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jchen
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Question: are the brakes on the 75/6 so much superior/safer that I would notice riding? Any other big differences between the two? Thanks!

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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Properly set up, drum brakes

Properly set up, drum brakes can be effective. But they can fade under constant use. The disk brakes, especially the drilled rotors, can be better in the rain.

The 5-speed in the /6 (with the exception of possibly the 1974 models) should be a better transmission. If it interests anyone, the last year of the /6 had the engine case opening increased to 99mm, up from 97mm. This was done as a transition to the /7 models and the 1000cc engine. Have the larger opening in a /6 engine would allow the direct bolt up of cylinders from later models. With the smaller opening, some machining, either the engine or the cylinder, has to be done.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

khittner
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Joined: 02/15/2012
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/6s Differ From /5s

jchen wrote:

Question: Any other big differences between the two? Thanks!

The whole thing is different, particularly by the time you get to the 1975 models.

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Konrad

Matteo
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Joined: 04/12/2010
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The thing to know about the

The thing to know about the /6 brakes is that the master cylinder is under the tank. There is a cable from the handlebar to the master cylinder and then a hydraulic line to the brake. I don't think I've seen a 40 year old master cylinder that wasn't leaking. If you are going to buy a /6, I would recommend removing the tank (pretty easy) and checking the master cylinder. When they leak they ruin the paint on the frame and can cause corrosion. Also, last time I had a /6 (about 10 years ago), I couldn't get the master cylinder rebuilt.

Many people replace the brakes with the later handlebar mounted master cylinder. Not sure if the /7 had the same system as the /6 or if they made the switch.

schrader7032
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San Antonio, TX
Joined: 10/27/2006
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The /7 still has the under

The /7 still has the under tank master cylinder...mine does. They can be rebuilt...the issue is replacing the internal o-ring which can be a byotch to get on but there are tricks to that. Also, there's is the matter of corrosion on the internal bore if the system is left too long. Usually a light honing with some sandpaper on a wooden dowel is all that is needed. There are brake repair places that can overhaul them and/or sleeve them with new material.

Personally, I don't see the big issue with the under tank master cylinder. With reasonable care, just about anything will work just fine.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

The Zieg
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Elizabeth Colorado
Joined: 05/27/2015
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If it's more than brakes

If it's more than brakes you're wondering about, the instruments are different. Inside the headlight casing and a bit on the horizontal in the case of the /5. Self-contained and on a more upright angle in the case of the /6. I prefer the /5, myself.

Zieg

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Zieg

pockomoth
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2 cents

At the time, the /6s were considered superior in just about every way, brakes, suspension with the longer wheelbase, etc. But the /5s were a little more fun to ride, turned in quicker definitely, but the brakes were scary. The bike weighed nothing and you could get going pretty well on that thing. So why am I not surprised that a bike that was considered superior in my day now is worth half of the first edition /5s? Go figure.

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pockomoth

slothy
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VBMWMO #9037
St. Clair Shores, Mi.
Joined: 09/29/2015
Posts: 53
i have a 73 75/5 toaster and

i have a 73 75/5 toaster and a r100/7 - the front (disc) are better brakes imo, 4 to 5 speed trans really makes no diff to me - seem to shift about the same.

i enjoy the 75/5 riding around then the r100, though the r100 feels like a rocket compared it that and my r50/2

A. S. Pels
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Joined: 09/05/2009
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A low-miles '73 R75 is a nice little bike

A low-miles '73 R75 is a nice little bike, but they don't tolerate crashes very well. The frames bend easily, and the forks must be aligned with extreme precision or they have "sticky" action. 1974 R75/6s still had the bushing rockers, and '74 5-speeds had multiple problems. Also, the only '74 with the double-tube frame backbone was the R90S, but the '74 /6 frame was stronger than the /5 frame even without that feature. The best 750 was the '77, but it had the cursed transmission intermediate shaft. Fix that and the '77 R75/7 is a pretty great bike.

pokie
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Joined: 02/08/2015
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Years of R75

All the R75s, like the other bikes had their idiot-synchrocies. In 1970, the advance mechanisms and carbs were the two big problems. 1971 was a pretty good year but still had leaky carb tops. 1972 could have been a good year if it wasn't for the transmission over shim problem, once the transmissions were properly shimmed, it was rare to have any other problems. 1973 was a very good year, in Canada, all we got were long wheel base machines. 1974 wasn't one of my favorite years, the new discs didn't work very well, especially in the rain. We weren't allowed to sell any of the bikes until the updated transmissions were replaced (seems a oil way was left out), the kick starts were marginal and in time, the transmissions proved to be inadequately designed and a rather large number of them failed. In 1974, the handlebar switches were the same as the /5 with the exception that the harness was longer and had spade terminals, different enough to make them harder to get. 1974 was also the year of the five position ignition switch, they worked ok but again, a little more difficult to find. 1975 was a much better year, drilled disc, 3 position ignition switch, different (and in my opinion better) handlebar switches. The flywheel bolts were larger to accommodate the power of the R90 (I never saw an R75 knock it's flywheel loose but did see several R90s do it with the smaller flywheel bolts). The transmission was a bit better but not much as now there was no kick start and shift springs were breaking and yes, the counter shaft was still too lightly built and the shift dogs were still breaking. 1976 was a pretty good year as well, still some transmission troubles but not bad.

In my opinion, if you want an R75 (my personal favorite), I would choose a 1971, 72, 73 or a 1975 or 1976. A 1977 was a pretty good one but I didn't much like the style ( again, just a personal opinion). My own personal favorite is a 1973 long wheelbase.

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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The '76 models had the 99mm

The '76 models had the 99mm case opening to accept the larger cylinder bases. This makes it easier to drop in cylinders from 1000cc bikes if one were inclined to that. Otherwise, some machining is needed to make that happen.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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