1989 ATK 406 Restoration

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11/6/2019 3:07 PM

I wanted to play with something a little more obscure and figured an ATK would do the trick. As a 10 year old kid I remember thinking these bikes were the answer to a question nobody was asking. They looked weird...and not in a good way. As time has gone by, I've gotten curious enough to seek one out and ended up finding this beauty a couple months ago.

The good, it was located a couple hours away (alot of others were West Coast or Canada), it runs, it is fairly complete and unmolested, has a cool Dyno Port pipe and was fairly cheap at $1100.

The bad, the body is scabby, the tires are shot, suspension is shot, and it appears to have been slapped back together hastily as if someone tossed some gas in it to see if it would run. Needless to say, it will need gone through before I can enjoy it.




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11/6/2019 3:19 PM

The silencer was bugging me. In the first video you can see the can was pointing up at the fender (actually into the fender). Once I got the side plate removed you could see it was bent badly at the inlet. All it took was unbolting the silencer mount, torching the bent section of steel tubing and giving it a proper heave downward. Presto, now its pointing straight.
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The other bad part is that the tire was getting into the side and chewed a hole through it. I decided to use some alumiweld rods with a propane torch to see if I could repair it. Those rods did the trick!
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After cleaning and sanding 75% of the rubbish out of the can
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Hole is filled and smoothed out
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I'm glad I pulled the core out, When the pipe bent, it nearly crimped the inlet of the core shut. That's all fixed up now
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Next up....the pipe was dented pretty badly and cracked in 4 places. I RTV'd the cracks shut and filled it with water to freeze. I've already got to weld all over it, so I'm not worried about more cracks. My wife was pretty understanding. I'm on the second trip to the freezer...will report in later.
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11/7/2019 10:17 PM

Cool to see a rebuild on such a unique bike! I'll be following along for sure!

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11/8/2019 12:18 PM
Edited Date/Time: 11/8/2019 12:20 PM

Thanks!

I'm posting up some of the pipe damage

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11/11/2019 8:58 AM

The freezer pushed this dent out almost all the way. But I'm going to have to weld it up a bit after the pipe split. At least the split gave me an access point to push the dent out further.
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I got to this point after several hours with a body hammer. For some of the sharp pits that I can't massage out, I will try filling with weld and sanding out. At least this is a natural finish pipe. I can't imagine what I would do with a plated pipe.
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11/11/2019 11:55 AM

Cool! I have wanted a 406 for a while, and I’m really not even sure why? Keep the updates coming!

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11/11/2019 7:18 PM
Edited Date/Time: 11/12/2019 7:25 AM

I spent a few hours welding and grinding. I underestimated the amount of work this thing would take. At this point all the cracks are sealed and the dents are basically all removed. I filled the dents that I couldn't remove with weld and ground it out to see what I had. I will have to go back over it with more weld in numerous areas.
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11/11/2019 9:27 PM
Edited Date/Time: 11/11/2019 9:32 PM

If you are really intent on making the pipe blemish free, you should probably look at getting bronze brazed on at sections. Easily filed / linished back, without the near inevitable 'pucking' at full, fusion welds. It can also be used to cover up rather ugly weld repair areas ( welding rusted steel, with shed loads of carbon, no matter how much you may have cleaned it out, makes for ugly, and weak, repairs - brazing over them, gives a spread out area of a repair) , and, as reinforcement that can be blended in at say, your split seam repair.

I'd love to get a 406 - the utter simplicity of them just gels with me. And, as I used an AMP Torque Limiter for many years on my CR/XR hybrids, and my 500s, I am used to the traits of them / the ATK (fuller) system. But, 406s are few and far between here in OZ, and, pricey if you do find one.

Are ADB still around / selling bits?

You're just a little fella, aren't you.......... w00t

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11/12/2019 10:26 AM

I don't have anything to braze with, so I'll just keep shooting weld at it and grinding. For full disclosure, I'm not sure that I can make this pipe look how I want, but I'll know afterward smile

ADB is still around. They offer some nice bits, I'll be sourcing most of the suspension components from them when I get around to rebuilding both ends of the bike.

And yeah, you remember my handlebar set-up on the CR500. I'll be doing something similar on the ATK to accommodate my tall frame!

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11/13/2019 6:32 AM

Nice build.theres currently an atk 560 for sale on eBay in pretty nice condition..good luck with your build..

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11/13/2019 3:24 PM

If you get the steel really hot with a torch and let it cool down before you weld it it will burn off most of the impurities caused by the carbon buildup making your welds significantly easier cleaner and stronger the ones are grinding down I guess it really doesn't matter however it'll be a lot less grinding Andre welding if it's a clean surface top and bottom youre welding on

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11/13/2019 8:15 PM
Edited Date/Time: 11/13/2019 8:25 PM

Thanks for the tips! I can use all the help I can get. smile
Tonight I went back over my welds. In my defense I really had no idea how much weld to build up in each dent. This time around I had an idea...and I went a little more generous in each spot. Here is a video of after the welding.



I was going to resist grinding tonight, but I couldn't. I hit a few spots to see how they looked and I am much happier with round 2.

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11/13/2019 11:22 PM

You're getting there, Shorty........

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11/19/2019 5:23 AM
Edited Date/Time: 11/19/2019 5:26 AM

MIcah, if that exhaust gets to be too much, well....I'll just leave this here...devil

https://www.ebay.com/itm/1995-ATK-406-EXPANSION-CHAMBER/323649448275?hash=item4b5b02a953:g:R~QAAOSwR0dcPO4L

No idea on the parts crossover between years...

Cool bike, brother!

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11/23/2019 7:37 AM

Micahdogg wrote:

Thanks!

I'm posting up some of the pipe damage

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I think I'm pretty much done. It didnt turn out as I hoped but it does look better.
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11/23/2019 8:40 AM

Natester551v wrote:

MIcah, if that exhaust gets to be too much, well....I'll just leave this here...devil

https://www.ebay.com/itm/1995-ATK-406-EXPANSION-CHAMBER/323649448275?hash=item4b5b02a953:g:R~QAAOSwR0dcPO4L

No idea on the parts crossover between years...

Cool bike, brother!

Thanks! That pipe you posted is for the newer 406. I can still get pipes for the older ones but I'm just trying to reuse what I can

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11/23/2019 9:34 AM

nice job on the pipe and nice job to your daughter on her fairy garden smile

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12/27/2019 7:40 AM

I started tearing the bike down to the frame for powdercoat. I was able to salvage the foil VIN tag with some dental floss. I believe that I've settled on white for the swingarm and frame.

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Before dropping it with the powdercoat guy, I need to come up with a footpeg solution though, since I want the brackets to be powdercoated white as well. American Dirtbike sells these IMS bolt-on beauties for $200. They are nice, but a little out of the budget so I picked up a set of KTM 450SX pegs for $25 complete with pins and springs along with some weld-on mounts for $18. I just need to sit down with the welder and drill press and I should be able to whip some up for about $50. Best part is I can weld them a bit lower for more comfort (probably 1/2 inch)

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Otherwise, I picked up a set of new Kenda tires, air filter, some plastic and I'm currently trying to source the inner/outer fork bushings for these WP 4054 Inverted 43mm forks. These are the first generation I believe since there are no adjusters. Here is a vid with some other details:

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12/28/2019 3:17 PM

Cleaned up the wheel, got the new tire and tube mounted, cleaned out the wheel bearings and tried to breath new life into them. They will work for a little bit but eventually they will need replaced.

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1/3/2020 7:44 AM

My awesome $17 foot peg brackets wouldn't work with the KTM pegs. Rather than try and work with them, I ended up bending some metal and making my own. They aren't the prettiest but thankfully powdercoat will cover a multitude of sins.

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Picked up some new plastic. This is Acerbis Nost front/rear fenders, which is what the bike should have had. Front fender has been revised through the years, most notably it no longer has the rear vents, but otherwise is the correct part and true to form. I went with a KTM front number plate though, which covers the lower clamp a bit more. I thought it looked a little nicer.

I'll refurbish the stock red side plates, which will take care of all of the plastic.

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Also got the rear wheel cleaned up and new Kenda mounted along with a fresh tube

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1/4/2020 12:18 AM
Edited Date/Time: 1/4/2020 12:20 AM

Good choice on the Pegs - as you've found, you can get KTM 'take offs', everywhere, and they are pretty good pegs in and of themselves. But, anything would be an improvement over the std ATK ones........

Making the mounts wider than the 22mm(?) of the KTM Peg width - I assume you are doing that for a bit of adjust-ability, like how some other aftermarket pegs have the reversible inserts? A Great idea! A bit of forward and back, and up and down to be had that way, with suitable spacers either side of the peg mount.

Another thing, as you are such a Shortarse........ KTM 450RR / Adventure Pegs are not only longer, and, a tad wider, fore and aft, but Lower than the std (up to 16 on EXCs?) pegs you are fitting. Something to keep in mind if you are going to be riding the 406 and still find you are 'folded up', too much.

You probably don't need this advice - putting a brace on the forward face of the mount you've done, to the mount plate, will make things very, very much stronger. A simple wedge from a bit of, probably, 1 inch square, is an easy to do reinforcement, and will present a 'ramp' for crud and impacts. I also use 10mm Stainless bolts with No threads bearing on the peg pivoting area, or the mount plates. I never have any Peg Pivot, or Mount wear sag, that way

Nost Fenders - I unpacked and packed hundreds of the bloody things when I worked at the OZ distributors, nearly 2 decades ago.

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1/4/2020 7:36 AM
Edited Date/Time: 1/4/2020 9:19 AM

The pegs actually fit flush in those mounts. There is a sizable boss on each side of the peg which you can't see in the pic. However, if I shaved them off that would give me probably 1/4 inch adjustability front/rear. What I also like about these pegs is they can easily be bandsawwed and rewelded 1/2 inch lower.

Did you work for ATK or Acerbis?

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1/5/2020 7:15 AM

No, the Australian distributor for Acerbis, UFO, MSR, PROX, Maico, Camelback - all at that time(s) - twice I was there for a few years, each time - and a few other products. Plus, a fair few other OZ Importers, Manufacturers, and Shops. And, with a couple of US and European Manufacturers, that enables me a lot of travel opportunities, still. All told, more than Four and a 1/2 decades in the Industry, and, I'm so very glad to be (semi), out of it.

Never ATK - but as I've said before, I would very much like a 406. I might have to be happy with my PDS'd Steelie, that I'll convert to a 'Finner', when I gather together enough parts to make a whole new 500 Watercooler, with, my own frame that I'll make. But, I've a few Ducati, Bicycle (well, quite a few of these, now I've the Pinion Gearboxes to hand) and Sport Sedan Chassis to make before then. Retirement, is a bloody busy time, I'm learning. dizzy

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1/5/2020 7:32 AM
Edited Date/Time: 1/5/2020 7:34 AM

By the way, Zip Ty make some aluminium Peg extensions for the KTM pegs, if you want near floor boards to put your feet on.

They make them 125mm long, from the centre of the pivot bolt to the outside of the Peg, and 86.5mm wide, front to back. 32mm of that, is at the back of the 48mm wide KTM Peg.

The 450RR / ADV KTM pegs are 130mm long, from the centre of the pivot bolt, and are 55mm wide (that extra 7mm width, I think is rearward) , and, somewhere around 8 to 10mm lower.

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1/5/2020 3:54 PM

Sounds like a rewarding and exhausting career! Knock on wood I wont need anything more for these pegs unless I chop and reweld them, but thanks for all the info.

I made a little more progress on the pins. It is hard to find time these days.

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1/9/2020 12:48 AM

I think I have a fresh new silencer for that bike.
I also have a red tank in pretty good condition
Email me if you need either
64maxpower@gmail.com
A rear hub and new sprocket too

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1/11/2020 10:24 AM

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1/24/2020 8:52 AM

Progress has come to a halt. I've been sick, its been snowy/single digit temperatures, and I'm out of Argon/Co2 for the welder. Once I get a new bottle I'll be able to repair the broken upper engine mount on the frame and continue on the foot peg mounts. And then I'll be able to take it all in for powdercoating and focus on assembling a roller again.

At least in the downtime I've been able to give some careful thought about the color options for the frame/swinger. I was really considering a metal plated finish, but in the end I'm going with just red and white powdercoat. I realize blue is the OEM look, but I can't stand it. There isn't one drop of blue on the entire bike and it looks awkward to bomb out the frame and swinger in blue paint.

I like the red/white/blue "Made in USA" theme, but the blue needed to be worked in much more thoughtfully IMO. I am also happy to see that the new Acerbis NOST fenders no longer feature the "Acerbis" text boldly printed into the fender, however the fenders look naked without some kind of emblems. I really liked what Yamaha did in 1992 with the rear fender on the YZ's so I took a cue from that bike. I'm going to have a rear fender graphic made to try and incorporate the red/white/blue theme and also give some designation to engine size which was also missing on the original model. And I want it to look era specific, so something basic like in the pic below. Here is the OEM vs. what I'm going to shoot for:

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1/24/2020 8:37 PM

Stickers on the front fender to match the Rear ones you've mocked up would work in well.

The Big ATK on the tank looks great

But, perhaps a Blue seat cover. It seems too much red with it as Red, and the Frame and Tank, as well. A bit too Old XR like. But, then again, I like the blue frame........

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1/24/2020 9:12 PM

I was thinking the same on the front fender but it was looking a bit too much. I think an "ATK powered by Rotax" will fit nicely on the front number plate or tip of the front fender.

Im done with the blue frame! What do you think of all white swinger/frame?

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