Hey there


It seems everytime i hit a jump and am in the air my ds backfires...what could be causing this and how could i fix it?


thanks
Rob

 

Does it pop when you let off the gas and deaccelerate? It could be running lean, try adjusting your fuel mixture screw.

 

Is it a 2000 model? i think i remember somthing about a problem in the carburator of that model year, something to do with jumping, dont realy recall what...... just thowing out idea's.....
later

 

Yes the 2000 models I believe didn't have a splash guard in the float bowl and bog on jumps. Mine BOGS in mid air when i hit the throttle for position control on jumps.... It gets annoying, so I will get a splash guard soon...... I don't believe this would cause a POP though..... But it's something to check first.

 

Float bowl height to be .39 +/- .02 when mearsured inline with mainjet housing.
Splash guard a must.
Fuel screw turned out 3 to 4 turns. Based on your setup.
If 4 turns out and still pops , install a 47.5 or 50 pilot jet
I just remembered - 2000 carbs only had a 40 pilot
2001 and up have a 45. If you have a open airbox and slip-on pipe , you may be too lean on bottom.

 

really? mines a 2000 and i jump mine alot an have no problems like that

 

my ds is an 02 baja...where is the fuel mixture screw?...it does only pop when i jump and let off the gas as far as i can tell.


thanks
rob

 

if air is allowed to be drawn into header pipe you could get a pop on deceleration. this could happen if any of the 3 header gaskets are not sealing.

 

hmm. that could be it...i havent yet sealed my trinity head pipe to the rest of the pipe.
can i do this withput removing any of the pipe? if so what kind of sealer should i use?


thanks for the help
Rob

 

I was thinking of a stock headpipe. There are two gaskets at the head and a gasket at the right side U shaped removable head pipe. I think to get a pop from air it would have to enter close to the head where the most heat is. Way back at the headpipe to mid or tail pipe connection probably wouldn't be hot enough to cause a pop. Make sure the seal is good at the head.

if you have a 2000 DS the pilot circuit will be too lean with a good pipe - adjust pilot screw and/or increase pilot jet.