So my DT360 has a new issue since I tried to start about 2 years ago. I'd appreciate help with the sequence to diagnose and isolate the problem.

cleaned carb, adjusted float, new gas. Running Rex's Speedhop CDI.

Here's what's happening:

-choke on.

-open throttle a bit

-kick, kick, kick, hard kickback.

kick, loud backfire in the exhaust.

kick, start. Runs fine.

Any ideas on how to go about taming the kickback and backfire? And in what order to approach this?

Thanks.

I can't answer your question, but it might help others to if you could let us know if you are running points or CDI (a lot were converted to points). If CDI, original Yamaha or aftermarket replacement?

Thanks.

Ah yes, that is important. I am running the CDI from Rex's Speedshop.

The DT360 has a decompression valve on the cylinder above the exhaust, if not working It will kick back. There’s a cable that connects the valve to the kick starter mechanism.It releases a small amount of compression so it kicks over easier

Best to not open the throttle with the choke (enrichener) as it doesn't work as well with the throttle open.

I'd test the timing with a light when kicking it over... sounds like a timing issue to me. People have had mixed results with the Rex system.

My DT360 has a functional OEM auto compression release, but it will kick back if I open the throttle at all when kicking it over. I actually place my throttle hand to the left of the grip so I don't inadvertently open it up at all.

My DT360 with a VAPE (PowerDynamo) and the decompression valve working good it kick and starts very easy, usually two kicks.

Does your 360 ever kick back?

No, does not kick back, like MarkT suggested, check the timing. Those decompression valves get gummed and don’t work properly. I will try to find a picture of one I took apart and rebuilt.
Do a search for” 1974 Resto, DT360”, it will be on that somewhere.

First & only thought if it's backfiring in the exhaust & kicking back--is--The Flywheel key is Toast. Sorry but i haven't read the story very thoroughly just now.