Engine Knocking Upon Hard Deceleration
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Engine Knocking Upon Hard Deceleration
Well I took out the '88 KDX for the first time after break in of the new top end.
Everything ran great with the exception that when I would decelerate hard, I got a knocking / rapping noise from the engine. This wouldn't happen every time - mostly when I was in 4th or 5th at high speed and then decelerating or coming down a hill and downshifting.
I checked the rod for any up and down play when I had the head off and there didn't seem to be any.
Has anyone experience this before? If so, what did you find out was the reason?
Really appreciate any input.
Everything ran great with the exception that when I would decelerate hard, I got a knocking / rapping noise from the engine. This wouldn't happen every time - mostly when I was in 4th or 5th at high speed and then decelerating or coming down a hill and downshifting.
I checked the rod for any up and down play when I had the head off and there didn't seem to be any.
Has anyone experience this before? If so, what did you find out was the reason?
Really appreciate any input.
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Re: Engine Knocking Upon Hard Deceleration
Did you have the clutch pulled in?
Which octane of gasoline do you run?
Which octane of gasoline do you run?
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Re: Engine Knocking Upon Hard Deceleration
Only pulled the clutch in to shift gears but cant remember if i did that every time.
Used rec gas with 40:1 amsoil interceptor
Used rec gas with 40:1 amsoil interceptor
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Re: Engine Knocking Upon Hard Deceleration
rec gas??
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Re: Engine Knocking Upon Hard Deceleration
Rec gas= recreational gas (non-ethanol)
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Re: Engine Knocking Upon Hard Deceleration
What is the octane??
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Re: Engine Knocking Upon Hard Deceleration
90 octane.
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Re: Engine Knocking Upon Hard Deceleration
Could it be chain slap? Check the tension and condition of the sliders.
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Re: Engine Knocking Upon Hard Deceleration
That's not a lot of octane. Make sure it is not detonation.
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Re: Engine Knocking Upon Hard Deceleration
Not chain slap.
Sounds like detonation. Any way i can determine if it is?
If 90 octane isn't enough, what else can i get?
Sounds like detonation. Any way i can determine if it is?
If 90 octane isn't enough, what else can i get?
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Re: Engine Knocking Upon Hard Deceleration
Do you not have higher octane in your area? Can you go to a marine gas station? I hear you all have a lake or two in Michigan. :-) A buddy here in AL (member here, treelimb) gets 93 octane non-ethanol at a marina.
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Re: Engine Knocking Upon Hard Deceleration
Yeah - Ill get some racing fuel and see if that helps.
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Re: Engine Knocking Upon Hard Deceleration
Well I mixed 50% 90 octane rec gas and 50% 110 octane race gas to get 100 octane. I only get slight knocking for about the first minute of gentling riding it around after it's warmed up. No knocking on hard deceleration anymore however my last ride was on a slow single track and not a big open loop like before.