I just had a valve cover bolt drop out!! Covered me, and the bike with a considerable amount of oil. Managed to nurse it home..... The casting that the bolt threads into is broken off. It had been repaired by the PO but of course this info was not passed on to me. I assume that I will have to replace the head unless I find a wizard with a TIG welder. Any suggestions?
"The casting that the bolt threads into is broken off."
The proper fix is to remove the cylinder head, weld up a new Aluminum structure where the original was, then drill and tap the new hole. The job is involved but not difficult for an experienced mechanic, Aluminum welder and machinist. Awesome if that's all the same person!! The cost, if you do the work yourself will be the least. If you have to pay someone else to do it will be lots more -but- you'll have a cylinder head whose valves/guides/seals/etc you know are good.
The problem has a solution, albeit requiring finding the right set of skills.
The head will have to be removed, then locate someone that has the skill level to weld up aluminum as in this case the head will have to be preheated to 400F prior to welding to eliminate post weld cracking. Then drill the head for the installation of a thread saver, Time-sert or Helicoil, I prefer Time-sert because the transition from thread to thread is rounded as opposed to the straight cut of the Helicoil, however, in this application (low tension) either one will work well. I suggest you check with the race or engine building shops in our area for guidance.
The above is very common repair for all aluminum heads. Many years ago I had a Saab Turbo head repaired with a crack in the valve seat area that went into the water jacket.....it was repaired like new and had the car for 5 more years.
There is another product commonly used in the Chemial Industry to repair pumps, the name is Belzona and it is an epoxy type product, very hard, machineable and easy to apply. There are various other products along the same line.
On the other hand, if you find the issue too cumbersome a second hand head will work well after it has been checked out and the valves lapped.
Good luck and keep us posted.
Member #312
06 Suzuki Burgman 650 "state of flux"
79 CBX
I think I've decided to put a band aid repair, JB Weld or something, to hold the bolt in place and take it up to Heid's in Johnsburg NY. I'm not confident about removing the head myself so I'll have them pull it and hope that we can find a welder and machinist to fix the problem. I'm sure the "mechanic" that did the bolts over torqued them as I was unable to take off the bolts, on the left side, using a 40 torx in a screwdriver. I have to get a 1/4" drive torx set for my torque wrench......