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Rebuild a 250 Alpina 1974 type 115

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  • Author

Sunday job 😃...

I have a small issue with the kickstand bought on Ebay, I will have to cut the base and weld it properly... 

Next job: fork seals 😬...

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  • Author

last news:

The broken spokes in the rear wheel were replaced by my local mechanic ...

The fork is on way to be rebuilt, I am fighting with the old seals 😒.

Good news: I found oil in the tubes, without water. I succeed to remove the retaining screws from the

bottom of each tube. 🤪. The circlips to keep the seals in place are out of order 😌.

 

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58 minutes ago, Divouneh said:

Question: why 2 stops for the spring ?

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Those things are preload spacers. You can adjust the spring preload by fitting more or less of them

  • Author

Damned; Each fork leg has two seals; I need to order another set 😔.

The main job is to disassemble and clean, small delay...

You really don´t need two seals/leg. One quality seal (like skf or similar) is adequate, but you may have to manufacture a spacer for the missing seal. I have found "all balls 35mm fork seals" to be not good at all. Life is OK but the friction.........🙄

Benefit is lower friction (not all balls), which is needed on these old forks

As far as I can remember the seals are 35x47x10. They don´t need to be 10 but a spacer might be needed. A spacer can med machined from an oil resistant plastic.

Make sure you don´t damge the seal when assembling. That is very easy to do (yes I know😢).

The stanchions should be in good condition otherwise they may leak.

Leaking seals can be cleaned between the seal and stainchion by inserting a deburred feeler gauge. Some x-tra life can be gained, but only if the stainchion is in good condition

Edited by carl ekblom

  • Author

"Benefit is lower friction (not all balls), which is needed on these old forks" good remark. 

I bought double-lip seals, machining the spacers will cost me more than a new set of single-lip... 

Thanks again for the support 🙂

 

 

 

 

  • Author

Cleaning the fork cups: my springs (13) are dead, I have seen the same size in my ball pen 🤫.

It will work 😃...

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I have replaced the bloody "All Balls" seal today with "Ariete 012" which I hope will have lower friction. The All Balls dust scraper remains.

Original are 2 fork seals and one external dust cover but no locking ring.

For me, one fork seal,  spacer and one dust scraper and still no locking ring. It has worked for me before. Perhaps the locking ring isn´t needed but I would like to see one above the fork seal for safety´s sake.

I have several SKF scraper rings but they are 47.8mm and some turning is needed to make them fit properly. The fork seal from "SKF Kit 35M" would fit but they are expensive. Hoping the Ariete fork seal is a cheaper alternative. Unfortunalely I have no SKF fork seals lying around today but will be interesting to find out about the cheaper Ariete option.

Perhaps the original two fork seals are because of the not very effective external dust cover🤔 If I had the dust cover instead of a the more modern dust scraper ring i think it would be good practice to clean under the dust cover after a some hours of running.

The most recent fork work I did on a Bultaco included green SKF seals with spacer rings I made from PVC electrical conduit (in a model 49 Bultaco). I wouldn't normally bother with fork seal spacer rings but the seal seller told me that the SKF fork seals are more prone to moving within the slider than other brand seals.

I found the SKF seals do function exceptionally well.

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