Topic: Cylinder head dome nuts

[malcolmgb]

400f
Fitted cylinder head last night, checked it again today before continuing with rebuild and one of the chrome dome nuts striipped it's threads.
Torqued down to 14.5 ft/lbs
Is this a known problem? should I now strip down again and buy new replacement nuts?

[Tim.]

14.5 sounds high - is that the spec in your manual?

[bryanj]

Just replace the suspect nut(s) and check the stud threads. As i remember it there are copper sealing washers under some of the nuts but cant remember which ones, or indeed be sure i am right

[supersport_CB400F]

I'd back them off in the proper order get new ones and do it again ...if the studs are not good let me know I have some spare ones knocking around you can have if I have the correct size.

Dave

[malcolmgb]

thanks Dave, the stud looked fine, just the threads pulled straight out on one nut, I put another standard nut on straight away to keep the tension even on the whole of the head, my worry is now that other nuts may be very weak too. I have ordered a complete new set of 8.
Do you think it will be ok to back them all off again and then retighten with new nuts and not replace head gasket etc?
Since it was not a total rebuild, just a reassembly of the top end as I received it, I wanted to get it up and running to find out what it sounded like, run it until Winter then remedy anything found. Reluctant to spend too much at this stage.

[supersport_CB400F]

Malc if you never run the engine and the metal expanded I'd use the gasket again, some guy I knew used his old gasket and never had a problem but it was the original Honda graphite type one lucky sod!

Dave

[malcolmgb]

ok Dave, not sure what you meant "and the metal expanded" but just tightened head down & went no further, the cylinder base gasket was smeared with grease to help seal and seat. The head gasket used was in a new 'Genuine Honda' kit and came with bike, I seem to remember it was very pliable and black like graphite.

[supersport_CB400F]

I meant the engine had not run and got hot Malc …..You should have no probs torque it then leave it for a while then do it again and it’s happy days.

Dave

[malcolmgb]

ok got my new cyl head nuts today, they are very different to the orignals I have, they are plain steel the originals were chrome plated, also have a large washer type base. Were my originals the correct one's? the metal certainly seemed quite brittle which maybe why they stripped threads.

[supersport_CB400F]

Your new nuts look the same as my original nuts......god if ghouliie gets on this one I'm going to fall off my chair .......those new ones are the nuts Malc sorry but I'm smiling big time I'll flash up a photo in the morning sorry mate use them with the copper washers 

[malcolmgb]

phew!!! my nuts look like everyone else's now 
I tried to be carefull how I worded my message early on to stop any double entendre.
Thanks Dave

[supersport_CB400F]

phew!!! my nuts look like everyone else's now 
I tried to be carefull how I worded my message early on to stop any double entendre.
Thanks Dave

Malc I prefer the word fastener, at least I can keep a straight face while I’m typing ….sorry I’m just a scoucer with a sick sense of humour