My 73 Yamaha TX750 Rebuild.... - Page 4

Motoduc1 · 01-20-2010, 06:51 AM

This might be just folklore, but I once heard that Yamaha actually dispatched a squadron of technicians from Japan to the U.S. just to go around the country and repair TX 750 models. If that story isn't true...it oughtta be!

chiefrider · 01-20-2010, 11:00 AM

I worked in a Yamaha shop in 1973.

When new, the TX750 was a very nice motorcycle. We had a demonstrator, and I rode it alot. Smooth and torquey, with a very nice seat. I thought it was nice looking, too.

The 1973's did have a defect. The crankcase was porus in the area of the timing cavity, so oil would seep in & destroy the points. Yamaha had a recall on these, and were SWAPPING CASES on every one they could get back.

With this recall, their reputation was ruined. Yamaha had a tough time selling the 1974 TX750s, even though the defect was fixed.

I also heard that they would froth the oil in extended high-speed runs, and blow up. I've never seen one do this, but my sample was quite small.

Tom in Salem

concours · 03-28-2010, 11:56 AM

besides tobyfolwick? I'm really looking for the original handlebar bend.. or a description of such.

concours · 06-29-2010, 06:34 PM

Here it is as dragged home:

And then after being made roadworthy.. paint to come next winter

s10rat · 06-29-2010, 08:52 PM

looks nice beside the goofy looking handlebars....

ken_the_carp · 06-30-2010, 02:33 PM

I also worked at a Yamaha dealer when the TX750 was introduced, it was Yamaha's flagship, glorious in it's original metallic gold. The one sitting in our showroom came with a large box of engine parts to be installed before being sold.

The omi-phase harmonic balancer had no provision for balancer chain adjustment, a kit was provided with an eccentric shaft and locking system.
After about 3000 miles the weights started wearing the sides of the cases and we tried to remedy this by added 4 small radial bearing.

The main oil gallery was behind the points, oil constantly leaked into the points compartment, we changed the seals several times. Yamaha sent us a new style labyrinth seal, didn't stop the oil, eventually they suggested that we drill a small hole in the case to prevent accumulation fouling the points.

The engine had double cases (cosmetic covers to hide the functional engine cases). An exhaust crossover was part of the cylinder head needlessly the engine ran very hot, the oil temp was at the upper limits of normal motor oil (not sure I think about 270 deg.F). Yamaha added a sump extension. Oil capacity was close to 5 quarts.

There were some strange electrical issues, a contact was imbedded in the rear brake shoes to light a brake wear indicator on the dash. There was talk of this current "bleeding" back into the electrical system and engaging the starter, this could happen at any time/speed. I did see a TX750 with the crankshaft protruding out of the front of the engine.

Sorry, I'm not trying to put the bike down, just an old fart who thought they were pretty cool just brought to market too soon.

I remember holding one WOT going down a grade, the speedo was reading 128mph.

Ken

concours · 06-30-2010, 07:10 PM

Quote:

Originally Posted by ken_the_carp

I also worked at a Yamaha dealer when the TX750 was introduced, it was Yamaha's flagship, glorious in it's original metallic gold. The one sitting in our showroom came with a large box of engine parts to be installed before being sold.

The omi-phase harmonic balancer had no provision for balancer chain adjustment, a kit was provided with an eccentric shaft and locking system.
After about 3000 miles the weights started wearing the sides of the cases and we tried to remedy this by added 4 small radial bearing.

The main oil gallery was behind the points, oil constantly leaked into the points compartment, we changed the seals several times. Yamaha sent us a new style labyrinth seal, didn't stop the oil, eventually they suggested that we drill a small hole in the case to prevent accumulation fouling the points.

The engine had double cases (cosmetic covers to hide the functional engine cases). An exhaust crossover was part of the cylinder head needlessly the engine ran very hot, the oil temp was at the upper limits of normal motor oil (not sure I think about 270 deg.F). Yamaha added a sump extension. Oil capacity was close to 5 quarts.

There were some strange electrical issues, a contact was imbedded in the rear brake shoes to light a brake wear indicator on the dash. There was talk of this current "bleeding" back into the electrical system and engaging the starter, this could happen at any time/speed. I did see a TX750 with the crankshaft protruding out of the front of the engine.

Sorry, I'm not trying to put the bike down, just an old fart who thought they were pretty cool just brought to market too soon.

I remember holding one WOT going down a grade, the speedo was reading 128mph.

Ken

lol, and this 16YO stunt pilot held that bastid WFO on I-495 for miles as well.. I remember 120 indicated.

Richy · 07-01-2010, 04:27 AM

I bought one new, Yamaha left me hanging. I've had a lot of new bikes since then, no Yamahas.

I really like that bike too, it ran and rode well.

concours · 09-11-2011, 05:17 PM

Quote:

Originally Posted by concours

Here it is as dragged home:

And then after being made roadworthy.. paint to come next winter

And as she stands today...

zoo mob · 09-11-2011, 05:28 PM

Great work! Though I'm scared to get involved with one of those, I sure like the way they look and would love to take one for a ride.

NHNRS · 09-11-2011, 06:32 PM

I think I saw your bike today in North Brookfield. If that was it, very nice work!

concours · 09-12-2011, 07:07 AM

Quote:

Originally Posted by NHNRS

I think I saw your bike today in North Brookfield. If that was it, very nice work!

Thanks, It was there. First outing. Rescued at the Bettencourt auction. Didn't see another one, LOL

Sniper X · 09-12-2011, 08:14 AM

Very nice indeed. I loved the way Yamaha painte dthe bikes in the 70s. I worked for a local dealer when they were new, in the mid 1970s until about 1978. I loved the Yamaha XS650 and the TX series and until everyone at the shop ragged on the TX750, I thought I wanted one. But I had a Daytona RD400F and since it was faster, and so sexy looking, I never got a TX750.....Beautiful work and hope it lasts forever. I hear riden as they should be they can be quite reliable.

concours · 09-12-2011, 04:33 PM

Quote:

Originally Posted by NHNRS

I think I saw your bike today in North Brookfield. If that was it, very nice work!

a few pics from www.rice-o-rama.com
here:
http://s1040.photobucket.com/albums/...O-Rama%202011/

concours · 09-12-2011, 04:36 PM

Quote:

Originally Posted by Sniper X

Very nice indeed. I loved the way Yamaha painte dthe bikes in the 70s. I worked for a local dealer when they were new, in the mid 1970s until about 1978. I loved the Yamaha XS650 and the TX series and until everyone at the shop ragged on the TX750, I thought I wanted one. But I had a Daytona RD400F and since it was faster, and so sexy looking, I never got a TX750.....Beautiful work and hope it lasts forever. I hear riden as they should be they can be quite reliable.

We rode the slab for 60 miles in the morning because we were in a hurry... 75-80mph, no worries, sounded, felt great. I had dropped two teeth on the rear sprocket and up one on the front for longer legs. The Amsoil 20-50 makes the clutch a bit grabby, but the engine protection, it's a minor inconvenience.

01-20-2010, 11:00 AM	#47
chiefrider Chrome won't get you home Joined: Nov 2004 Location: The lovely Willamette Valley Oddometer: 1,916	I worked in a Yamaha shop in 1973. When new, the TX750 was a very nice motorcycle. We had a demonstrator, and I rode it alot. Smooth and torquey, with a very nice seat. I thought it was nice looking, too. The 1973's did have a defect. The crankcase was porus in the area of the timing cavity, so oil would seep in & destroy the points. Yamaha had a recall on these, and were SWAPPING CASES on every one they could get back. With this recall, their reputation was ruined. Yamaha had a tough time selling the 1974 TX750s, even though the defect was fixed. I also heard that they would froth the oil in extended high-speed runs, and blow up. I've never seen one do this, but my sample was quite small. Tom in Salem __________________ I have found that all ugly things are made by those who strive to make something beautiful, and that all beautiful things are made by those who strive to make something useful. --Oscar Wilde

03-28-2010, 11:56 AM	#48
concours WFO for 41 years Joined: Dec 2008 Location: Kensington, NH USA Oddometer: 3,995	TX750 forum or page besides tobyfolwick? I'm really looking for the original handlebar bend.. or a description of such. __________________ Too much is just barely enough..... 2007 Tiger 1050 2005 Royal Star Tour DeLuxe 1973 Yamaha TX750 1974 Norton 850 Commando Roadster

06-29-2010, 06:34 PM	#49
concours WFO for 41 years Joined: Dec 2008 Location: Kensington, NH USA Oddometer: 3,995	Here it is as dragged home: And then after being made roadworthy.. paint to come next winter __________________ Too much is just barely enough..... 2007 Tiger 1050 2005 Royal Star Tour DeLuxe 1973 Yamaha TX750 1974 Norton 850 Commando Roadster

09-12-2011, 08:14 AM	#58
Sniper X De Oppresso Liber Joined: Jul 2006 Location: Central New Mexico, 7420ft above sea level Oddometer: 30,297	Very nice indeed. I loved the way Yamaha painte dthe bikes in the 70s. I worked for a local dealer when they were new, in the mid 1970s until about 1978. I loved the Yamaha XS650 and the TX series and until everyone at the shop ragged on the TX750, I thought I wanted one. But I had a Daytona RD400F and since it was faster, and so sexy looking, I never got a TX750.....Beautiful work and hope it lasts forever. I hear riden as they should be they can be quite reliable. __________________ "I claim to be frightened of horses but do so only to get out of attending parades. It's peculiar but ...it works. The Horses get it. RESISTANCE IS NOT FUTILE. IT'S VOLTAGE DIVIDED BY CURRENT

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01-20-2010, 06:51 AM	#46
Motoduc1 backtrackvideo.com Joined: Jun 2006 Oddometer: 829	This might be just folklore, but I once heard that Yamaha actually dispatched a squadron of technicians from Japan to the U.S. just to go around the country and repair TX 750 models. If that story isn't true...it oughtta be!

06-29-2010, 08:52 PM	#50
s10rat Beastly Adventurer Joined: Feb 2007 Location: around the world soon Oddometer: 2,017	looks nice beside the goofy looking handlebars....

06-30-2010, 02:33 PM	#51
ken_the_carp Adventurer Joined: Jan 2006 Location: Montreal Quebec Oddometer: 70	I also worked at a Yamaha dealer when the TX750 was introduced, it was Yamaha's flagship, glorious in it's original metallic gold. The one sitting in our showroom came with a large box of engine parts to be installed before being sold. The omi-phase harmonic balancer had no provision for balancer chain adjustment, a kit was provided with an eccentric shaft and locking system. After about 3000 miles the weights started wearing the sides of the cases and we tried to remedy this by added 4 small radial bearing. The main oil gallery was behind the points, oil constantly leaked into the points compartment, we changed the seals several times. Yamaha sent us a new style labyrinth seal, didn't stop the oil, eventually they suggested that we drill a small hole in the case to prevent accumulation fouling the points. The engine had double cases (cosmetic covers to hide the functional engine cases). An exhaust crossover was part of the cylinder head needlessly the engine ran very hot, the oil temp was at the upper limits of normal motor oil (not sure I think about 270 deg.F). Yamaha added a sump extension. Oil capacity was close to 5 quarts. There were some strange electrical issues, a contact was imbedded in the rear brake shoes to light a brake wear indicator on the dash. There was talk of this current "bleeding" back into the electrical system and engaging the starter, this could happen at any time/speed. I did see a TX750 with the crankshaft protruding out of the front of the engine. Sorry, I'm not trying to put the bike down, just an old fart who thought they were pretty cool just brought to market too soon. I remember holding one WOT going down a grade, the speedo was reading 128mph. Ken

07-01-2010, 04:27 AM	#53
Richy Studly Adventurer Joined: Sep 2005 Location: FL Oddometer: 507	I bought one new, Yamaha left me hanging. I've had a lot of new bikes since then, no Yamahas. I really like that bike too, it ran and rode well.

09-11-2011, 05:28 PM	#55
zoo mob Gnarly Adventurer Joined: Aug 2009 Oddometer: 315	Great work! Though I'm scared to get involved with one of those, I sure like the way they look and would love to take one for a ride.

09-11-2011, 06:32 PM	#56
NHNRS n00b Joined: Oct 2010 Oddometer: 5	I think I saw your bike today in North Brookfield. If that was it, very nice work!