750/850 front fork head stop

nortonisthebest

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Aug 1, 2014

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122

• Jun 19, 2016

• #1

Can anyone post a picture of a 750/850 front fork stop that is welded on the yoke head. Also would appreciate approximant measurements. Some one cut the one I have off. Also is a 850 frame # F103849 the same as a 1971-73 750 frame? I compared the to frames and they look identical to me. Thanks.

 

L.A.B.

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• Jun 19, 2016

• #2

nortonisthebest said:

Also is a 850 frame # F103849 the same as a 1971-73 750 frame? I compared the to frames and they look identical to me.

Click to expand...

There is a one degree difference in headstock angle between '750' and '850' frames (see manual, section F, Fig.4, pdf p.90).

Also, read section G3, note Re: 850 "ANG" yokes:

http://britmoto.com/manuals/Manuals/750_man.pdf

 

Danno

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Feb 7, 2010

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4,195

• Jun 20, 2016

• #3

The fork stops are set to keep the tubes from banging into the front sides of an Interstate tank. If you have a Roadster tank, the stops on the bottom yoke can be set a few degrees further out on each side. With a Hi-Rider tank, even wider. The stop lug on the steering neck is welded on right in the center of the lower front side of the tube.

 

nortonisthebest

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• Jun 20, 2016

• #4

It appears the 850 frame can be used on a 750 commando. The only major difference is the 1 degree head angle. I'll let you know how everything go's after I put it all together. I've also been told that the 850 yoke has a different angle then the 750 yokes. I plan on using the 750 yoke on the 850 frame. There is a slight difference but it should work ok. No one knows why Norton changed the head angle and yoke on the 850's. Thanks for your input.

 

Danno

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• Jun 20, 2016

• #5

I always thought the yokes were parallel to the neck and that the 1 degree extra was added for slightly more straight-line stability since the 850s (especially the e-starts) are a few lbs heavier than the 750s. Not sure if the offset differs between 850 and 750 yokes.

 

L.A.B.

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• Jun 20, 2016

• #6

Danno said:

I always thought the yokes were parallel to the neck

Click to expand...

850 yokes aren't, and why they are marked "ANG".


split-topic-triple-trees-t5729-45.html#p55362

split-topic-triple-trees-t5729-60.html#p55429

 

R

Rohan

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Aug 26, 2010

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8,215

• Jun 20, 2016

• #7

Has anyone confirmed DynoDaves measurement ?

When you eyeball the forks, the tubes are kicked backwards quite noticeably compared to the steering head.
The top yoke is extended out quite a bit compared to the bottom yoke.

 

nortonisthebest

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Aug 1, 2014

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122

• Jun 20, 2016

• #8

According to a well known Norton source, the 850 Yolk's are not inline with the steering head. The 750's are straight with the steering head. This is what I understood from the Norton source. By using the 750 Yolk it should not make much difference in handling and should be safe.
There are some improvements to the 850 frame vs the 750 frame, such as the rear shock mount inside reinforcement gusset. Everything should fit the same for both 750 and 850 bikes.

 

Danno

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• Jun 20, 2016

• #9

So, 3mm offset diferential (72mm top, 69mm bottom) with 850 yokes and 65-65 with 750 items. I have an entire 850 MkIII front end on my 750 frame. Would be interesting to know what they were thinking when they added a degree of rake (28 as opposed to 27) and then took back the extra trail with non-parallel yokes. Due to the fact that BOTH 850 items had more offset than the 750 parts, maybe the contact patch ended up in the same place??????