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This an issue known to KTM, although I don't know if it is known to have occurred on a standard bike.

A particular situation when this can occur is if the Akra - EVO1 exhaust is fitted. Although never specified for the RC8R it does fit and the dealers kept on recommending and selling them for RC8R's. This then means that at high revs the valves start to float and can then actually come free. A missed gear or fitting of a quick shifter will make the issue more likely. In the UK (at least) KTM issued a notice to dealers on the 25/7/2013 to the effect that the “KTM Supersport Exhaust” (Akra - EVO1) if fitted to RC8R 2011 or later models could lead to damage.

So in summary it is a known issue to KTM and more exactly they understand why it happens and at least one of the causes. There were 3 cases in the UK RC8R/EVO1 with this issue that I know of.
 

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Thanks for the reply Zippy.
Coincidently, I have a FMF slip on exhaust and also have a Bazzaz quick shift installed. I'm pretty sure I can recall exactly when the float occurred - a distinctive "pop" from the exhaust shifting from second to third so it is possible I need to time the load sensor and engine kill time a little closer.
Since there is no guaranty this won't happen again, I'd like to find out if anyone has come up with a counter measure. Either increasing valve seat pressure by adding a shim or using a slightly heavier spring? If nothing else i'm thinking of adding a screen to the oil return path to keep the shim in the head?
 

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Discussion Starter · #43 ·
still have my RC8R engine is working fine but I only have 8k miles.

aftermarket exhaust cause valve float?

don't know which akra I have but it's a full size can. I put in custom DB killer it is very restrictive to pass 91db limit at the track
 
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