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Old 03-23-2014, 10:30 AM   #1
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
A Rally Twin of my own

I learned of the Weber Rally Twin via this thread around 4 years ago. It was stunning how much those bike were exactly what I thought I wanted. Since then, I've acquired lots of parts - to be explained later - and even started an actual build in the spring of 2012, which was taken apart and put back in the shed - also to be explained later.

However, the dream has never died, but has continued to burn ever hotter within my enfeebled brain. And finally, the project's time has finally come. With the help of an actual fabricator this time, the frame is coming together. This is where things stand as of last night:
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Old 03-23-2014, 10:51 AM   #2
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
By August 2010 I had tracked down two EX500's, one wrecked, the other, well, neglected. Plus I had two YZ426 frames, one with forks and rear suspension, and lots of other WR400/426 pieces from when I had those bikes (plated!) Then, in August 2010, I had an accident that slowed me down a lot, but gave me a lot of time to figure out how to make the project happen. To make this build happen, everything had to start out on the cheap - I don't have a huge reserve of funds.
First was the jig. The difference in wheelbase between a YZ426 and the RallyTwin is 4 inches, so I had to figure out a cheap way to accurately spread the frame 4 inches while retaining alignment and headtube angle. I tracked down a 4x4 plate of 1/2 steel (free!) for the table to build the jig on. I came across some strut channel to use as my "tracks" to run my trolleys on.

This is was to be the donor/reference frame from the EX500

Here's the YZ426 frame aligned on my jig, ready to add the braces that will allow me to cut the frame up, separate the halves, add 4 inches to the wheelbase, and retain the headtube angle

This is the trolley

There's one for the front, one for the back. You can see the tracks. They're bolted down and as exactly parallel as they can possibly be. The trolleys fit real snugly with no twist, and slide front to back requiring moderate pressure to do so. I spent many hours getting the table and tracks and trolleys super-level so I could reference plumb and perpendicular off the table and tracks and trolleys in a repeatable fashion.

I spent lots of hours finally getting the frame exactly centered on the jig and plumb as well. The way I approached part of that was by attaching some legs in the form of 3/8 bolts to the bottom of the frame so I could turn them in and out and affect tilt fore and aft and side to side.

The edge of my drywall t-square plus two more framing squares was what I set up to reference off of for centerline

I set up a plumb-bob that dropped out of the steer tube of the forks

The rear axle was centered by measuring equidistant between the ends of the swingarm to the centerline edge of the jig

Finally, it was all perfect and I started welding pieces of scrap tubing (I'd scrounged for free) to brace up the frame.

To the headtube I tacked vertically a 1-1/2 piece of boxtube with one side cut out. Then, I tacked a 2x2 piece horizontally to that. That's what the struts were welded to, in addition to the front trolley

Here's the front end jigged up without the forks in it anymore

The rear section of the YZ426 frame that the suspension and footpegs attach to is all that's getting reused from that frame. I tacked struts from the rear trolley to it, top and bottom.

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Old 03-23-2014, 11:06 AM   #3
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
The pics I'm showing here are all from the aborted build from the spring of 2012. My motivation for that build was to have another dualsport machine (in addition to my plated XR650R) for a 10-day trip in SE Oregon and Northern Nevada I had planned for June 2012 with an old riding buddy, plus the guy who's doing the actual fab work for me on the newly resurrected build. I had the time to make it happen, plus the $. But apparently not the know-how. You'll see that later on.

In the meantime, I think its worthwhile to show all the steps that have gotten the build to where the pic on the first post describes.

I had cut the downtubes out of the EX500 frame, and the top tube and down tubes out of the YZ426 frame. I took the frames outside to cut them all apart and keep the metal mess outside. I used nothing fancier than a sawzall and a hacksaw.

This one shows the EX frame tubes adjacent to the YZ frame before the YZ got cut up. The YZ is supposed to be 4" longer when its stretched to accomodate the EX engine.

YZ frame cut out.

YZ frame headtube and rear section back on the table and bolted down. I had noted the distance between the trolleys prior to removing them from the jig, in preparation for separating them an additional 4" to match the Weber Rally Twin wheelbase specs.

And with the rear section slid back another 4", and the EX downtubes set within to get an idea of whether my idea of marrying these 3 pieces will work

That pic sure made it seem like this wasn't going to be too tough. At that point, I was still ignorant (as I usually am) to the actual fitment issues that were to come - and seriously derail the project.

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Old 03-23-2014, 11:14 AM   #4
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Joined: Aug 2005
Location: Turning expensive metal into scrap
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Cool start, keep it rolling and don't stop and lose momentum
We're not out here to rough it. We're here to smooth it. Things are rough enough in town.

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Old 03-24-2014, 09:35 AM   #5
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Joined: Dec 2009
Location: Cape Town
Oddometer: 326
Very interesting, will follow along as you progress with this project.
1998 KLR 680C; to many mods to list.
2007 BMW 1200GSA.
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Old 03-24-2014, 02:17 PM   #6
Joined: Sep 2005
Location: South Salem, NY
Oddometer: 2,616
Very cool!!!

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Old 03-25-2014, 10:02 PM   #7
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
Now its time to show everyone how it was so nice to make progress, only to fall flat upon my face.

Remember, this is from two years ago...

I finally had the engine sitting roughly where it belongs. Its around 1/8 to 3/16 high, left to right is pretty close, front-to-back still needs lots of tweaking.
There's a length of welding wire in place to indicate the bottom of the 2" box tube top tube I'll be using.

This shows the space I've got to work with to build a plenum, or whatever its called, between the YZ airbox and the EX carbs. Ironically, the YZ airhorn fits the EX carbs exactly. I've decided to not run pod filters because they just end up getting too damned plugged up in dusty conditions. The Webers made some sort of airbox in their totally custom frame that, apparently, did not have this problem.

A major hitch in the plan finally showed itself, and I should have realized it was going to be a problem well before I got to this point.
I had a 6.6 gallon KTM RFS tank, and had intended to use it, but I discovered that it would not fit around the engine. I tried my super-tanker XR650R tank also, and same problem. They're both too narrow at the mid -points back to fit down over the wide EX500 engine's head. What an obvious problem!
I wanted to avoid using the KLR tank like the Webers did. But, I want the 6.1 gallons it carries, and frankly, I don't think there's likely a different 6+ gallon tank made for any bike, plastic or steel, that would fit down over the width of the EX500 engine. IMS KLR650 6.6 gallon tank it will be.

Its apparent why the Webers' frame ended up being the way it is. I shouldn't have doubted them.
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Old 03-25-2014, 10:09 PM   #8
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
Three weeks later, I finally had made some real progress again.

It was very difficult to get the engine aligned with the swingarm pivot, which is what I’m referencing to ensure the countershaft sprocket is in the same plane as the rear sprocket. That is what really took all the time on this project since the last batch of pics. I hadn’t been working on it continuously, but I’m sure I had dozens of hours into just the rear engine mounts. Astute observers will see why it all had to come apart.

Here’s what I had done:
Rear engine mounts

Left side

Right side

Top view

After getting that done (well, mostly, there was some touch up work to do) it was time to figure out how to get the downtubes and bottom tubes connected to the headtube. That's when I realized that there was going to be some major interference between the radiator and fender. By around 2-1/2 inches. Its pretty stupid that I had JUST THEN realized that. I was in a pretty big funk as I couldn't see how I was going to solve it. After a lunch break, the solution occurred to me: Cut things apart.

Here's a side view with the rad somewhat mocked into place

I chopped the downtubes off right below the rad mounts. Elevated them about 3 inches. Moved them back about 2-1/2 inches. And now, the rad clears the fender. By about 1/4 inch

Here's the cut I made, and more or less where the frame will continue down to the bottom tubes, through the left side engine mount.

The additional tube tacked in there is just to help me mock up the position.
Also, the right side won't be so easy. There's engine in the way, so there would have to be a go-around created (didn't take pic, but I recall the problem).

Here's the top tube, viewed from the back of the bike

This pic shows a wire where the bottom of the headtube "brace" will go in, and the downtubes will attach

Looking at the Weber's frame, you can see how the downtube is set back a bit from the bottom of the headtube. Noticing that is what gave me the solution to my rad clearance problem

Here's a front view with the rad mocked into place
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Old 03-25-2014, 10:20 PM   #9
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
And then it hit me. I had not accounted for the upward movement of the chain. This pic shows the complete interference quite well.

By now I had made 3 serious design errors.
1. Tank interference.
2. Rear engine mount design, interferes with the chain.
3. The radiator. I had not considered that it actually needed room in there somewhere...

I was, and am, highly embarrassed about all that. I decided then and there that the whole project needed more thought, and time than I had available to have the bike finished and dependable for my buddy to ride on our planned 10-day trip in SE Oregon and Northern Nevada.

So, I cut all but the bottom right engine mount tab off (would need that in the future, for it was absolutely correct for placement of the engine left-right and up-down), then stuck the whole mess in the shed.

I used the next 1.5 months to acquire another XR650R (got it from another inmate, who lives near me) and set it up like the one I already had. After that trip, I sold it off and recouped my investment.

And now, the project is as depicted in the first pic.
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Old 03-25-2014, 10:36 PM   #10
oregonlmd OP
Dirt,street,its all good.
Joined: Nov 2008
Location: Western Oregon
Oddometer: 250
It will be another 2 weeks before I can make more progress on it. The fabricator is a busy guy and he's fitting this in where he has a hole in his schedule. He will get the main part of the frame welded together, as he and I design solutions to fitment issues. His experience and skill will shortcut the stupid mistakes I made previously.

Here's the framework for the design:

IMS 6.6 gallon Natural KLR650 tank.
08+ KLR650 seat, subframe, airbox, rear fender and inner fender, sidepanels. All that is done, all I have to do is source from wrecking yards via ebay.
Custom plenum (or whatever its called) between the airhorn from the airbox and the carbs.
Exhaust will be a 2-into-1, using stock headpipes, collected behind the right rear of the oil pan, then sweeping up behind the frame and rear brake master, aside the swingarm, then back, with the muffler mounted in the stock KLR location. I'll be using a 2006 KTM525EXC muffler to start with.
Lights will be just the same sort of stuff I had on my XR650R. Basic basic basic. I'd like to add the 08+ KLR fairing for street trips, but that's budget $$ down the road.
Wheels are the stock 21/18 that came on the WR/YZ, though with black excel rims, HD spokes, and a Talon rear hub. Front brake will be upgraded to an oversize rotor, to deal with the additional 100 pounds this thing will be over what a WR426 weighed. Again, when future $$ become available, I'll get a set of SUMO wheels for street tours.
I will have the suspension re-valved to deal with the new-found weight, plus add in obviously much heavier springs to get the sag correct. I weigh 180 in street clothes. I think that if the bike is valved to deal with a 300lb rider in dirt-riding gear, it'll be about right for dual sport duty. I'd like it to be slightly on the soft side, but with excellent control over bottoming.

The goal is to be able to ride this thing by mid summer. We'll see how that plays out...
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Old 03-26-2014, 04:56 AM   #11
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Joined: Aug 2005
Location: Turning expensive metal into scrap
Oddometer: 5,814
Couple notes as we have run into many of the same issues. Try to get the pivot points for the swingarm and countershaft as close as possible on the side view. Too far apart and you will get lots of chain droop, which I am working through now.

I had some radiator clearance before and i just made some spacers for the back bolts to pull it away from the rad. Easy.

My last bit of advice is resist the urge to use the parts you have, especially if you have to force them to fit, in order to sve money. I can't tell you the number of times I designed a component to utilize parts I had laying around when it was obvious it wasn't going to work well. But being frugal and stubborn I would spend hours forcing the part to work only to discover down the road that it was a huge mistake. That's jumping over dollars to pick up dimes.

Great choice on not going pod filters, I have them on my fz1 and the fueling sucks at cruise when it's windy out. My ninja I have as much stock as possible relating to the engine and it's a happy camper.

Def go bigger brake on the front and you might want to look into a super moto setup. I have one on mine and my bike stops great with a single rotor. The stock master cylinder might not be up to the task of hauling that bike down from sped. All depends on how and where you ride I guess.
We're not out here to rough it. We're here to smooth it. Things are rough enough in town.

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Old 03-26-2014, 05:08 AM   #12
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Joined: Feb 2007
Location: Mountains of Central Florida:)
Oddometer: 5,362
Looks interesting!
ADVmonster...BLOG....Dirt Ninja Build...TAT 08
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Old 03-26-2014, 11:06 AM   #13
Joined: Dec 2012
Location: North Georgia
Oddometer: 220
This will be nice when finished. Keep the regular reports coming.
Scubawerx--Underwater Search Salvage and Recovery
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Old 03-26-2014, 11:29 AM   #14
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Joined: Jul 2008
Location: Denver
Oddometer: 492
I love it, I cannot wait to see how this progresses!!!!

Keep in mind Wes and Wayne spent years working on their masterpieces, 1,000's and 1,000's of hours and many more dollars than that. I think Wes said there are around 750 individually designed and cut pieces welded together in just their alloy frame alone. By the time they designed all the brackets and mounts.

For every problem solved, two more will pop up. You have nothing to be ashamed of as far as not foreseeing problems, that has just begun.

Sailah has some great wisdom; keep up the momentum. It is just like eating an elephant, there is only one way to do it; one bite at a time. Keep thinking about the symphony, but focus on one thing, one bite at a time. And if you get stumped, move on to something else and come back. There is also a lot of wisdom in just getting the right components to start with. I wasted quite a bit of time, effort, and money trying to save a few bucks, and costing myself in the end.

Can't wait to see this move along, one bite at a time!



P.S. - I have a KLR side-cover that I haven't gotten around to trying to sell yet. PM me if your are interested.
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Then post a picture of the sticker on your OHV and post it on COHVCO's Facebook page to show your support,

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Old 03-26-2014, 05:34 PM   #15
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Joined: Jun 2010
Location: South Africa
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Very interesting and challenging build.

With the drive sprocket aligned with the rear does the engine sit central to the frame or a little to the right?
2007 990 Adventure
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