Duane Ausherman wrote:Frog will be along any time now to explain the proper use of a flat hammer for use in tuning a /5.
Haha….I don’t think that Duane will ever let me live this down.
So….here is the story.
Last night, Duane, Adam (good friend/mechanic) and I were still discussing theories about the tuning issues regarding the 1972 R75/5 that I did the frame swap on. In doing so, we all agreed that the right side carburetor very likely has an air leak that is effecting the idle.
So, off to the shop we went.
I did most of the work, while Duane and Adam served up opinions, jokes, laughs, lies and more opinions It was all in good fun and more social than work.
We found that the right carb butterfly was not seating well and plenty of light could be seen around the perimeter when closed. I also removed the shaft to check the O-ring (which was okay). I replaced it anyway, since I had it and was there.
In trying to get the butterfly to seat properly, we noted that it was full of prick marks. We removed it and put it on a glass plate….to discover that it was far from flat. I assume that a past mechanic (not really) must have tried to deform it into sealing with a punch or the like. DUMB.
THAT IS WHEN I TOOK OUT MY FLAT HAMMER. I pulled out a hammer….put the plate on the table of my drill press….and tap tap tap. Of course, that drew lots of laughs and jokes…..and without thinking (much), I replied with “don’t worry, it’s a flat hammer”. The laughs immediately turned to hoots…..and some good heckling was added to the evening.
Long story short, we continued to massage this messed up butterfly to coerce the best fit out of it.
In the end we all agreed that it fit much better than before. Both Adam and Duane agreed that we had improved it to near stock fit and likely were about 90% of normal.
I agree that the part should be replaced, but we had nothing to lose in trying to make it work (except our time).
It was too late to fire up the bike, so I am not sure what the results will be. I am hoping that I can get that carburetor to idle at a normal low rpm. If so, I can balance them and send the bike back to its owner….with the recommendation that it be addressed more carefully in the near future.
Go hammers!
PS-Never do this....with anything but a FLAT hammer
