EXUP Valve missing a bolt

[teecee90]

EXUP started squeaking today so I decided to strip and lube it. I've only had the bike 7 months so this is the first time for me...!


Anyway, everything came out fine but it has obviously been a problem for someone in the past. On first look it seemed like one of the bolts had been replaced with a stud and nut. After dismantling is was clear that the stud was just welded to the cover plate and doesn't actually go into the exhaust (see photos below). The original sheared bolt is still in the exhaust.


The stud was obviously welded to the cover plate as an easier option to ensure there is something to fix the cable bracket to without drilling and tapping the exhaust. I've cleaned and lubed the valve and everything seems to work okay with no more squeaking. Question is, is leaving it as it is with effectively only 2 bolts holding the EXUP in place likely to cause any problems or should I stop worrying and leave well alone. I obviously don't want to attempt to drill and tap it if not necessary.

[sadlonelygit]

don't go tonto overtightening the bolts, just nip them up.
i'd be more concerned about the bent exup valve :evil . looks that way from the picture, easy to fix if you're not an animal.

[teecee90]

Didn't really check the valve for true. Looked okay and turned freely when refitted, apart from a slight tight spot in the fully open position. You've got me worried now though. May take it out again and re-check it.

[teecee90]

So, 8 months later I have just removed the EXUP valve for cleaning a re-lubing and sure enough, the valve was bent. A little time with a drill and a dial gauge and it's now nice and straight and moving much more freely. Next time I do it I will probably take the pipes off and get the broken bolt drilled and tapped. You can't rush these things.

[robbo]

There is a procedure known as spark erosion, whereby studs and broken thread taps etc can be removed without damaging the thread. It might be worth seeing if there's a specialist in your area when you decide to get it done.

[Megawatt]

I removed a broken Exup valve stud last week. Easy job if you drill broken stud with small diameter  Cobalt tipped drills. Work up to 4.5 mm, then tap out the remaining thread with a tapered tap.

[sadlonelygit]

bike on centrestand, makita battery drill and some very decent drill bits and plenty of patience..............and coolant...............and a bit more patience