Slowly learning about 2 strokes.  Was trying to see if the auto oiler is working after reading the tech rebuild article. The check ball and spring is missing from the upper banjo bolt.  Any suggestions for vendors for these vintage bikes?  Thanks. 

When you say "upper banjo bolt" are you talking about the small line banjo bolt on the oil pump or the banjo bolt at the cylinder? 

Anyway, might be available from Yamaha or search part number on ebay.

DEET would be another source...  probably best to send him the pump and have it gone through.



 

Yes.  Thanks for the tips.  I did look on ebay but no dice

Sorry, been a long day. At the cylinder head.  

No9 & 8
www.partzilla.com/catalog/yamaha/motorcycle/1973/ct3/oil-pump

Glad I asked.  Not sure what "tech rebuild article" you read?  It might be confusing because the pump being rebuilt may have been a twin cylinder engine which has two outlet banjo bolts on the pump.  Your bike only has one banjo bolt and one check valve at the pump. 

The check valve is at the pump NOT the cylinder.  Do not install a check valve ball and spring at the cylinder end of the oil line.

I think I found the "how to" article in the Tech Library you may have read.  Makes it seem easy but it's not.  One thing to notice is the author identifies the pump being rebuilt.  "The pump used in this rebuild is from a 1965 YDS3C Bigbear"

The YDS3 is a twin cylinder engine with two banjo bolts and check valves in the pump!  There is a picture that kind of shows the two banjo holes and the bleed screw hole.  They never clearly show that pump has two banjo check valves but if you re-read now it might be more clear.

 

Again, do not install a check valve ball and spring at the cylinder. 

Yep, that was the article by Makotosun on rebuilding an automatic oiler.  One photo shows 2 springs and check balls which confused my feeble mind. Thanks for the info.  

I wouldn't say you're feeble at all...  The article Mako posted from the YDS parts place is not clear about that point...  and I can say with certainty you're not the first or only person that thought the cylinder end had a check valve too after seeing a "how to" on a twin pump. 

Don't ask me how I know. 

Anyway, if you're concerned about pump sending it to DEET for a rebuild is a good way to get piece of mind.