Hello there people, new to this online thing.
almost as new to me as trying to fix my girlfriends wee brothers quad!!
the problems are as follows , i hope somebody can help.

the carburetor seat had lost its metal intake valve, so we ordered a new one and although i can get the quad to start, when its warmed up there seems to be a backfire issue and eventually it will die.
should there be a pipe attached to the valve on the carburetor seat or just the metal bit poking out?
could the compression problem be a blown gasket?
i know thats very vague, hopefully somebody can help.

thanks again

grant

Scotland

p.s i cant find a manual for loncin 200/250 quad anywhere can u suggest somebody/somewhere?  

if you have low compression first thing you need to do is to adjust the valves, set the valves at .004 intake and .006 exhaust.
i have no ideal what you're taking about on the carburetor, you need to do a little better job of explaining what you need to know  

by seat are you talking about the jets?

the pilot should only be a brass pilot jet, approximately 1/4 inch in lenth, by 3/16 inch in diameter.

the main however can have a tube with holes in it and normally does although some can be smaller than the pilot jet and fit down inside a tube.

yes please explain exactly what you mean on the carb.  

the bit im talking about is on the thing that mounts the carb to the head. on it is a brass pin/valve, is that the pilot and should it be exposed bare or have a pipe attached?
Because as the last one had fallen out i dont know whether there was a pipe attached.
im finding it hard to describe as im a complete beginner.
i got it running ok, only for it to die after about ten minutes use.
it tends to spit/backfire just before it dies.
is this something to do with the engine overheating i wonder?  

if you are talking about the top of the carb where the round slide goes in and has the pilot needle on it then it shouldn't have a sleeve on it.
it is guided by the pilot jet and the carburetor housing.

if it is spitting and backfiring you could have the fuel /air mixture too lean.
are you sure you put the clip on the new needle in the same groove as before.
if you put it on a higher groove it would run a little lean.

or it could be as simple as the fuel/air mixture needing to be re-adjusted.
the fuel/air mixture screw is either located on the side of the carburetor or the bottom of it.
turning the fuel/air mixture screw to the left will add more fuel to the mixture. while turning it to the right will decrease the amount of fuel in the mix.

any adjustments made to there should be small increments and you mark where it is setting originally and keep up with how many turns and in which direction you make them.
that way you can get it back to where it was if necessary.

not overlooking the obvious i need to state that the timing can jump on these, and that also they are very bad about breaking the valve keepers.

but i would start with the carburetor and rule it out before i started looking at the timing or the valves.

anyway i can help let me know.

Ray
Wolf Performance  

thanks wolf, that has helped a great deal.
the quad is running but it tends to die when i open it up for a sustained period of time.
then when i restart it (after it has seemingly cooled a bit )it will run not too bad. could this be down to the mix not being just right?
it probably isnt a heat issue although one of the fans is  broken, it only seems to die in 3rd 4th, havent even got into 5th.


the valve i was talking about was not on the carb, but on the "seat" that mounts the carb to the cylinder head its brass i think and i just dont know whether it should have had a "sleeve" on it or to be left bare?

thanks again , your a legend!!

please somebody?!!