I have a 06 raptor 350 and recently i added a jet kit and a pipe. Since then my carb has been sounding like it is backfiring. it only does it when it is idling and at low speed cruising. It is jetted like it said and the fuel mixture screw is 3 turns out like the instructions say. I've cleaned it out and put fresh gas back in and Changed the spark plug but still the problem persist, What is causing this?
2007-09-03 07:39:30 · 7 answers · asked by SPEEDY 4 in Cars & Transportation ➔ Motorcycles
Jetting reffers to throttle position and not RPMs so speed is not a factor. Heres what you need to do...
#1 - the pilot jet (sometimes called pilot screw) controls the fuel/air mixture between Idle and 1/4 throttle. Turning the screw IN makes the fuel/air mixture leaner. Turning the screw OUT makes the fuel/air mixture richer. Lean means less gas, rich means more gas.
It sounds like you're describing a rich condition so onto #2
#2 - Every jet is identified by a number and that number relates directly to the size of the opening inside the jet. Again smaller is leaner, larger is richer. When jetting your carb if you find that you need to turn the pilot jet all the way in to improve response then you likely need to switch to a smaller number of screw.
If on the other hand you need to turn it more than 2.5 turns out you likely need a larger numbered screw.
Now that you understand the why turn the screw IN to lean out the mixture a little bit. Don't turn it in too far, a lean condition over a period of time causes engine damage. Turn it in half a turn at time and test for results.
3 turns out is letting too much gas into the carb and its not getting burned. The book probably says that to keep your engine safe since being too lean causes engine damage while too rich usually just makes the engine shut down. Hope that helps.
2007-09-06 20:58:16 · answer #1 · answered by Travel Gal 3 · 0⤊ 0⤋
Atv Backfiring
2016-12-18 06:19:48 · answer #2 · answered by Anonymous · 0⤊ 0⤋
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RE:
Atv is backfiring through carb.?
I have a 06 raptor 350 and recently i added a jet kit and a pipe. Since then my carb has been sounding like it is backfiring. it only does it when it is idling and at low speed cruising. It is jetted like it said and the fuel mixture screw is 3 turns out like the instructions say. I've cleaned...
2015-08-18 23:40:57 · answer #3 · answered by Laurice 1 · 0⤊ 0⤋
There was a recall on earlier Raptors.
They would back fire and blow the carbs off the manifolds.
Check if running with the airbox cover removed fixes the problem.
If it does, turn the mixture screw in a turn and re-install the cover.
Sometimes drilling a few 1" holes in the airbox cover will increase air flow and improve running.
If any modifications are done to the cover, install a K&N air filter with a precharger, or power lid (air box cover).
http://www.powersportrider.com/CGI-BIN/ZCATJPG?catalog=ST0206C
Pick - ATV Catalog
Go to - Index - K & N - Air Box Lid & Filters Precharger
2007-09-03 09:09:35 · answer #4 · answered by guardrailjim 7 · 2⤊ 0⤋
The mixture is running too rich. Have the carbs balanced and then try 2 1/2 turns on the screws.
2007-09-03 09:58:10 · answer #5 · answered by Anonymous · 0⤊ 0⤋
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Sounds like the needle & seat are gummed up. Clean the carb. with 2+2 carb cleaner. That will dissolve all varnish and gum.
2016-04-10 11:48:01 · answer #6 · answered by Anonymous · 0⤊ 0⤋
You mentioned he lapped the valves, but it sounds like the intake valve is not seating properly. This would cause it to backfire through the carb. Have him replace the intake valve and spring and you will probably be good to go. Hope this helps and good luck
2016-03-17 03:00:35 · answer #7 · answered by ? 3 · 0⤊ 0⤋