out there who are "as fit as I've ever been!"

its all muscle on my end
there is a review from 1974 that another enduro genius shared with me a while back that described the way this insane bike ran when new...the insane pinging and bucking at low load. So once I got mine to run like this I called it a day on trying to tune this craziness out and just decided to enjoy the ride, taking care to hold on tight

In comparison to the DT3 I rode in high school and shortly thereafter, the DT360 is plainly better, overall. The suspension, lower CG, lighter clutch pull and the engine pulls much stronger. As it should. The surging I've read and heard about hasn't been a distraction with my experience with my current 360. But the pinging is. Maybe just because I let it! Truthfully, when one works to find the right, parts, people, tools and procedures to thoughtfully build one of these vintage engines, it is disturbing to hear the pininging. I can't help but think that it is not the best kind of noise any engine should make. And the catch is you can't just go easy on the throttle and "baby it" as they say, because that is the condition that amplifies it.

And it's not some much the audio part of the condition that is disturbing, it's not a loud pinging. It's the fact that it is occurring at all (while your being gentle) that's bothersome.

An interesting point by MarkT about performance improvements over the last five decades. I'm not a Corvette person, but a friend was telling me they can be factory ordered with an engine producing over 700 HP.

I haven't ridden mine in thirty years and my memory isn't what it used to be but I honestly can't remember my bike having these symtoms. I can't say that it didn't have them it's possible it was all taking place with me blithfully ignorant that it was happening. But from the descriptions given here it's hard to believe I wouldn't have noticed it. But anythings possible. Only thing I know for sure is that I loved riding it and if it was underpowered I never knew it.

It may have something to do with the fact that I never had it on the highway, ever. We basically live in the woods and these woods is pretty much the only place I rode it. I also had worn a path around the perimeter of an old field behind the house. I probably spent more time in the lower gears than most of you so doing so maybe kept the revs up high enough that the bike was never or seldom in that light load spot that you talk of. I don't know, just tossing in my two cents since I own one. You guys know twice as much about them as I do now and a hundred times more than I did back then so I don't claim to know what I'm talking about, just tossing in my 2 cents since I do own one.

I'll for sure be paying attention and listening and looking for those symtons once I get er running again. Shooting for spring!

I'm loving this whole thread. Thanks guys.

That RT1 article and spec sheet is very interesting. (The link wouldn't work for me when it was posted... probably all you guys hogging the bandwidth! )

What I found interesting is I have some other magazines from that era... Nothing with the RT1... but the 1972 TS400 for example had a 0-60 of about 12 seconds in Cycle Magazine and they touted it as being the "best engine in its class". Quarter mile was 16.45 sec at 75.45 mph. They did the road portion of the test along with a Suzuki 550 and ranted and raved at how the TS400 kept right up with it.

I think the RT1 is a bit lighter than the TS400 but more than twice as quick from 0-60? That's hard to believe.

72 TS400 specs in the magazine I have are more in line with the later DT400.

Again, I'm not a "big bore" guy but I can't imagine Yamaha would have a 360 loose that much performance... almost 3 times slower 0-60 vs. the DT400 a few years later? This might be a case of bad data in the magazine reports? I really don't know. Maybe some of the guys here that own or have owned a lot of the larger bikes can comment on if the RT1 accelerates 3 times quicker than a DT360 or DT400?

Next big ride we'll have to have the RT1's drag race the DT400's!