Question about 2004 Derbi Senda SM 125 4T
When riding my Derbi Senda it works fine in the bottom end but when i get into the top end it starts to drop power and cut out, i have tried everything what i can think of. but my bike does have a derestricted exhaust and a 21mm carb, i have messed around wht the jetting and needle and even tried a sports air filter, the bike has almost everything new, so I don't understand why it is cutting out.
Adjust the mixture screw outwards about half a turn at a time to make it richer it is running too lean at the top end
Posted on Apr 13, 2014
Testimonial: "I have tried adjusting the mixture screw but it has not made any difference."
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Posted on Jan 02, 2017
SOURCE: engine not running
Your carb should have another jet. What you cleaned was the main jet in the center of the carb. There should be another jet called a pilot jet. Often it has a metal plug covering it up so the setting can not be changed at that point. Instead, they want you to change the setting with the pilot air screw. In each case, if you remove the screw, count the number of turns for removal and put the screw back the same number of turns.
The pilot jet controls the idle. It picks up gas from the float bowl then the gas gets metered by the jet and the air screw then passes through a circuit (drilled passageway), in the carb casing and comes out in the center of the carb close to the needle jet. You will need to get the jet and circuit cleaned.
Posted on Jul 08, 2009
The problem is that one of the bulbs has blown or you have a bad earth connection on one of the black wires coming from one of the indicators,clean connections with wet and dry sand paper. Finally check the wattage of the bulbs is correct something like 3-5 watts ,
Posted on Feb 12, 2010
Testimonial: "cheers i will give it ago today many thanks"
SOURCE: I have a 2008 Derbi
Hi, you are correct the overflow pipe on the bottom of the carb allows fuel out of the carb instead of it flowing into the engine, you will have to remove the carb and clean it out, sounds like the float needle valve has become contaminated by old fuel which has been standing in the carb, common on motorcycles which have been stood up for the. Winter etc a varnish or sticky substance may be found, clean this away making sure the carb is scruplesly clean inc jets before rebuilding
Posted on Sep 23, 2011
SOURCE: I still cant start my Derbi...
have you checked how much compression there is , 100psi or above ! no less !!
Posted on Mar 30, 2014
Testimonial: "how can i check it? i dont have anything to check it with."
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