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forks and valves... WTF?
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Discussion Starter · #1 ·
Here's a riddle to start off with... what has 54" wheel base, 21 degree rake, makes 50hp on a good day, and has accumulated boxes of road racing trophies?



Answer is an AK-1.


Here is a brief history for those who don't know what an AK-1 is. Back in the late 90s I got this idea that I wanted to get into the motorcycle business selling exotic kit-motorcycles. This business model had worked two decades earlier for Bimota.

The owner of a local motorcycle salvage had been sending me numerous EX500 to modify for his customers who wanted to get into road racing on the cheap. I did lots for fork swaps, rear wheel swaps, custom brake hangers, and stuff like that. The EX500s were popular little race bike at the time and salvage yards were full of potential donors. I just needed to design and build the right frame that everything would easily bolt onto and I'd have my kit. Thus became the AK-1 (A= A-N-D Vehicles, name of my new company; K=Kawasaki for the engine being used; 1= first model).

Over the winter of 2000-2001 two prototype frames were built. One of those frames was built into a complete bike.

[/url]AK1.p4 by andbike, on Flickr[/IMG]

[/url]DSCN1220 by andbike, on Flickr[/IMG]

Here is how that first bike looked at the International Motorcycle Show in Long Beach, CA, December 2000.

[/url]andbike by andbike, on Flickr[/IMG]

Another photo taken a week after the LongBeach show (I still had hair back then)

[/url]33108_IqWtFjliUFn74XGzoJ3VsXNoK by andbike, on Flickr[/IMG]
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #2 ·
The plan was to follow the two prototype frames with a small batch of production frames that would be available for sale. To promote the business I sponsored two riders (Tom Dorsey and Shawn Reilly) with AFM (local racing club). By the first race of the 2001 season the production frames were close to being finished, but not in time for the race at Button Willow Raceway. We decided that Shawn and Tom would take turns riding the prototype in practice on Saturday, then on Sunday one would race in 500cc twins class, while the other would race in the super fast Formula 2 class.

Because of a very odd chain of events we would sit out the 500 twins class that day, which ultimately cost us the championship at the end of the year... but this thread isn't about the racing stories although there are some good ones. This thread is about that first prototype bike which is still sitting in my garage 15 years later.

One valuable bit of design feed back I got from my riders that first weekend was that the bike was too long, or at least the seat to bar distance was too long. As it turns out, the racer pitted next to us at Button Willow had two Yamaha R6s. I kept looking at the R6s, then at my prototype, and so on. Turns out the R6 is the seat and tail used on the prototype. But in trying to keep as much of the EX500 donor bike, the prototype was designed to use the EX500 tank with a fiberglass piece that fits between the tank and the R6 seat the mate them together. This made for a very long reach to the bars.

The following week I purchased two R6 tanks on eBay and re-resigned the rear sub-frame to accommodate this change. The end result was a 2" reduction in the bar to seat distance... and the R6 tank matched VERY well with the EX500 fairing. Sometimes you just get lucky. So with the new sub-frames designed, the race bike were completed and all was good... and the trophy collection began to grow:party-smiley:

For some reason I decided to use red accent color on the race bikes...

[/url]DSCN0081 by andbike, on Flickr[/IMG]


[/url]DSCN0080 by andbike, on Flickr[/IMG]

[/url]DSCN0106 by andbike, on Flickr[/IMG]

[/url]DSCN0089 by andbike, on Flickr[/IMG]

Tom at Sonoma (Sears Point) Raceway...

[/url]AK-1 race_2 by andbike, on Flickr[/IMG]

Shawn at Sonoma (Sears Point) Raceway...

[/url]AK-1 race_3 by andbike, on Flickr[/IMG]
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #3 ·
That first year of racing went very well and the collection of trophies got very large. It was fun watch Tom and Shawn on my bikes. Tom's background was with 250 Production bikes and this his strength was in corner speed and very very smooth lines around the track. Shawn's background was complete opposite as he was also racing a 150hp GSXR in several of the superbike classes. His style is to be more physical with the bike. Both riders were equally fast on teh AK-1s, so depending on which track we were at one would have a slight advantage over the other. By the end of the season we had a firm hold on second and third place in points for the 500cc Twins class with Tom slightly ahead of Shawn. Our nemesis was a bike known as "The Gibson". It was a one-off, trellis framed, EX500 powered bike, owned and ridden by Kevin Smith. We were getting closer and closer to Kevin in points as the season went on, but because we were playing catch up having missed the first race of the season, Kevin would eventually take the championship that year.

These are the only photos I could find of The Gibson bike (built by two brothers, last name Gibson)...

[/url]ex500gg2 by andbike, on Flickr[/IMG]

[/url]ex500gg1 by andbike, on Flickr[/IMG]


In addition to AFM 500cc Twins racing, the bikes were also raced in several AHRMA events in light weight twins against SV650s. We never won any of those races, but usually managed to get on the podium for a second or third place finish. We also did something very unusual that year, Tom and Shawn talked me into let them take the bikes to Laguna Seca for World Super Bike! Of course we didn't race in World Superbike race, but on Thursday of the four-day event was the AMA ProThunder race which we did race in. This was a class dominated by 1200cc Buells and 748 Ducatis. The class also has a 600cc minimum displacement rule! The idea we had was be the only team to ever race stock EX500 powered bikes in the class. Our goal was to finish better than last place. We lied about the engine size telling the tech inspectors that the bikes had 612cc big bore kits installed which they didn't.:fu: :LolLolLolLol: One bike was officially a DNF with a mechanical (sand in the carb) and the other bike finished ahead of two or three other riders. It was great fun.


In 2002 I handed one of the AK-1s over to Zoran Vujasinovic and he won a nice big championship trophy in AFM 500cc Twins Class. Zoran has deep history racing SV650s. His company TWF Racing makes lots of racing accessories and does race tuning. Here is his website... http://www.twfracing.com/index.html
 

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This sounds awesome man, but none of your pics are working for me


Sent from my iPhone using Tapatalk
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #5 ·
Now getting to the project... the original prototype bike is no longer all nice a shinny like it was 15 years ago (see pictures in first post). A few years ago lights were added which required welding extra tabs and brackets to the rear sub-frame. It was never painted after those changes and has some rust issues now. The gas tank decided to start leaking after a few years. And the bike has spent most of the time in the back of my garage getting other motorcycles bumped into it and random stuff dropped on it.

So I've decided that its finally time to pull it out of the garage and do a complete re-fresh, including building a new sub-frame and fitting an R6 tank as was done with the production bikes.

So I guess this officially begins my new build thread. First, is to remove the old grubby sub-frame. (sorry, didn't get any pictures before starting the dis-assembly process). You can see its pretty shitty under the bodywork...

[/url]20160528_122826 by andbike, on Flickr[/IMG]

[/url]20160528_122723 by andbike, on Flickr[/IMG]

[/url]20160611_123123 by andbike, on Flickr[/IMG]

Next step is to strip down to the bare frame since the R6 tank conversion requires two new tabs welded to the frame and then it will be sent out for powder coating once the new sub-frame is made. Chassis with body work removed...

[/url]20160625_132524 by andbike, on Flickr[/IMG]



Here is how it looks above the engine with wires and coolant hoses crammed in place...

[/url]20160625_133117 by andbike, on Flickr[/IMG]


few more items removed....

[/url]20160625_143125 by andbike, on Flickr[/IMG]

[/url]20160625_143150 by andbike, on Flickr[/IMG]

In addition to being just a much better frame than the stock EX frame, I also like how easy it is to drop the engine out. Remove three bolts, and out it comes. So simple when nothing is in the way...

[/url]20160625_145104 by andbike, on Flickr[/IMG]

Finally down to the rolling chassis and ready for some clean up and new fabrication...

[/url]20160625_145538 by andbike, on Flickr[/IMG]


[/url]20160625_145431 by andbike, on Flickr[/IMG]
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #6 ·
This sounds awesome man, but none of your pics are working for me


Sent from my iPhone using Tapatalk
Sorry about that, but not sure what to tell you. I use Flickr for my photo host and been doing it that way for a few years now without issues. Maybe someone else can share some knowledge as I am much better at metal fab than web / computer stuff.

cheers.
 
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ah I can see them on my computer but not on my phone. weird. bike looks awesome man,I love the frame, I'm definitely going to be watching this.
 

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forks and valves... WTF?
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Discussion Starter · #10 ·
Awesome stuff! Any info on that swing arm front suspension bike in the last picture of the first post?
Not a build thread, but more of a clean-up thread...

http://www.customfighters.com/forums/showthread.php?t=62571

Also a few online articles recently, even though its an old project... started building it in 1990. Rode it for the first time around 1997 I think(?) Have done a few re-fresh on the paint over the years.

Sorry but a lot of these articles are going to be repeat photos.

Article in MotoRage (pages 28-30)...

http://motorage.hu/pdf/2016_majus/Default.html


The Biker's Garage...

https://thebikersgarage.wordpress.com/2016/01/03/julian-farnams-forkless-yamaha-rz-350/


This article in Worldwide Bomber Magazine has some good original photos. Note, use up / down arrows to scroll through the article (NOT left / right)...

http://www.worldwidebombermagazine.com/issues/issue8/#/article/16/page/1
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #12 ·
What is the shock from for your linkless rear suspension? What's the spring rate on it?
The short answer is that its a custom shock specifically designed for this bike.

The longer answer is that the original chassis geometry was done using a shock from a Yamaha RZ350, but changed the lower eyelet. When I went to Fox to have them build up a few shocks for me they did a cross reference and found that a Honda 900RR was almost identical (same length and spring rate) and with the proper eyelets and valving better suited to this bike. I believe they also did some internal tweaks to the valving to get an even better match for this application. When Fox stopped making motorcycle shocks for a few years, I then passed along the information to Penske and had them make a few shocks. Supposedly they still keep me in their data base but its been many years since one of these bikes has been built up.

I think the original spring rate was around 600lb/in... or maybe 650lb/in. When Zoran raced the bike I think he went with a stiffer spring, maybe 700lb/in. This is rough guess as I forget the actual numbers but somewhere in that range.

One design feature is the three mounting positions. If you look where the shock mounts to the swingarm you'll notice three sets of mounting holes. They are positioned to produce a +/-10% change in effective spring rate at the axle. On the race bikes we always used the stiffest position, and I'll probably move to the stiffest position on this bike when it goes back together.
 

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CAPTAIN AWESOME®
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The short answer is that its a custom shock specifically designed for this bike.

The longer answer is that the original chassis geometry was done using a shock from a Yamaha RZ350, but changed the lower eyelet. When I went to Fox to have them build up a few shocks for me they did a cross reference and found that a Honda 900RR was almost identical (same length and spring rate) and with the proper eyelets and valving better suited to this bike. I believe they also did some internal tweaks to the valving to get an even better match for this application. When Fox stopped making motorcycle shocks for a few years, I then passed along the information to Penske and had them make a few shocks. Supposedly they still keep me in their data base but its been many years since one of these bikes has been built up.

I think the original spring rate was around 600lb/in... or maybe 650lb/in. When Zoran raced the bike I think he went with a stiffer spring, maybe 700lb/in. This is rough guess as I forget the actual numbers but somewhere in that range.

One design feature is the three mounting positions. If you look where the shock mounts to the swingarm you'll notice three sets of mounting holes. They are positioned to produce a +/-10% change in effective spring rate at the axle. On the race bikes we always used the stiffest position, and I'll probably move to the stiffest position on this bike when it goes back together.

Interesting
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #16 ·
Getting back to the task at hand, need to build a revised (shorter sub-frame). Back in 2001 when I built the first sub-frame for the race bikes, a fixture was then built off of the first sub-frame such that it could be easily replicated. I also made a reference sample of of the main tubes which are sliced-bent-welded. Here is the fixture and the reference tube sample..

[/url]20160515_110158 by andbike, on Flickr[/IMG]

[/url]20160515_110554 by andbike, on Flickr[/IMG]

All tabs and brackets were laser cut in batches for the original builds. I still had a few extras...

[/url]20160515_110527 by andbike, on Flickr[/IMG]

The main structure has a left and right main tube (with the joint in the middle) and diagonal support tubes. Each tube is mitered and sliced at one end with a tab welded in place...

[/url]20160515_122147 by andbike, on Flickr[/IMG]

20160515_122321 by andbike, on Flickr

[/url]20160515_133955 by andbike, on Flickr[/IMG]

the diagonal tubes get fish-mouthed at the opposite ends...

[/url]20160515_133947 by andbike, on Flickr[/IMG]

One the tubes are ready they get mounted into the fixture...

[/url]20160515_125219 by andbike, on Flickr[/IMG]

[/url]20160515_144711 by andbike, on Flickr[/IMG]

Next is to prepare the front seat support. 1" square tube with a bunch of holes...

[/url]20160515_152506 by andbike, on Flickr[/IMG]

[/url]20160515_153644 by andbike, on Flickr[/IMG]

The rear seat support is also a 1" tube, but sliced in half and supported with two short 3/4" tubes...

[/url]20160515_160243 by andbike, on Flickr[/IMG]

[/url]20160515_164052 by andbike, on Flickr[/IMG]

These are then attached to the fixture and welded to the tube structure now connecting the left and right sides. Its starting to look like a sub-frame...

[/url]20160515_171026 by andbike, on Flickr[/IMG]
 

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forks and valves... WTF?
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671 Posts
Discussion Starter · #18 ·
Here are a few more updates on the sub-frame build. The brackets that hold the battery box were laser cut. They are easy to bend into shape, then weld in place...

[/url]20160515_171342 by andbike, on Flickr[/IMG]

I usually design my sheet metal parts with slots where the bends go. This makes bending by hand easier and much more accurate. The metal will naturally bend along the slots...

[/url]20160515_174553 by andbike, on Flickr[/IMG]

Welding in place...

[/url]20160515_182130 by andbike, on Flickr[/IMG]

Next are some brackets to support the rear of the tank and front of the seat...

[/url]20160618_132818 by andbike, on Flickr[/IMG]

Just about finished. I can take the sub-frame out of the fixture and do some check fitting on the bike. The rear bracket is built as a one-off a few years ago back when I added lights to the bike. I simply cut the welds to remove it from the original sub-frame and tacked in place on the new sub-frame...

20160618_133836 by andbike, on Flickr

[/url]20160618_133823 by andbike, on Flickr[/IMG]

On the bike. OH SHIT!!! I never noticed because I've never used the under-tail panel on the race bikes, but it doesn't fit with the shorter sub-frame design. Hummm, now what to do since the under-tail is what the tail light attaches to...

[/url]20160618_153305 by andbike, on Flickr[/IMG]

I decide to make a tab for attaching the tail light without using the under-tail...

[/url]20160618_164343 by andbike, on Flickr[/IMG]

[/url]20160618_171027 by andbike, on Flickr[/IMG]

[/url]20160618_173527 by andbike, on Flickr[/IMG]

Now the tail light can be attached, but kinda naked without the under panel. Oh well. It should look okay once the sub-frame is powder coated in bright yellow...

[/url]20160618_173920 by andbike, on Flickr[/IMG]

One last bracket and the plate and blinkers can be attached...

[/url]20160618_180637 by andbike, on Flickr[/IMG]

Now a check fit with the tank and that wraps up the sub-frame build. Now cant wait to get everything painted and powder coated back to the original yellow and bronze...

[/url]20160618_174339 by andbike, on Flickr[/IMG]


Stay tuned for more...
 

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forks and valves... WTF?
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Discussion Starter · #19 ·
Here's another quick update, but first some back-story. The original machine shop that made the side plates for the mid-frame made the first few plates using the wrong material. For some unexplained reason, they used mic-6 tooling plate rather than 6061-T6. I probably ended up getting those plates for free, but it was many years ago so I forget the details. Anyway, the mic-6 plates ended up on this this bike as it was mostly to be used for shows and not ridden.

Over the years, the bike has fallen over a few times in the shop and the plates have been broken and welded back together where the footpegs mount. Mic-6 also oxidizes much worse than 6061, so the mid-frame looks pretty bad now.

So decided to make a new mid-frame (plus a spare). This time around I've also revised the design so the plates are thicker where the footpeg brackets mount.

Anyway, just got some pictures from the new CNC vendor...

[/url]16. 08. 04 picture-01 for SP15P031-013 by andbike, on Flickr[/IMG]

[/url]16. 08. 04 picture-10 for SP15P031-013 by andbike, on Flickr[/IMG]

Since I'll need new cross tubes I'm turning those myself. Here is one of the large tubes partially machined...

[/url]20160730_162947 by andbike, on Flickr[/IMG]

Okay, that's it for now.
 

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Your work is awesome as always!

Those frame parts remind me of the rear footrest hangers on a JDM CB-1 400.
 
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