Author Topic: Dowels in Crankcase and Behind Timing Covers  (Read 2175 times)

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5076
  • Karma: 48
Dowels in Crankcase and Behind Timing Covers
« on: 28.05. 2008 04:37 »
Gents:

There are three dowels I belive I am missing, at least I can't find them in the garage (aka, shed).

One of these (67-1236) serves to line the breather duct where the crankcases join. I can't remember ever having this during the first rebuild. It might have been there while I ignored it, then, fallen out some time during the current rebuild (perhaps, at the machine shop). The question is, do I need it? I suppose they put it there for a reason, as in, keeping oil from leaving through the outer breather hole.

The second (27-1589), seems to serve a similar purpose between the outer timing cover and the crankcase, however, the crankcase side, where this would join, is not shouldered, as in the other holes. Does anyone know what specific purpose this dowel serves? Again, do you think I need it?

The third (66-3074) goes between the inner and outer timing covers. Need I repeat the questions?

Any advice, admonition or incantation you can offer whould be appreciated. I identified ths "small" discrepancy just before closing the crankcase. So, now, that waits. I am going to feel truly stupid when or if one of you says, "Ah ha! That's why you spun a rod bearing, Richard." 

Richard

Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online Brian

  • Wise & Enlightened
  • *
  • Join Date: May 2007
  • Posts: 1708
  • Karma: 41
  • Mt Gambier, South Australia.
Re: Dowels in Crankcase and Behind Timing Covers
« Reply #1 on: 29.05. 2008 02:55 »
These dowels help in the alignment of the cases. They are necessary and I would get some and put them in if you are missing any. I cant remember exactly but I think there is only one between the cases, as you describe on the breather passage. Between the cases and the inner cover there should be two, one just above the breather passage and one in the bottom right hand corner. These two are solid. There should also be two between the inner and outer covers, both tube type for the screws to go through. You will be able to see the recess in the holes where they are meant to be but one is above the gen drive sprocket and the other behind. Hope this helps Richard.                  Brian.

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5076
  • Karma: 48
Re: Dowels in Crankcase and Behind Timing Covers
« Reply #2 on: 30.05. 2008 01:07 »
Brian,

Thanks for the reply. Now that you say it, the dowels are clearly necessary for parts alignment, though, I still think the one in the breather duct may be helping to keep oil out of the duct. That is the only one I actually did not have. I think I was lucky to find it at www.domiracer.com.   The case-to-inner-cover dowels were actually in place, but I was confused by the exploded view in the parts book showing them as tubes (see the drawing) rather than solid, as mine are. As for those between the inner and outer covers, those were also in place, but I was too lazy or too forgetful to dig out the cover before writng my last post. And now, I have a bit of egg on the face.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.