How common is kick back ?

So I am back tinkering with the 79 250 wr and I have been needing to re time the engine and so it was at 2.7 btdc and now its at 2 and seems to be a little smoother on the throttle and no decel knock (so far) but I rode it for a few minutes tonight then shut her off and waited 5 min. or so then tried a re start and it still has kick back not super hard but enough to let you know. It helps to start when you crack the throttle just a bit. Now keep this in mind I have only been in the carb just doing cleaning during the rebuild, I seem to remember reading a rich carb could trigger a kick back.
What are your thoughts on this and where to go from here ?
Bike cold will only start with the rocking technique , takes forever to get fuel in the cyl.

what pilot is in bike compared to stock? the rest of your kickback could be jetting. what is the spec for timing?

Thanks for the replies, I am not sure on timing spec I figured 2 would be good . I can go a little more on the plate if need be but not to much its almost at the end of the slot.
I will be checking carb next.
It never kicks back cold tho ?

On the pre '81 bikes make sure your clutch isn't slipping. You should have some play in the clutch lever on the case. If not your Center clutch rod needs its length adjusted.

If it's too rich on the pilot jet the sleeve is raised to allow more air to make it idle somewhat correctly. But hard starting also factors in when this situation happens when hot. Proper jetting and adjustments first.

Always wear your riding boot when kicking. Always bring it up to TDC then kick it hard. Don't be playing with it.

Note, on the bigger bores they will make you pay for soft kicking it when they kick back.

Does this motor have a keyway on the ignition? I have seen the keys get partially sheared enough to affect the timing. Especially if the bike kicks back.

The weather can really effect it when the jetting isn't even close. "Lean and its hot" when it's cold starting it's on the choke system it's rich.

main is 420
pilot is 45
needle is 6dh3 in middle groove
and yes the key is still good in the crank , I was in there last night.
It started on third kick tonight after the rock technique , rode for 10 min. shut off , let sit 5 min. then started on third kick hot and it was giving me some kick back but I was kicking this thing like a GDMF but it did start right up ?
I am going thru carb. right now .
The bike idles fine , sounds real good.

Just got back from a test ride, after cleaning carb and taking down numbers fired right up just fine w/choke seems nice and crisp now shut her down cuz I forgot to turn the fuel tap back on after it started. Started right back up 3 or 4 kicks not much kick back at all. I believe I can live with this much now.
What do you think about those numbers should I bother rejetting it does splatter the rear fender pretty good.

jet for best performance, never for spooge...

Yeah, that crap is hard to get off that white fender too.
I sure I will be asking for help on this . I guess the first thing is to hole shot in 3 rd and kill to inspect plug ?

I heard with this new blend of corn alcohol gas we can't read the plug anymore.

Husqvarna chainsaws is offering cans with 50:1 mix in it with the old blend os gas no corn alcohol in it. In the past sometimes my saws sat from spring to fall and with full tanks of gas they would start right up. Now with this new blend of garbage gas the mix lasts 30 days before the mix/gas goes bad. Having all types of equipment that runs on gas suxs.

not if you dont run ethanol...many stations carry ethanol free fuel.
http://www.pure-gas.org/

are you asking about jetting? generally you need to increase richness until four-stroking occurs, then back off a bit. plug reading is a complete waste of time.
you still need to find out exactly what your timing spec is supposed to be, and adjust from there...rather than assuming

Damn! This map shows exactly how screwed up California is. We barely have hit a few more places than Nevada that sell ethanol free fuel. At least two stations are on the way to one of the areas I like to ride at, but I don't get that far up too often. Thanks for posting that link.

Some South American countries are running on corn alcohol. We grow so much corn here why don't we do that in the us?

have you researched it? isnt corn ethanol bad enough?

there may even be some more places that have some that arent on the list...but its pretty thorough. i keep 15-20 gallons around all the time, as my local hookups all have 91 octane ethanol free.

There not using fossils fuels at all.

Because it takes more energy to make a gallon of ethanol from corn than you can get from burning it. Might as well just keep making fuel from petroleum as long as we have it; it's the most energy efficient and highest energy density source of fuel we have access to. If we used pure ethanol to fuel all of our vehicles, something like 97% of our land mass would need to be dedicated to corn production. That wouldn't leave much room for riding the Swedes...

(And if only I were smart enough, I'd be able to post a link to the 2001 Cornell University study that pretty much debunks the idea of efficiently making fuels from corn-based ethanol.)