Quote:
Originally Posted by Munch
Hello GG riders!
I purchased a gas gas ec 250 2006 a few days ago from a family member with a spluttering problem.
Basically it would start first kick every time but the bike would splutter very bad at anything more than 10-20% throttle, I solved this by running a hotter plug (br9) and changing the mixture from 40:1 to 50:1.
Now I am afraid the bike is running lean, I put a fresh plug in and took it for a test ride for approx 5 minutes and the plug was a very light colour, yellow/white colour which I believe means it is lean?
Is there some sort of trick to finding if it is lean? If it is lean how do I go about making it richer?
My settings:
Pilot: 42
Main: 172
Needle: #3
Needle type is "N1EF"
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With todays fuel blends (detergents etc), synthetic oils, and not to mention 5 minutes ride time.. I'm not surprised you have very little colour on the plug. It started out white. If you fear you are lean get a well used plug that's nicely coloured and do a run on it. If you're lean you'll turn whatever colour/carbon is on it white and ashy.
Lean symptoms are as follows
- Hard starting when cold. Needs choke, and needs choke for a long while before continuing to run.
- Once hot you could see weak flat power, hesitation and cold stalling when cracking the throttle open (BOOOWAAAH sound) that drops rev and sounds like its gasping for fuel. Backing the throttle off the engine will want to surge or run on for bit before the revs drop. Pulling the clutch the revs won't drop immediately. At idle the engine will surge, race, and resist settling into a steady idle.
- The engine will run very hot. Pipe may discolour. Coolant may be expelled.
- The throttle response will sound sharp and crisp. If too lean you'll note that it appears the bike makes more noise but doesn't go any harder or faster.
Rich symptoms are smoke, spooge, blubbering wet sound (similar to what you feel when you forget to take the choke off, or ride around too slow and load the engine up with fuel).
A lean setup will typically run like a cut snake for a short period of time and then the power will flatten right out as the engine gets too hot and the symptoms will show.
A rich setup will run poorly in general. Depending on where it is rich it won't take throttle well.. but if transitioning into a leaner area of the jetting it can work through and run ok at certain throttle positions.
After all that, you can be rich in one throttle position, and lean in another. You could be rich across the board, or lean as well. Work methodically and adjust each circuit to seek improvement. If you go lean and pick up symptoms move back the other direction.