Topic: 1975 Cb400f stripped valve cover bolts

[mickvain]

So have had a slight weep since I purchased the bike 2 months ago at the valve cover gasket. Slight means very slight. I can see a bit of oil at the upper most fin but over the last 500 miles no change in oil level. (Meaning negligible to the marks on the oil stick.) decided to cahange oil again yesterday after syncing carbs again because I am anal and found the source of the weep. Touched a bolt a driver front left on valve cover and it was loose and again and driver back right and it was loose. Let bike sit for a couple of days as other projects arose and went to work on it. Backed the bolts out by hand and both had aluminum on them. Figured PO tried to fix the weep by tightening them down beyond spec and stripped the valve cover.
I will take pictures in the next few days. Figure there area few options. Chase the threads to the original bolt size. Go up one size. Ignore it. But seriously, it seems that the are closed point so chasing them would not be a problem. I'll get picture up soon. It is summer and riding time. Also I am four pints in and the boss lady is staring angrily at me....

[MoMo]

next size up is not an option,  either chase the threads or helicoil//insert.  Or..........................................leave it as is and enjoy riding...Larry

[Tim2005]

Helicoil them, and fit a new gasket too.

[flatlander]

what tim says.
leaving as is... i wouldn't do that for a long time, especially as you found two that are loose and there may be more. the valve cover contains the upper half of the cam shaft bearings and also holds pressure on the cam followers against the valve springs. depending on which bolts are loose and how many of them, it may cause damage.

and have another two pints!

[mrbreeze]

I have a spare early 750 head that I got with some parts bikes. Upon examination I found someone had installed a Helicoil in one of the valve cover bolt holes. This hole was drilled all the way through into an intake port. Now I know that when the valve cover is installed....this hole will be covered by the bolt but I still wouldn't run it this way. I know this could be properly repaired but my point is.......If you go to install a helicoil...don't drill too deep.

[NobleHops]

<whispering> TimeSert

[jonda500]

+1 for HELICOIL!
John

[mickvain]

I'm guessing the thread pitch and size is in the parts fiche. I could ignore it as after another 100 miles today the weep is the same as it was before discovering the issue, but proactive never hurt right? Helicoil it is!

[MoMo]

6 x 1.0