Why does my engine sometimes "diesel" after I turn it off?
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Grand HDF Member
Joined: Jul 2017
Posts: 4,698
Likes: 5,297
From: Behind you, making faces
Why does my engine sometimes "diesel" after I turn it off?
I recently re-jetted my carb with the CV Performance kit. It pulls WAY harder now and just generally feels much better, so this is a minor issue.
Since I re-jetted, the bike will sometimes "diesel" or "run on" for a couple of seconds after I hit the kill switch.
Any ideas what would cause this?
Since I re-jetted, the bike will sometimes "diesel" or "run on" for a couple of seconds after I hit the kill switch.
Any ideas what would cause this?
Grand HDF Member
Joined: Apr 2007
Posts: 3,727
Likes: 3,072
From: Brighton, MI
I'm thinking lean... a hot spot in the combustion chamber is making it run on after ignition is turned off.
If this condition is new since the rejet, go one size larger. Jets of the same size from different manufacturer's can be slightly different in the amount of fuel they flow.
But as TH mentions, try a different fuel source if you have been getting it from same location. YD
If this condition is new since the rejet, go one size larger. Jets of the same size from different manufacturer's can be slightly different in the amount of fuel they flow.
But as TH mentions, try a different fuel source if you have been getting it from same location. YD
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
As YD points out, you have a hot-spot in the combustion chamber, which can typically be the spark plug itself, or the exhaust valve. Not good! As well as the suggestions above check your ignition timing, but solve it pdq.
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Grand HDF Member
Joined: Jul 2017
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From: Behind you, making faces
I forgot this detail when I posted..... it only does this about once every 5-6 times I shut it off, so it's not a consistent thing.
As for gas, I only run 87 octane, but it's always ethanol-free.
As for gas, I only run 87 octane, but it's always ethanol-free.
Road Warrior
Joined: Apr 2018
Posts: 1,347
Likes: 820
From: Moneta, Virginia
I had the same issue after jetting with CVP jets/needle/emulsion tube.
Higher octane gas, 89 no ethanol stopped mine. I also turned the idle jet screw another 1/8 turn to the right.
Its probably running a bit rich, causing a bit of carbon buildup on the piston top. You can also run a bit of seafoam gas treatment through it.
Higher octane gas, 89 no ethanol stopped mine. I also turned the idle jet screw another 1/8 turn to the right.
Its probably running a bit rich, causing a bit of carbon buildup on the piston top. You can also run a bit of seafoam gas treatment through it.
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Thread Starter
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Grand HDF Member
Joined: Jul 2017
Posts: 4,698
Likes: 5,297
From: Behind you, making faces
I had the same issue after jetting with CVP jets/needle/emulsion tube.
Higher octane gas, 89 no ethanol stopped mine. I also turned the idle jet screw another 1/8 turn to the right.
Its probably running a bit rich, causing a bit of carbon buildup on the piston top. You can also run a bit of seafoam gas treatment through it.
Higher octane gas, 89 no ethanol stopped mine. I also turned the idle jet screw another 1/8 turn to the right.
Its probably running a bit rich, causing a bit of carbon buildup on the piston top. You can also run a bit of seafoam gas treatment through it.
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Road Warrior
Joined: Apr 2018
Posts: 1,347
Likes: 820
From: Moneta, Virginia
I live on a lake, so no-ethanol gas is available everywhere, when traveling not so much. When 10% ethanolI is all thats available, I run premium 92 or 93... that works too.
