Topic: CB750 Oil Filter Mating Surface Damage Help

[MikeTwo]

Hi guys! Changing oil on my newly aquired CB750, and I noticed the nicks on the mating surface where the filter housing is mounted to the engine. What a nice surprise! No idea what had happened to it. The PO used some sort of a light red sealant on the oring. What do you think I should do now to prevent oil from leaking once I put everything together? Some special sealant? Repair the surface with something? Do nothing and just oil the oring?
Thank a lot for your help!
Michael

[rotortiller]

Personally I'd repair the surface by a resurfacing method. Others might suggest JB Weld and sandpaper to smooth the gouges

Glue abrasive paper to a flat circular device with a hole in the center the size of the filter housing.

[ekpent]

  Mercy is that a silver engine under all that gunk or a black F engine bike ?  Cal's suggestion would be the easiest do it yourselfer fix  Hopefully no more surprises !

[MauiK3]

Since it may be difficult to sand a repair flat, maybe a length of carefully sawn and flattened PVC pipe with sandpaper glued to it would help.

[rotortiller]

However you do it it will require sanding so plug the oil holes on the engine to prevent debris entering. MauiK3 has the right idea but use a centering device on the pipe to make it easy.

[MikeTwo]

ekpent yeah it's a black F3 with gunk on it too
Thanks a lot to all of you guy for your input.
It seems to be a fun repair. I will definitely plug the oil holes. Still thinking whether to do JB Weld or resurfacing.. In both cases I need some sort of circular sanding device

[MikeTwo]

Thank you calj737

[PeWe]

PO might have had problem to remove a too hard tigtened bolt? Going in the hard way...

[DaveBarbier]

If you can get a file to lay flat on it I would file the high spots and JB weld up the low spots.

[Don R]

 Don't make it harder than it is. a pipe tool sounds unwieldy and won't provide a wide surface for the sandpaper. Just use fine emery cloth or wet/dry sandpaper on a small flat rigid sanding block. Go easy and pay attention to the sanding marks, you only want to level it not make a new surface.

[DaveBarbier]

If you can get a file to lay flat on it I would file the high spots and JB weld up the low spots.

The only reason I’d shy away from a file is that the steel is harder than the ally and will remove ally easily. Sand paper will take much more force to remove ally than JBW. You’d sand the oxide layer long before you ever gouged the ally base material.

Agreed, but I’d use the file precisely because I would want to get it done quicker, haha. Laying a file flat against aluminum would be safer than going at an angle but I see your point. I like the file also because it’s flat and will be easy to pick up the same plane as the existing surface. But I suppose a sanding block would work too.

Many ways to do this. Main thing is don’t gouge the good part.

[rotortiller]

I would do a little investigation with a ruler and see what I could come up with and modify into a surface refinishing tool.

[HondaMan]

The F2/3 had a "cooler" of a finned plate that was mounted between the filter housing (and filter) and the engine, ostensibly to "cool the oil" (it didn't, really...). The extra-long oil filter bolt then made the whole thing really finnicky to try to reassemble: the PO maybe got mad and hit it with a wrench in frustration? (I'd never do that... ).   

But, you can probably use this to your advantage. If you have the cooler plate (or if I have one around here) you can get some of that sticky-back sandpaper that goes on those surface-sander power tools at Ace Hardware, stick some to the back of the cooler plate, then install the cooler plate using the oil filter bolt to align it, and spin it back-and-forth for a perfectly flat sanded surface. If the gouges are too deep for that, I'd go the thin JB Weld route (with super-cleaning first) and then sand IT down to fit.

They don't call me "shade tree wrench" for nuthin'... 

[754]

Cut a donut out of plywood  glue the paper on.. easy..
 I would use JB or Devcon and knock the bulk of it off with a  file.. carefully.
 Then the donutsander..

[Tracksnblades1]

A big flat washer, 2" ID?  ,   might help keep it flat.
Maybe tack welded to the pipe to form a handle.