PROBLEMS WITH A SUNL SLD-146 DIRT BIKE

[amyxcycleshop]

I AM HAVING PROBLEMS WITH A SUNL DIRT BIKE. THE PERSON BROUGHT IT TO ME SAYING IT WAS RUNNING AND STARTED GETTING HARD TO START. THERE IS WHAT LOOKED LIKE SEALANT OF SOME SORT IN THE CARB SO WE CLEANED IT. I ALSO LOOKED AT VAVLE LASH AND FOUND THEY WERE TOO TIGHT NOW SET AT .005 INTAKE AND .004 EXHAUST BUT IT STILL BACKFIRES LIKE IT IS LEAN, TRIED ADJUSTING AIR FUEL SCREW AND GOT SOME BETTER BUT NOT RIGHT YET SOME TIMES IT SEEMS TO RUN OK AND OTHERS WONT HARDLY REV UP. IT ALSO TRYS TO BACKFIRE THRU CARB. ANY SUGGESTIONS WOULD BE GREAT. THANKS

[waynev]

Some good reading here about backfiring thru carb or exhaust and some possible things to look for.

http://www.mikuni.com/fs-tuning_guide.html

You might also want to check the spacer between the carb and manifold, they are usually plastic and maybe it has cracked which might explain the stuff in the carb and possibly an air leak which would lean it out causing the backfires, also being lean it would be harder to start.

[amyxcycleshop]

THANKS THAT IS GOOD READING AND ALREADY CHECKED THE SPACER AND TIMING. CAN'T FIND ANY AIR SUCKING ON THE CARB, INTAKE SPACER OR INTAKE TUBE.

[waynev]

Did you have the carb totally apart to make sure there is no crud in the pilot and main jets or a blocked passage?

[phil]

i know this sounds terrible, but unless your trying to get more performance and since you most likely are working on the clock, i would just replace the whole carb. the price is cheap and assuming you have checked everything like air leaks, compression, gas etc. its all thats left, when you take in your wages i think the owner would come out cheaper, and you keep from pulling out your hair :lol:

[david3921]

I don't know about this bike but .005 and .004 still seems too tight. Do you have a manual that lists the gaps?

EDIT; I searched for the valve gap for a Honda 150 and it's .004 for both so you are correct with yours. I was thinking millimeters rather than inches. Sorry.