74 shock mount photos needed

[tony27]

I need a couple of decent shots of the shock mounts on the 74 swingarm for GMC to make a repair/modification
I picked up what I think may be a 76 Falta arm that has had the original mounts & torque arm anchor point removed, a rather ugly set of mounts have been bronze welded on in about the same place as on a 75 arm

What I have as a starting point, don't feel guilty changing it because of what has already been done

[ozktm]

Best i can get in the position the bike is in...

[tony27]

Thanks to roughrider I now have what I hope is enough detail shots of his mounts which have been modified for a laid forward conversion but not by enough that the original shape & size isn't able to be worked out
I'll put a link up to my Photobucket folder with the info & lots of shots of 74 swingarms for future reference
Now I just need to confirm if there is enough info & if GMC feels like getting some beer & pie tokens off me to do the work 

http://s788.photobucket.com/user/tony27_photo/CZ%20981%20random%20stuff/Swingarms/story

[Mick D]

Hi Tony, I bought this 74 braced arm of an ex Brad Lackey Special
Click on pic for link, there is heaps of seller pics there that you download

[GMC]

Now I just need to confirm if there is enough info & if GMC feels like getting some beer & pie tokens off me to do the work 

Hmmmm pies, you got me interested

Can anyone confirm these dimensions and supply 'A' - 'B' - 'C' - 'D' & 'Z' ?

[Mick D]

I will do it right now mr Morris

[Mick D]

I am loading now on purpose, then I will continue editing to finish.
That way if this laptop just shuts off like sometimes it has   Progress will saved and it will save me from becoming really unhappy.

Ok, measured both sides of course, to be sure.

A = 19

B = Isn't that simple, it is 19.5 from center of hole to directly below it, but the plate needs to go down deeper at the front and rear so those points can be bent in to meet the arm tube


Alignment is the inside of outer plate with outer edge of axle slot.


20.5 is the inner gap between plates(Shocker eye bush width = 20, identical to the inside width of the top frame mount) Confirmed. So I imagine that they did it at 20.5 to provide for a paint allowance.

When I need to raise plans from pictures, I adjust screen size so to select the correct drafting scale rule by matching one to a known dimension. Check arm, pics and calculate. I am in no doubt you would have constructed many a good outcome from pics. Let me know if you want more.

C = 50.5 and the overall length of that inner LH plate is 86 on mine, not 83. That inner plate becomes a little shorter on the RH side after being intentionally deformed by a depth of 2.8 to move the shocker out to clear the chain and sprocket fastenning bolt heads.
Also Note; the thin HT nut brazed to the inside of the RH inner plate.

 

D = 9.5

Z = 10.5 (probably 11 without paint) and a bar for a press tool, with a radius of 20 (diameter 40), with the center of the depression being 74.5 from the very end of the arm.


So the bottom edge of the outside RH plate has to get bent in even more than the LH one, to be able to meet its weld. Indeed it is way more deformed than the one on the left side.



I can hardly believe how slow Picture Pale becomes when the Americans wake up and choke its portal to capacity.
That's your quota for the year too Geoffro 
Nah, just kidding,
Anyhow
Good night Irene
 

[Mick D]

PS; as I was saying in my first post, click on the pic. It will take you to my purchase. The listing is still active ATM and there is a lot of seller loaded pics there as well.

[tony27]

Are you sure that the right side inner mount should be kinked inwards, the Falta arm I'm using at the moment is straight on both sides & they sit further in due to the width of the air shocks. There isn't any clearance issues with the sprocket bolts etc but I do have the ohlins shock spaced to the outside to increase the clearance which is easy with how narrow the eyes are compared to the mounts, I do the same on the other side to get the shock away from the pipe
I wonder if the kink was something to do with lining things up in the Maico frame that the listing said it was used in, the photos in my folder look like it should be straight

[tony27]

Managed to luck onto a proper 74 arm last week, on it's way from the states via ebays global shipping program so I might see it before the season is over 
When it does arrive I may give both it & the damaged Falta arm to someone for copying & have a tab added for locating a chain slider, things have been seriously stalled for a while


To me it doesn't look as though the chain side inner mount has the bend that Mick's has

[Mick D]

Good pickup Tony They certainly don't come up very often.

Are you sure that the right side inner mount should be kinked inwards, the Falta arm I'm using at the moment is straight on both sides & they sit further in due to the width of the air shocks. There isn't any clearance issues with the sprocket bolts etc but I do have the ohlins shock spaced to the outside to increase the clearance which is easy with how narrow the eyes are compared to the mounts, I do the same on the other side to get the shock away from the pipe
I wonder if the kink was something to do with lining things up in the Maico frame that the listing said it was used in, the photos in my folder look like it should be straight

I am only sure about death and taxes.
The mount on mine is "Outwards", your on the right track though, here is a pic of how it was to accommodate the rear shock on the drive side


I guess I should change it back, what a pain

[tony27]

Nothing you couldn't handle. Interesting to see the bend in the brake stay to clear the added on bracing, Brad certainly must have been hard on bikes if they did that for him. I'm planning on getting a Wheelsmith replica stay/chain guide off AMS Racing when Dave emails me to say he has them back in stock, will use the spring loaded 1 that is included until then as my current Pro-tec is eating itself & no longer sits square
I got an email from eBay saying that it has cleared customs but when I check the tracking it says shipped to international destination 2d 20h ago. Hopefully that means it actually is in the country & I'll get the chance to quickly spray it black & get it fitted in time for next round of the eNZed series next Saturday
Have had a couple of very good wins in the last couple of weeks, won a 8 petal DH reed assembly earlier in the week for $50us which doesn't show as being sent yet but made turn up to my US address in the next few days. Will have to keep away from the site for a while as the swingarm was really the last part I was after

[tony27]

It arrived while I was asleep today  .
Both sets of mounts are straight & measure 20.75mm across, I need to make new bushings with 8mm holes instead of 10mm like the Falta arm took for my Ohlins sometime around 1am at work while it's quiet & I'll probably make them 20.5mm long with washers built in to help with chain & pipe clearance
Have given it a quick rattle can job which only has to last until early December when we get a mid-season break then I'll strip it back properly & have the chain grooves filled in at the pivot, a tab for screwing a chain slider block against to prevent it happening again welded on & then paint it properly

[Mick D]

Sounds like a good plan.
Are you using these 74 style arms on 73 frames?

[tony27]

Sure am, bolt up exactly like they are meant to be there.
When I first fitted the 76 Falta arm I had to shorten the bearing tube in the hub & sort a longer brake stay. Allowed me to fit the straight underslung brake rod connecting up to the longer curved brake arm
The bike seems to have grown a few Falta parts in the last couple of years, tank & cylinder as well now