1991 SE1000

petergt4

Well-Known Member
Hi !
I am also restoring a SE 1000, can you tell me the dimension of the allen key from the countersunk screws which are fixing
the swingarm. ( i think its not metric, i am from europe so it is a little bit diffcult for me )

Black Lightning is correct, you need a 7/32" Allen key. It is best to have the correct size key, as these bolts tend to be tightened with Loctite and can be difficult to loosen. A poorly fitting key may strip out the hex in the bolt.

The bolts are inch threads, which measure 3/8"-16 and they are each, approximately 1" long. If you need some, I have plenty of stainless ones.
 

kurbelwuerger

New Member
Hi!
Thanks a lot for your answer. Now i have another problem: I have loosened the right screw but I cannot the left screw because i can't fix the axle (it keeps turning). Is there any trick i to loose both screws?
 

petergt4

Well-Known Member
Hi!
Thanks a lot for your answer. Now i have another problem: I have loosened the right screw but I cannot the left screw because i can't fix the axle (it keeps turning). Is there any trick i to loose both screws?

Yes. You will find a small hole (that is covered by a small plastic cap) above this axle, which will allow you to insert a pin (of a suitable size, like another Allen key) into a corresponding hole in the axle. This will lock it in place and you will be able to remove the other screw. See my photos:

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petergt4

Well-Known Member
Okay, so the project continues.

I worked on cutting out the cracked chainstay bridge on the rear swing arm. It explained a lot once it was cut out. First off, the tubing is super thin - approximately 0.032" wall thickness! It also appears the fit up was quite sloppy! Instead of the tube being accurately mittered for a perfect fit, it appears there were huge gaps and weld was solely used to fill the gaps! It can be seen as my saw blade cut right through one of the lumpy welds. One of the cracks starts immediately from the edge of that lumpy weld.

The piece of tubing I'm using to replace it is nearly twice as thick (approx. 0.055") and I will accurately fit it to the swing arm frame, so that should prevent it from cracking again. Considering this is very close to the swing arm pivot and no other material in the area to distribute stress, this is a critical piece.

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petergt4

Well-Known Member
I also worked on the head tube crack reinforcement gusset by creating a paper template. It's somewhat heart-shaped except with no sharp points or edges. I'll trace it out on the piece of tubing which will hold that curved shape to the frame tube. It's wall thickness is 0.060" and it, along with the chainstay bridge tube are both 6061-T6 aluminum.

I bought enough tubing to use as practice pieces so I can set my welding machine to the right amount (amperage, AC frequency and wave balance, etc.) before laying down any permanent weld on the frame.

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petergt4

Well-Known Member
I welded up the head tube crack and installed the reinforcement patch. The crack welded up nicely, without any debris or contamination bubbling out (a good sign it was thoroughly cleaned out). After welding the crack, I ground it down so the reinforcement patch would fit tightly to the frame over top of it.

Overall, the amount of heat I put into this area isn't as much as I thought it would be, considering how aluminum sucks up and dissipates welding heat so readily. I was running about 60 amps for the crack and the lower portion of the patch and about 80+ amps for that patch beside the head tube weld. I have a lot of confidence that the heat treating has not been adversely affected.

The next repair will be the rear swingarm, so hopefully I'll have some time during the holidays to at least prep those pieces.

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petergt4

Well-Known Member
Well, the holidays were too busy and I didn't touch the swingarm until now. I ground down and sanded smooth the welds from the removed, cracked chainstay bridge and prepared the new bridge for welding. Both the pivot and dropouts are held in place to keep their dimensions in check, to prevent shrinkage from welding distortion.

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black lightning 1987

Moderator
Staff member
Looking great. It's nice to see you putting so much work into the frame. I don't think I've ever seen one in the wild, only in the shops when they were current.
 

petergt4

Well-Known Member
Looking great. It's nice to see you putting so much work into the frame. I don't think I've ever seen one in the wild, only in the shops when they were current.

This is the bike that got me hooked on Mountain biking and Cannondale and so it means a lot to me. They're a significant part of mountain bike history too. They're worth saving.

And boy, when it's done, I'm going to ride the wheels off of it! :)
 

black lightning 1987

Moderator
Staff member
I wish I was as motivated as you. I have most of the parts to reproduce my first Cannondale but keep doing other projects instead of getting the paint work done.
 

petergt4

Well-Known Member
I wish I was as motivated as you. I have most of the parts to reproduce my first Cannondale but keep doing other projects instead of getting the paint work done.

Motivated? More like determined! Much like you, I would’ve liked to have finished this a while ago, but I have too many other projects on the go and get easily distracted. Staying as focused as I can...
 

Guy Redshaw

Active Member
Well, this has been in the making for 27 years... Finally got my hands on an original EST suspension bike, a SE1000, as a frame only.

This project will be over a long period of time, so I don't know when it will be completed, but I already have the majority of components, so it's just a matter of cleaning everything up.

I will make use of my long out-of-service first gen. Girvin Vector fork, which I had originally run on my Killer V 900 (which I now have returned to fully rigid as I kept the Pepperoni fork that came with the bike). This will require most of the project time as I have to adapt a Fox coil-over shock to replace the garbage elastomer shock that was originally installed.

I haven't decided to keep it the original silver color, or go with a custom scheme. I have some ideas, that would be in keeping with the era (although nothing as vivid as the SE2000 neon pink/green/black combo ;) ).

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Very Kool! Spynergy wheels as well...?
 

Guy Redshaw

Active Member
So, when I bought this frame, it was disclosed that the rear swingarm had a cracked chainstay bridge. Considering that, I decided to check out the front triangle for any other possible cracks and I found one... Just under the downtube at the headtube junction. From what I can tell, it looks like there was a sharp transition of the weld, which caused a stress-riser and then pop, a crack. No help from Cannondale's trademark sanded-down welds, which may have been a thinning of the tube at that area.

I'll fix both. There's debate online of whether an aluminum frame needs to be heat treated or not with a welded repair, so I'm going to have to investigate this further, in person with nerdy, industry types to confirm heat treatment or not. The welding is a non-issue for me. I'll replace the chainstay bridge with a new piece of tube and the downtube crack will be welded, with an overlay patch for reinforcement. No prob...

How I found the crack was using a two-stage penetrating dye that is used for non-destructive crack and leak checking (which I do often in my line of work in the petroleum industry).

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Very interesting way ofcrack testing. Thanxfor sharing.
 

Brian

Administrator
Staff member
It looks like you are making progress! I still can not believe it had that crack. I guess we all get old age. Is the frame almost done?
 

petergt4

Well-Known Member
I had a chance earlier this week to weld up the chainstay bridge for the swing arm. A bit tricky welding the tube on the side where the suspension pivot ears are, despite it looking like there was a lot of room, as there wasn't (even with using a short cap on the TIG torch).

That takes care of the major welding repairs for this frame. Although, there are some cable stops that have been chewed up a bit (probably from hitting a rock, or something else hard). I'll see whether I'll just file off the messy bits, or maybe those need to be repaired with weld as well.

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