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Hey all! I’m a relatively new rider (6mo now) and new to this forum as well. I bought my 2016 390 Duke off of a friend with 4300 miles on it.

Been riding with relatively no issues so far minus constant oil changes but as of last Friday (7600 miles on the odo) I had the bike overheat and go into limp mode on me for the first time. Going in stop and go (never left 2nd gear in 90F) for about 15 minutes on the highway. Kept on in limp mode till I made it to where I needed to go (another 4 miles). Started up after 5 hours sitting (temp gauge says engine didn’t cool, was 5 bars below H but felt cold to touch?) but on my way home (55F out at 70+mph highway) it went into limp mode again on the highway after riding for maybe 20 minutes, let it cool, made it home okay. Left it alone for a day, started it up for work and wouldn’t start. Misfired twice on start up but the odd thing is the temp gauge said the engine was 4 bars from H while it was cold.. also says “Coolant Temperature High” it did eventually start and ride fine. Left it alone for another day, turned it on but didn’t actually start it and the gauge says the engine is 3 from H now.
Is this an electrical issue? Is that why it’s not starting? Or did I melt it? I do ride it very very hard. (Lots of track riding at 100mph+ at least twice a week) but it didn’t start limping until the high way stop and go.
Oh! Final note it’s 100% stock minus a K&N air filter.

in other words, I have no idea what to do. I’ve heard of the Spal fan up grade and switching to Engine ice but why is my gauge off and why is it misfiring?
 

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How much $ is a coolant sensor? If not much money I would try replacing that alone and see if there is a change in the temp readout on the dash. Perhaps it has failed and is giving a wrong signal to the ECU, triggering limp mode and mixture problems upon startup.
worth a try. Sorry I am of no help. Others will be
 

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this might be the issue,happened to me once.if there stucks air in coolant system coolant wont circulate,thus leading to overheat even if the fan is working and you have enough amount of coolant.what to do? open the radiator cap,release all the stuck air out.done and done.
52545
 

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The OP has been riding with no issues for a while.
Unless he has been fiddling with the radiator or cap, it is highly unlikely that air gets into the radiator and cooling system.
In the manual, it describes how to renew and bleed the cooling system.
This is not done with the filler cap but the bleed screw on the left side of the radiator.
This is a 6mm thread 10mm head screw that is flattened off on 1 side in order to let the air out.
Perhaps not necessary but do not open the radiator cap on a hot/warm engine.
 

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Yeah my bad sorry,let me correct my post.you need to renew your coolant without any air left inside in order to circulate properly.cheers
 
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