2018 GP300 not starting / breaking kickstarters
- Thread starter Undertow
- Start date
Hi Neil,
Not really. The engine not idling was really the first symptom I noticed (where in the previous 18 it had always idled perfectly). Then I noticed the surging/hunting after revving the engine and it?s closed throttle returning to idle. Do these symptoms sound like the pilot jet to you?
Not really. The engine not idling was really the first symptom I noticed (where in the previous 18 it had always idled perfectly). Then I noticed the surging/hunting after revving the engine and it?s closed throttle returning to idle. Do these symptoms sound like the pilot jet to you?
If the pilot jet is plugged, the engine tries to idle on the spillover from the needle. To do this the slide stop has to be screwed in almost to the point of coil binding the screw spring. It will change RPM and not really idle. This scenario does not "just happen". It usually results after the bike has been stored for a few months. The gas varnishes over time and plugs the pilot jet. With the pilot jet removed and held up to a light you should see through it clearly. I doubt this is your problem.
I don't expect a 2T to idle well. Temperature changes will affect how it runs. If you are running the bike hard, it is common for the idle to change a bit. The real question is "What's in it for jetting?". The stock N1EF needle is known to be an issue. If you have a 42 pilot jet, the air screw should be about 1.5 to 2 turns open from lightly seated. My bike runs best at 2.5 turns out on a 42 pilot jet.
On deceleration does the bike "Knack"? This is the sound of unburnt fuel igniting in the pipe. It usually means the bike is set up too rich. The problem is that your description so far would make me think your jetting is bit lean. If you were getting a kickback on starting all the time, I'd check the flywheel key as Davehuge suggests.
I don't run a thermostat in my bike so I get more variation in how my bike runs. I also don't change my jetting through the year. It is set up for spring & fall. Thus it runs slightly lean in late fall and the engine gets noticeably crisper. In hot weather it's slightly rich and feels a bit soft.
At this point I'd say you need a better needle.
I don't expect a 2T to idle well. Temperature changes will affect how it runs. If you are running the bike hard, it is common for the idle to change a bit. The real question is "What's in it for jetting?". The stock N1EF needle is known to be an issue. If you have a 42 pilot jet, the air screw should be about 1.5 to 2 turns open from lightly seated. My bike runs best at 2.5 turns out on a 42 pilot jet.
On deceleration does the bike "Knack"? This is the sound of unburnt fuel igniting in the pipe. It usually means the bike is set up too rich. The problem is that your description so far would make me think your jetting is bit lean. If you were getting a kickback on starting all the time, I'd check the flywheel key as Davehuge suggests.
I don't run a thermostat in my bike so I get more variation in how my bike runs. I also don't change my jetting through the year. It is set up for spring & fall. Thus it runs slightly lean in late fall and the engine gets noticeably crisper. In hot weather it's slightly rich and feels a bit soft.
At this point I'd say you need a better needle.
dANbOT
New member
I had something similar happen a few years back on a 2014 ec300 electric start model. After alot of frustration, I found poor connection at the ECU connector which was causing random spark as it was arcing. I'll see if i can find the old video i made. When staring the bike it was a 50/50 chance of either starting normally, or kicking back with a lot of force. I broke several starter ring gears, and 4 or 5 kick start shafts.
Might not have anything at all to do with your issue, but something to look at. It sounds like your bike could be pre-igniting before TDC as mine was.
https://youtu.be/cPBOptQHToE
Might not have anything at all to do with your issue, but something to look at. It sounds like your bike could be pre-igniting before TDC as mine was.
https://youtu.be/cPBOptQHToE
Hi guys,
Found the problem. Pilot jet clogged. You could only just see light coming through it. I bought a new one which you could see was noticeably more open. Bike runs perfectly once again. Not sure how the clogged pilot made her kick-back so bad but should be all good now. Thanks for the help to get to the bottom of this.
Found the problem. Pilot jet clogged. You could only just see light coming through it. I bought a new one which you could see was noticeably more open. Bike runs perfectly once again. Not sure how the clogged pilot made her kick-back so bad but should be all good now. Thanks for the help to get to the bottom of this.
