Loncin desert storm has compression out the intake

[shitboxlover]

I have a 2008 loncin desert storm that wont stay running.

When it ran it ran rough and backfired a lot.

Now it will only start with throttle and there's a lot of unburned fuel (white smoke), there's also compression comming out the airbox. Is it the carburetor that is broken?

[Jacob Dellinger]

Need to do a leakdown test on engine. Also need to pull valve cover and check for a sticking valve. 

[davefrombc]

4  things  could  cause that problem.   Timing slipped   so  the  intake  valve   is  still partially open  when  cylinder fires ,  Intake  valve  is sticking slightly  open, rocker  arm   is too tight  and holsding  valve slightly  open  and finally,  a burnt  intake valve valve allowing  combustion gasses  to  blow back.

Most  likely  is a timing slip  or  valve  lash on the  intake valve is too tight .

 

[shitboxlover]

Thanks for the replies, i'll be checking that later

forgot to ad that it runs really well for a couple of seconds before the fuel runs out/empties from the carb. 

[Riki]

maybe your intake valve has burned, have you adjusted valve play?