FF: Forks Hyperpro damper assembly

macvette

Well Known and Active Forum User
Non-VOC Member
View attachment 17843 View attachment 17844
I got this damper from EBay. It has a 75 mm stroke. I have prototyped a bracket in 3mm aluminium as shown but because it was made with hand tools, I simplified it to the sketch shown. The real bracket will be made in 10mm billet alumium.
The difference in shape and dimensions between this and Vincent's is because it is to fit the modified steering stem and the body pivot puts the damper further towards the front of the bike. With this set up, there is about 20 mm of travel left lock to lock and this can be equalised by adjusting the damper body in its clamp. I prototyped this on the bike without the forks but with the lower link (With sealed bearings) but I'm pretty confident that it won't foul the spring boxes. The main bracket will be spaced down with a modified 6 mm thick version of timetravellers three hole bracket without the damper rod pivot hole. This is so that there is clearance for the near side eccentric from the 10mm bracket and to provide a flat bearing surface on the underside of the new steering stemThanks to Greg and Vincent for their help.
Latest version of " Chinese damper" install. My bike is a Series D with modified steering stem and bearing mod to the lower link.
When I made the damper bracket in the drawing and mounted the damper on the bike with the above mods, I mounted the damper ahead of the body pivot bracket as shown in the first picture (085400). I wasn't happy with the clearance of the damper rod and the right hand spring box so I mounted the damper behind the pivot point but wasn't happy with the clearance between the damper body and the front cylinder. As a result I sourced a damper body bracket whose pivot point was on the body centre line and fabricated the actuating bracket you see in the second picture (094801). The bracket is made from 10mm thick rolled aluminium and has a 6mm spacer between it and the flat underside face of the modified steering stem. The spacer is relieved to fit over the protruding stem. The mounting for the damper pivot was made from 17 mm Stainless hex bar turned down and threaded 3/8 Bsw to fit into the original damper stop hole which O tapped to match. The other end of the SS was drilled and tapped to match the damper pivot bolt supplied with the centre line body bracket. The third picture shows the final version.
20171216_085400.jpg
20180107_094801.jpg
20180104_194706.jpg

Regards Mac
 
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timetraveller

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VOC Member
Just to express public thanks to Mac here. I ordered a damper from China via EBay well before Xmas and after four weeks it had still not arrived and I got my money back. Then Mac PM'd me to show me what he had done and gave me the EBay numbers of the parts he had used as I was struggling to find the items although I used all the various forms of words I could think of. I bought the damper which was suggested by Mac and also a mounting kit which one has to buy in order to get the one component one needs to mount the damper body directly below the fixing point on the UFM. The kit costs £30 while the damper is only £25 so being a tight a**e and trying to save people £30 I have designed a system to go offset under the hole in the UFM. I made lots of plywood models before I got what I hope is right and I have just had a phone call to tell me that the laser cut parts will be ready this afternoon but the space still needs to have a hollow milled out. If I have it right then you have all saved £30. If I have it wrong then that is my problem. We will see.
 

timetraveller

Well Known and Active Forum User
VOC Member
P2110253.JPG
Here, hopefully, are some pics of the Chinese damper fitted to the front end, which is being held vertically in a 'workmate'. The picture show the system at two extreme positions which give about 6 mm (1/4") clearance at each end of the movement. The crash bar was fitted to ensure that there was clearance for that. The third picture show a view from the side to show the clearances.
P2110251.JPG

P2110252.JPG
 
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