Author Topic: Snapped bolt CB400f breather cover, what to do?  (Read 567 times)

0 Members and 1 Guest are viewing this topic.

Offline Frogger

  • Full Member
  • *
  • Posts: 21
Snapped bolt CB400f breather cover, what to do?
« on: April 14, 2014, 11:40:42 PM »
Hi, I have recently acquired a '75 CB400f and was going to open her up and have a look at least in the top end (have rudimentarily started it with leaky carbs and seems to be running strong enough) - when undoing the breather cover, found one bolt missing and underneath was the remnants of it being snapped of in the head. Any recommendations on how or if I can extract this. I am limited on tools and mechanical experience.
Many thanks.

Offline LesterPiglet

  • Old Timer
  • ******
  • Posts: 4,045
  • 1977 CB550F2
Re: Snapped bolt CB400f breather cover, what to do?
« Reply #1 on: April 15, 2014, 04:51:10 AM »
It looks to me that there is enough sticking out to grab it with vice grips.
'Then' and 'than' are completely different words and have completely different meanings. Same with 'of' and 'have'. Set and sit. There, their and they're. Draw and drawer. Could care less/couldn't care less. Bought/brought FFS.


Les Ross.            Certified by a Professional

oldbob

  • Guest
Re: Snapped bolt CB400f breather cover, what to do?
« Reply #2 on: April 15, 2014, 11:07:39 AM »
My 400's PO broke off several of the screws in the clutch cover. I had some success with drilling them and then using a screw extractor.

Bob

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,289
Re: Snapped bolt CB400f breather cover, what to do?
« Reply #3 on: April 15, 2014, 11:17:44 AM »
+1 on welding a bolt or nut right to it.   take him a few cold beers.
those screw extractors can really ufk things up if not done properly.
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline dave500

  • Really Old Timer ...
  • *******
  • Posts: 17,200
  • WHAT?no gravy?
Re: Snapped bolt CB400f breather cover, what to do?
« Reply #4 on: April 15, 2014, 01:45:23 PM »
gday Brendan,id try giving it a gentle rap downwards with a hammer after crc soaking for a while,then with a carefully positioned sharp punch or chisel try and drive it in the undo direction,you may find itll start turning then once you have a enough to get a decent grab with vice grips its out,never torque 6mm bolts,just nip them down and be sure any blind holes are dug out and blown clear so the bolt doesent bottom out in them.

Offline Christo

  • Enthusiast
  • **
  • Posts: 105
Re: Snapped bolt CB400f breather cover, what to do?
« Reply #5 on: April 15, 2014, 02:08:52 PM »
Hey Brendan, could you carefully grind a slot in it to accept a flat head screwdriver and then try and unscrew?
74 CB550K