Author Topic: Yamaha History Buffs - Help Needed XS750 - 1972 200 Made? (Read 13129 times)

RRRToolSolutions · « **on:** January 30, 2009, 08:27:25 AM »

Fellas, I have a very good friend who has just purchased an awesome 1972 Red/White XS650 with 1,100 original miles. The bike is just fantastic. Paint, seat, rims/spokes - untouched, unmolested. He called me last night and asked me to help him trace down one little issue.

The owner says this bike is one of 200 1972 XS650s to have a factory installed "750 kit". The story goes that Yamaha gave full factory warranty and put these out there to test the durability and acceptance. The cylinder is even stamped "750cc".

What gives? Anyone ever heard of this?

Thanks,
Gordon

hoodellyhoo · « **Reply #1 on:** January 30, 2009, 08:37:27 AM »

never heard of it but I wouldn't mind seeing pictures of the rest of the bike

SteveD CB500F · « **Reply #2 on:** January 30, 2009, 09:07:17 AM »

So it's an XS650 twin with a factory 750 kit? I thought all the XS750s were triples?

fishhead · « **Reply #3 on:** January 30, 2009, 10:40:17 AM »

Is the front left side valve adjuster cap a 3 bolt cap? Are all the valve adjuster caps the same?
The front left side valve caps were usually 4 bolt and different from the rest of the valve caps.
Does the exhaust pipe exit the head straight foward- I mean straight towards the front wheel? Stock usualy has it coming out going to the front and off to the side.

RRRToolSolutions · « **Reply #4 on:** January 30, 2009, 11:16:56 AM »

Guys, this fellow knows Yamahas - his 1971 Gold/White XS650 has won 1st place at the Barbers VJMC show every year. He has 2 1971's, a 1973 TX650, a 1978 triple 750, an several other models including old two strokes and a brand new FJR.

Here is the all-original XS650 - that is original paint, the fender doesn't even have rust underneath. The engine cases are 1972 cases - not an engine swap. If Yamaha didn't do it, then we're thinking maybe a dealer with access to Shell dirt track parts back then. This bike has not been touched or ridden in 30 years. Look at the inside of the chaingaurd on this red 1972 1,100 mile bike! The only thing we can find on his not stock is the mirror, rack, and crashbar. The handlebar, switches, seat - everything else looks stock. Anyone putting a 750 kit in for performance would have changed the carbs, pipes, and air filters - these are 100% stock.

The last 2 show both and my 1973 TX650's.

Gordon

HavocTurbo · « **Reply #5 on:** January 30, 2009, 11:27:04 AM »

There's no reason to say that someone didn't put in a 750 kit without changing any of the required parts for performance.

It's my understanding that there were several "teams" out there that sold "performance" kits to dealers in hopes of larger markets later.

Russ Collins did it with the CB750 so why not someone with the XS650.

My local Honda dealer had several RC "kits" for factory install. All of which used the stock airbox and exhaust. Only way totell them apart was the giant RC machined (or cast) into the side of the cylinders. (later confirmed by a former employee for Russ)

Not saying that that is what this is..... but throwing another idea out there.

fishhead · « **Reply #6 on:** January 31, 2009, 07:46:46 AM »

Quote from: Ilbikes on January 30, 2009, 11:16:56 AM

Anyone putting a 750 kit in for performance would have changed the carbs, pipes, and air filters - these are 100% stock.

Usually, but if the stock 650cc cylinders were bored out, they would still have "650cc" cast in them instead of the "750cc" that yours have.
I've been told that Yamaha made a 750 kit for their factory racers (to compete in the 45CU/750CC classes) and that would account for the "750cc" cast in yours. I know the racers had different head as I have had 1 of the race heads (all 3 bolt valve covers, different exhaust angles). Yours looks to have the stock head with the compression release.

754 · « **Reply #7 on:** January 31, 2009, 08:41:35 AM »

Are the numbers, innies or outies?

on some big bore, folks filed off the number, and restamped.

crazypj · « **Reply #8 on:** January 31, 2009, 09:15:47 AM »

If our not already a member, join here and post question.
Someone will probably know full history
http://xs650temp.proboards29.com/index.cgi?

PJ

fuzzybutt · « **Reply #9 on:** February 01, 2009, 03:03:36 AM »

those sure look like "outies" to me.

crazypj · « **Reply #10 on:** February 01, 2009, 02:19:15 PM »

I just had a better look at it and it looks like its stamped 707cc which is a 78mm overbore on stock block
PJ

TZ750 · « **Reply #11 on:** May 08, 2009, 08:15:56 PM »

Gordon,

Yamaha did make 200 1972 650s with 750 cylinders to satisfy the AMA homologation rules for racing. I also have one of these bikes. Although a lot of people have added big bore kits to their 650 these 200 came with 750 sleeves already installed. They are not aftermarket kits and as you know from your friends bike, they came with stock carbs, pipes and air filters. I was at the yamaha shop when my bike was unloaded NEW from the truck. the yamaha dealer kept it as his personal bike for a couple years then bought it. Does the serial number on your friends bike start with S650 0r GS650?

Bob

cb650 · « **Reply #12 on:** May 09, 2009, 04:59:54 AM »

Quote from: SteveD CB500F on January 30, 2009, 09:07:17 AM

So it's an XS650 twin with a factory 750 kit? I thought all the XS750s were triples?

They did make a 750 twin but dont know if it was a XS. Didnt look like the 650. Only ever seen a few. Did see a nice 80 or so XS650 special in trafic yesterday. Used to have a 77.

Bob Wessner · « **Reply #13 on:** May 09, 2009, 05:02:12 AM »

Quote from: Ilbikes on January 30, 2009, 11:16:56 AM

Guys, this fellow knows Yamahas - his 1971 Gold/White XS650 has won 1st place at the Barbers VJMC show every year. He has 2 1971's, a 1973 TX650, a 1978 triple 750, an several other models including old two strokes and a brand new FJR.

Here is the all-original XS650 - that is original paint, the fender doesn't even have rust underneath. The engine cases are 1972 cases - not an engine swap. If Yamaha didn't do it, then we're thinking maybe a dealer with access to Shell dirt track parts back then. This bike has not been touched or ridden in 30 years. Look at the inside of the chaingaurd on this red 1972 1,100 mile bike! The only thing we can find on his not stock is the mirror, rack, and crashbar. The handlebar, switches, seat - everything else looks stock. Anyone putting a 750 kit in for performance would have changed the carbs, pipes, and air filters - these are 100% stock.

The last 2 show both and my 1973 TX650's.

Gordon

Gorgeous Yamahas! Personally, I think they are the best looking twins ever made.

fishhead · « **Reply #14 on:** May 09, 2009, 05:13:57 AM »

Quote from: cb650 on May 09, 2009, 04:59:54 AM

They did make a 750 twin but dont know if it was a XS. Didnt look like the 650. Only ever seen a few. Did see a nice 80 or so XS650 special in trafic yesterday. Used to have a 77.

They made the TX 750 (twin)

http://www.tobyfolwick.com/tx750/

BeSeeingYou · « **Reply #15 on:** May 09, 2009, 12:24:46 PM »

The notorious 73 TX750. Engines tended to blow because of an oil circulation problem at high revs. Had a few other issues but most of them were fixed in the 74 model but it was too late as the reputation was shattered. The 73's will survive if not run hard and some are still around. Very smooth bike due to the counterbalanced crankshaft. Suprisingly there are three 73's for sale locally, two in running condition with 10K and 14K miles. The 74's seem harder to come by but would be the better choice. They have little to no collector value and can be had cheap so if you like a challenge and want something unique in your stable.... I have been tempted but I am holding out for a 75 XS650, the best looking of the XS's IMO. I would also agree that the XS650's are the best looking twins even better than their direct influence, the Bonneville.

Retro Rocket · « **Reply #16 on:** May 10, 2009, 04:28:40 PM »

+1 Bob, definitely the best balanced looking twin ever made. I did a lot of research on these a couple of years ago and i'm not to sure where i read it but i did read that Yamaha released a limited amount of these bikes with a factory 750 kit, i have a pile of bookmarks for 650's so when i have the time i will go back and see if i can find the article i read about this.

Mick

rodeoman · « **Reply #17 on:** October 20, 2009, 07:15:00 PM »

I have one and I want mor info, mine has a slightly difrent frame, is that what everyone else has found??

BeSeeingYou · « **Reply #18 on:** October 20, 2009, 10:16:41 PM »

The XS650 frame was changed and improved in 1974. The most obvious visual clue is the passenger foot peg mount. The early years this was a pressed steel arm and the later it was a tubular loop. Engines and frames swap though the years so it is not unusual to have mismatched engine and frame years.

RRRToolSolutions · « **Reply #19 on:** October 21, 2009, 04:29:06 AM »

Guys, Barry brought this bike to Barbers 2 weeks ago. The bike is confirmed and documented by the Yamaha corporation to be #21 of 200 1972 Yamaha 650's specially built to 750cc by the factory to meet the production rules so Kenny Roberts could go racing with the 750. This bike's frame and engine number match to the digit and with only 1,100 miles is likely to be one of the finest examples of these left in the world. Most were used by racers to tear-up the tracks, used, abused, and replaced without thought. The frame has a unique prefix and serial number that identifies it as one of the factory 750's.

Regards,
Gordon

rodeoman · « **Reply #20 on:** October 21, 2009, 06:27:59 AM »

mine dose not have the "boss" or "bracked" for rear pegs, it is a #'s matching motor and frame, any more info out there to help me out

rodeoman · « **Reply #21 on:** October 21, 2009, 08:57:51 AM »

dose anyone know what the SN#'s are for these bikes???

RRRToolSolutions · « **Reply #22 on:** October 21, 2009, 09:38:58 AM »

Email me at eastg@bellsouth.net and I'll put you in touch with the man that knows just about everything Yamaha and is the owner of the bike shown.

Regards,
Gordon

TZ750 · « **Reply #23 on:** July 06, 2010, 10:41:39 AM »

The 200 bikes with a 750 motor were 1972 models made in July 1971 and the serial numbers were from GS650-102651 thru GS650-102850 Mine is GS650-102818 as you probably know a standard production 1972 XS2-650 has a serial that starts with S650-xxxxxxx these 200 bikes have GS650-xxxxxx serial numbers. I would like to see have many of these 200 are left. Check your serial numbers if it starts with GS650 instead of S650......... you might have one!

crazypj · « **Reply #24 on:** July 06, 2010, 09:53:38 PM »

Didn't they also have different cylinder head with repositioned exhaust ports?
(or is the OW31 a later motor?)

PJ

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Author Topic: Yamaha History Buffs - Help Needed XS750 - 1972 200 Made? (Read 13129 times)

fuzzybutt

rodeoman

rodeoman

rodeoman