Motorcycle Repair: RE: Honda 2007 CRF100F Will Not Start after sitting thru Winter, fiche section, vent line

Question
Hi Bill,
      I bought my son a new 2007 CRF100F dirt bike. He used it only during the summer months and this year it does not start.....I have changed the Spark Plug..........Changed the Oil and Cleaned the Air Filter.....changed the Gas since it sat in the shed from last summer..............It just does not start. I tried to clean the Carburetor...............not sure of the Valve adjustments required..........I few tips to clean and adjust the Carb would really help.Thats what I think.........any suggestion to get it going would be appreciated.
Thanks..............I appreciate it.
Ukesh

Answer
You have to remove the jets and clean them out so you can see light through them. Once the idle mixture jets are clean, adjust the idle mixture screw, which may have a limit cap or be covered with a cap. The mixture screw is set at the factory, but if you can get access to it, a little richening will be helpful.

If the valves are set at .002" and the idle jet is clean, then you should be able to fine tune the mixture adjustment and idle speed.

Bill



Ukesh,

If you stored it with old gas in the float bowl, the idle jet is most likely clogged up. This prevents the engine from idling and makes starting extremely difficult.

http://www.houseofmotorcycles.com/fiche_section_detail.asp?section=525435&catego...   #24   The hole is only about .35mm, but it must be open.

Rotate the engine so the crankshaft flywheel is at the T mark alignment with the crankcase indicator. Check to see if the valves are loose or tight. If loose, adjust the clearance to .002" (.05mm), if tight, turn the engine over ONE turn and check again. Tight valves will decrease compression, making the engine performance very poor.

On the fuel tank, you may need to drain it out and remove the petcock to see if the screen inside the tank has clogged up. Make sure that the fuel cap vent line is open and clear.

http://www.houseofmotorcycles.com/fiche_section_detail.asp?section=525447&catego...   #1

Replace the spark plug with a new one, as the old one is probably fuel fouled by now. Even a new one can become fouled if you keep flooding it with raw gas.

Bill Silver