Spring like weather has allowed me to do some riding and evaluate a few changes made over the winter.

The first change was to add the Trail Tech digital temperature gauge. The sensor ring was mounted under the spare spark plug blankoff bolt in the cylinder head.

 

The Pennzoil 2 stroke oil was drained from the tank and replaced with Yamalube. The Pennzoil drained out very slowly from the feed line of the autolube pump. Partially because it was cold when this was done and partially because there was a waxy partial blockage at the end attached to the oil tank.

A spare carb was modified with the Thunder Products Torque Wing (sounds like a product marked via JC Whitney or on late night TV) and the partner part, the UFO for the slide. The main jet and needle clip position were left stock and the pilot was changed to a 27.5.

The compression release valve was locked tightly shut to eliminate the possibilty of it contibuting to irregular running.

Other than a noticable improvement in carburation at lower throttle openings, the engine exhibited the typical mild pinging at part throttle once above 320°F. Below this temperature there is no pinging, above 320° the sensitivity to pinging increases in amplitude and range of conditions (throttle position, load, RPM). The 3500 to 5000 RPM range seemed to be the noisiest. And this was at small (3/16 - 1/4) throttle openings.

The fuel was 93 octane non-ethanol fuel. Remember the head on this bike has the Harry Klemm squish band modification and Sleeper Pipe

The timing was checked while hot with a timing light and found to be triggering properly.

Next step will be to retard the timing slightly and retest.

I like a timing setting of 0.100" BTDC on the big bores.

even thought I dont ping, i recently dialed mine down to 0.100" and it made things "nicer"

question for Mark / others...if decompression valve were to leak, how would this impact performance?  I cleaned mine up real nice when i rebuilt so i dont think it is leaking but curious nontheless based on prior note

I've run with the lever pulled...  Try it and see.  Maybe a little "softer" at low rpm but really hard to tell a difference.  

That might be tricky - valve operation is linked directly to the kick start (we are still talking about the DT360, aren't we?). 

You guys make things so difficult...  okay.  Go buy an RT1, RT2, or RT3 and try it then.  

If I ever get my RT2 and DT360 on the road, I promise to let you know which one it's easier on! Maybe I could get Gr8auntiepat to ride pillion on the DT360 (she's not a big lass, so should be possible!), and lean down and pull on the cable as we're riding along!   That sounds so wrong, doesn't it? 

Thanks for the wisdom on the timing setting. 


A little DT360A porn to share...

  

Double text happens when using the "insert all" button for pictures/attachments.  If you use the "insert" button next to each individual attachment it doesn't double the text...  known glitch in the forum software.

Right,I have read this post with some facination.
Why? It's an annoying and mundain subject but an answer most who have this problem are looking
for. 
So i have competition trials bikes and ride competitvly.
The TY Yamaha " Pinky" 250 can suffer from the symptoms encountered here. You can hear them clatterring at certain on off throttle conditions even on the over run .
Somewhere,i have an artical by Stan Stephens in a small UK publication just for trials and enduro bikes.
There are fundemental conflicts in the design and no one problem but rather a culmination of several creating a condition.
Knock knock ! whos there ?
What he did was put a brass insert in the head,completely change the exhaust port design and angle of exit,of course that included welding and engineering, altered the cases and transferes and increasing the capacity to 270 from 250. A change of carb . The pipe was re formed and the bike belongs to (or did do then) Nigel Birkett.

They got an expensive result but that problem had existed for ages . 
Intersesting to a degree.