My DS650 takes FOREVER to start when it is cold. the jetting should be about right, but it never wants to start, sometimes we even have to change the plug, and flames come out the muffler. My Raptor starts 10x easier, and it doesn't even have the decompression release. WTF?

 

When it cools off you usually get lean and have to jet up. From what I noticed the other day though it was running extremely rich, that's why it would backfire thru the exhaust and foul the plug.

 

My brother's DS is the same way it cranks and cranks but always ends up starting, my Raptor is just like yours touch the button and bang fires right over. I just dropped mine off yesterday to get a stage1 cam and high comp piston put in. I am only going 11-1 on mine. Can you run pump gas on yours at 12-1? The only thing I am afraid of is mine runs mint now, never hesitates, starts right up good power throughout, just needed a little more and I am praying it will run just a nice with a little more oomph.

Nocando

 

I can't run pump gas, it starts pinging. Seems to need at least 97 octane.

 

My DS is also extremely hard to start, and i worry that the starters going to wear out. I was told not to give the thing any gas when starting because it screws up the timing. I just pull the choke all the way out and hold the starter for a few seconds and it usually works. If you find a better way, please tell me.

 

sevenac, i've never heard that b4 and i've started my ds tons of times while giving it gas, haven't had n e problems yet

 

I only have to give it gas when its cold but when its warm all I have to do is just push the bottom and that usually does the trick.

 

My DS starts fine, but it will not "take gas" until it has warmed up.. It bogs and sputters, but once it is wamr its fine... Awfully wierd and I have noticed that loosening the gascap helps a bit.

 

Backfiring out the tail pipe when you attempt to start it usually indicates an ignition problem. It takes gas to create the back fire so you are getting gas. By the time it does fire there is too much gas in the cylinder to ever start so all it does is ignite the gas vapors that have run into the pipe.
You probably have a weak spark and when the engine is cold its not enough to ignite the unvaporized mixture. When an engine is warm the fuel vaporizes much better and is much easier to ignite, the engine starts easier.
So whats the problem???
If you hadn't said that you replaced the plug/s that would be me first suggestion, hopfully you replaced both with new ones. If not try that, if one plug is fouled they both are.
You have two seporate coils so its unlikely they are the problem.
You may have a dying CDI unit or pick-up coil. If you have a friend with a DS, borrow his CDI and try it on yours but swap it before you attempt to start it cold.
You can test the pick-up coil with an ohm meter but somebody with a shop manual will have to give you the specs. Anybody on here have that???
Well thats my .02 good luck

 

Quadman650's is on ALKY and so far in 50 degree weather it seems to crank up within seconds.

Sounds like you other ds guys need to listen to the motor a little closer. You have to listen to hit and then just tap the throttle and it should pop off.