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Discussion Starter · #1 ·
Hi,
Earlier this year I was In here asking about a tapping noise on my 2017 duke 390’s engine. Not long after my engine exploded, all the top end was ruined from the piston head up. Since then I have done my best to fix it and have now started it up for the first time!! However there still are some snags that I would like someone else’s opinion on.
Firstly there is still a tapping sound from the top end, not like the old tapping which was I think piston slap. Could be the cam tensioner, I only tightened it when I was rebuilding the engine and haven’t adjusted it with the bike running. it is very obvious that it is coming from the top end however
Next thing is there is oil coming out of the exhaust, I’m hoping this is just the bike spitting out all the **** from when it blew up initially. Im going to take the exhaust off and try give it a clean inside. There was a slight nick on the piston bore. Im hoping this isn’t letting oil through and below
 

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The tensioner isn't adjustable, the screw is used to retract it until it locks in an open position. When you turn the screw the other way it will suddenly release and then the pressure on the chain is just that of the spring.
Did you measure the clearances and put the correct valve shims in?
Oil may have gone into the spark plug hole or straight into the bore while you had it apart, and that will burn off soon enough.
A damaged bore isn't ideal and could be allowing oil to pass the piston.
Are the cams definitely getting oil now? Did you find a reason for the excessive wear on the cams before it stopped running?
 

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Discussion Starter · #3 ·
thanks for the response - yeah cams were in spec (tightest one was about 0.15 away from being out of spec)
previous owner had little to no oil in the block so the cams were worn down to **** (they all got replaced) i put around 1.6/7L of oil in it and then fired it up so oil levels should be okay
i have a vid of the bike running on my phone but not sure how to upload onto here - if anyone knows best way let me know!
 

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Don't tight the tensioner you could damage the crank bearings or the rod. Check the cam chain for wear instead. After tensioner is released it automatically tights the chain no need for over tighting. Better to hear the ticking. The cam chain won't jump a teeth, even if it's loose.

Sent from my A80Pro using Tapatalk
 

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Don't tight the tensioner you could damage the crank bearings or the rod. Check the cam chain for wear instead. After tensioner is released it automatically tights the chain no need for over tighting. Better to hear the ticking. The cam chain won't jump a teeth, even if it's loose.

Sent from my A80Pro using Tapatalk
Not 100% true, if you don't have the tensioner installed you can easily make it jump teeth.
 

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Discussion Starter · #6 ·
Not 100% true, if you don't have the tensioner installed you can easily make it jump teeth.
i have a manual cam chain adjuster - i bought one in a bid to fix the old issue before the the blew up - when i rebuilt the engine i manually tightened it to what i thought was correct - not sure if it would be worth getting a OEM one and see how that goes, just want that awful sound to stop when i turn it on!
 

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Ok tight it untill you can hear slightely the ticking sound. If you tighten it and still hear the ticking sound then it's not the cam chain.

Sent from my A80Pro using Tapatalk
 

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Hi,
Earlier this year I was In here asking about a tapping noise on my 2017 duke 390’s engine. Not long after my engine exploded, all the top end was ruined from the piston head up. Since then I have done my best to fix it and have now started it up for the first time!! However there still are some snags that I would like someone else’s opinion on.
Firstly there is still a tapping sound from the top end, not like the old tapping which was I think piston slap. Could be the cam tensioner, I only tightened it when I was rebuilding the engine and haven’t adjusted it with the bike running. it is very obvious that it is coming from the top end however
Next thing is there is oil coming out of the exhaust, I’m hoping this is just the bike spitting out all the **** from when it blew up initially. Im going to take the exhaust off and try give it a clean inside. There was a slight nick on the piston bore. Im hoping this isn’t letting oil through and below
OMG! What DID you or didn't that your engine EXPLODED?
 

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Discussion Starter · #10 ·
Hello
little thought, could it be that my top end isnt getting any oil due to foreign objects in the oil pump? i never checked it when i rebuilt the engine. there is no warning for low oil pressure however
 

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If the oil pump is blocked by some foreign object you won't be getting oil anywhere.
More likely if you have used (excessive) liquid gasket, some of it might have blocked a passage up to the top end and reduced or blocked the oil flow up.
If you take off the valve cover and start the engine you will see quick enough if the top end is provided with oil.


Hello
little thought, could it be that my top end isnt getting any oil due to foreign objects in the oil pump? i never checked it when i rebuilt the engine. there is no warning for low oil pressure however
 
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