Subject: TX750 Oil Filters and "Gorilla Snot"
   Date: Wed, 12 Nov 2003 12:20:22 -0400
   From: "Harry A. Moses" 
     To: 

Hi Roger,

Yes, I am one of the TX750 faithful, and I continue to seek new information about the 
Omni-Phase Wonder. 

Last Thursday evening I attended a local vintage club meeting for the first time. There 
was a chap with grey slicked back hair and a goatee sitting directly across the room from 
me. I hadn’t seen him on any of the group’s summer rides, so I could not place him, yet
something seemed familiar. At the end of the meeting, another person started a conversation 
with this fellow, and as soon as I heard his voice, I knew him… it was Barry Robson, who 
operated the Yamaha dealership in Saint John, NB with his father Millard Robson from the 
late ‘60’s to the early ‘80’s. It had been a good 20 years since I’d last seen him.

We had a lengthy conversation about the TX750, as he had rebuilt many of them in the early 
70’s. He claims the biggest threat to the TX750’s cranks and oil channels was the yellow 
“Gorilla Snot” which the oil filters had been assembled with. He told me he used to find 
this yellow stuff plugging all of the little orifices where oil should go, and it took 
awhile for him to realize what the source was… the darn filters. Later, the filters were 
had there bottoms attached with a silver coloured solder material, and these he thought
should be safe, though not as safe as the adapter and filter setup you had produced for 
several of us a few years ago. So, this should be awarning to any of our TX750 riders out 
there to be careful when buying NOS TX750 oil filters. DO NOT USE ANY NOS OIL FILTERS WITH 
ANY TRACES OF YELLOW GLUE MATERIAL.

Barry was quick to advise me to:

    1.       NOT USE ANY NOS OIL FILTERS WITH ANY TRACES OF YELLOW GLUE MATERIAL. 
             (“Gorilla Snot”)
    2.       add the deep sump,
    3.       add an oil cooler if you can find one,
    4.       use a good 20W-50 motorcycle oil
    5.       use the filter adapter and BMW filter
    6.       find a balancer adjuster kit and install it (not many of these on any shelves 
             out there), OR get the parts off an ’74 engine, and install them on my ’73 so 
             that the balancer chain can be adjusted when necessary.
    7.       check your gap setting on the voltage regulator, as this affects how your 
             battery charge is kept up by the alternator, which in turn affects how well 
             it starts off the button. Don’t blame it all on the starter clutch!

I have had a great summer of memorable Saturday and Sunday rides with both the vintage club, 
and my local cruiser group. We have predominantly traveled two-lane blacktop roads reveling 
in the tremendous scenery of rivers, rolling hills, farmland, and coastal areas of New 
Brunswick and Maine. My total for the year was about 5,500 kms (or 3,400 miles).

The only remaining nuisance/problem with my TX750 is the oil mist that sprays on my pant 
legs and on the bike from the head gasket area. However, Barry Robson reminded me of a fix 
Yamaha made to the rear cylinder studs, because oil would travel from the oil channel up 
through the threads of these studs, and out. He said they essentially dipped them in a 
material which, like Teflon plumber’s tape, would seal the threads, and would prevent oil 
getting past the threads. Sounds like “Loc-Tite” or something similar to me. Bet ’cha my 
’73 has this problem. 

Oh yeah… electronic ignition… I bought a Boyer-Bransden XS650 unit, thinking all things 
being equal it would work. Yes and no… I would have to cut the base to get it the unit to 
fit, and I discovered a problem with the timing advance. In a 1974 motorcycle mechanics 
text, a list of Yamaha details was presented. The advance curve for the XS650 was listed 
as 10 degrees BTDC ~ 39 degrees BTDC, and the advance curve for the TX750 was listed as 
6 degrees BTDC ~ 37 degrees BTDC… obviously they ARE DIFFERENT…. So, I continue to use 
the humble point system. Good luck with your Newtronics unit.

Ta for know,
Harry A. Moses
Lake Utopia, NB
Canada