The 74 DT360A is impossible to jet properly in stock form as far as I am concerned. Rich at low revs, lean at a cruise. Same jetting circuit, different result depending on RPM.

It can be fixed but ideally the factory wouldn't have left it to us.

Turbo Dan - you seem to be the most knowledgeable on the insanely complex and perplexing topic of the tuning of the DT360

I am in the process of resurrecting mine.

Short of "stuffing her" and knowing that i am going "straight stock" in all aspects, would you stay with 140 main and 50 pilot? Or would you bump up main? Also, what's your thoughts on needle being in stock "center" groove?

Thank you very much!

Martin

Umm.... maybe you typo'd but 140 is the DT250a main jet size. DT360 takes a 180 main and 50 pilot.

could be my memory
let me physically check what i have

Well I guess I know now why she melted



Obviously I will check pilot and needle. Does needle also have microscopic markings?

Needle jet should be marked O-8

Needle should be marked 5EJ8 Clip position is 3 from top (middle groove)

Both should also have the Mikuni "square in the corner of a square" mark on them just like the one that precedes 150 on your main jet.

Jet 0-8 (I need a new one :-) )
needle 5Ej8
pilot 50
all have the trademark too
thank you very much, bummed to find out my gal wasn't the virgin I thought she was, I guess everyone nearing 50 has a history

The 180 main should be about right. The stock 50 pilot is as close to right as you can get. It will still run lean at a cruise but there is no jetting that out. The needle clip position should be tuned for crisp low to mid throttle fueling. This range is also difficult to find a setting that works best for all engine speeds.

If you want to run it stock you will have to keep an ear open anytime you're cruising above 5000 RPM. The pinging below that RPM is pretty light and sporadic. It seems worst around 5500. Hopefully your build is tight as a drum, it runs perfectly and you never have to worry about it.

The very large tubes of JB Weld are about $15. You would love the difference it makes in the consistency of carburetion...

I'm not a big bore guru by any means but in my experience retarding the timing a little on the 360/400 works well. Still runs very strong and seems to rev out a little better in my totally unscientific seat of pants evaluation.

My go-to number is ~2.5mm BTDC or 0.100" BTDC.

YMMV

A little less timing helps avoid detonation as well. You will lose some low-mid though, and the DT360 is already pretty lukewarm down low.