ER5 hole in engine

[proximity]

Anyone know what this is for, some kind of hole which smokes sometimes.
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2004 Aprilia Tuono

[instigator]

Well, thats a new one

Don't think mine has that and I don#t think yours should! Of course, I'm not sure..

[iCraig]

Its the spark plug drain hole.

All the EX500 engines (whether in the GPZ, ER-5, or KLE) have them, and I'd be pretty supprised if it didn't. Basically its there to drain away any water sat on the top of the engine.

[wilberforce]

[numark1]

Looks to me like speed holes. Will probably increase your bhp by 10 and add an extra 15 mph.

[conpants]

its a pencil sharpener

for instance:-

you have commuted to your office and have a report to file before 12:00, but that HB pencil is blunt and as usual the office pencil sharpener is missing and you dont want to go into another department to borrow theres, as you made a fool of yourself at the office party. therefore you goto your er-5 to sharpen your pencil and everything is fine

clever planning by kawasaki really

[stinkwheel]

Yep, it is a drain hole for the recess the plug sits in. Ordinarily nothing should come out of here. If you are getting a lot of steam coming out it is likley that one of the two coolant pipes that go down through the top of the rocker cover is leaking. Water could get in there if you have been riding in very heavy rain but it is unlikley.

This is very common and is invariably caused by someone removing the rocker cover to check the vlave clearances at a service then failing to fit new o-rings (at 50p each) on the ends of the two pipes when they refit them.

They are easily replaced if this is a problem but you will have to drain the coolant to do it, after that it is a case of tank off, undo the two screws that hold the pipes in, pull the pipes out (up), replace the o-rings then reassemble and refill with coolant.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[proximity]

Ah that would make sense. I think it is leaking because it keeps drinking all the coolant.
Its my mates bike he just got yesterday, we thought it was some kind of dodgy mod.
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2004 Aprilia Tuono

[tony532]

i bit like me thinking the drain hole on my exhaust was there because someone had drilled a hole in it to make it sound throatier

[Zoffo]