Throttle Junkie Tech- Sportster Hardtail

Article By: Paul Wideman – www.bareknucklechoppers.com

Originally Published In The July 2012 Issue Of Cycle Source Magazine

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It’s no secret that many new motorcycle products are different just for the sake of being different. Over engineering, mated with an active imagination, can sometimes give birth to a less than desirable character. Oftentimes, lack of creativity spawns a new part for your bike, in the form of a ripped-off piece, like so many of Fab Kevin’s innovations that have been copied and shipped from the other side of the world right to your neighbor’s doorstep (We know you’d never do that). And then, like my old man told me years ago, don’t go out of your way to do it different, just do it substantially better. Of course the rip-off course was never an option.

That being said, I will explain how our hardtails came about. Yes, they have been offered in one form or another for decades. Even though the K and XL models preceded the Big Twin in a rear suspension offering, chopper guys still couldn’t help but step back in time and hardtail that Sporty. We’ve all seen a thousand versions if we’ve seen one: the classic bolt-on that is actually welded on; the weld-on that is made of schedule 40 pipe and welded by a third grader. But there have also been some really good ones. Arlen and the boys did a million hop-ups to Sportsters, and so many of them looked perfect.

We had been inundated with requests for a quality hardtail for a few years, but due to other obligations had not gotten around to it until early this year. Each time we would have to bring the customer’s frame in and do the transformation in-house. Now we have a kit, and I think we worked a great deal of the bugs out that plagued so many of the others out there, and of course they are made of only the finest U.S. DOM tubing, mild steel, and they are professionally TIG welded. All of the hardware is stainless steel, also made right here in our humble shop.

We never cared for the loop rear section design for two reasons: the subsequent butt weld to the cradle is suspect from a stress-flow perspective and it looks like an afterthought. We wanted the resulting chassis to look as if it came straight from Milwaukee with no suspension, just a smooth flow all the way around. Also, while talking with Wildman about the idea over the last few years, he always brought up the fact that so many Sportsters and Sportster builds look like the rider is riding way up high, or in some cases, the drop seat of the hardtail kit looks cartoonish and unnatural. We set out to lower the ride height without delving into a true drop seat. Follow along and see how we did. Throughout the rest of 2012 I will be transforming my mom’s recently retired 2001 XL into a killer little chop. This should be cheap, fun, and interesting.

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We built our jig out of a cherry mid ‘90s Sporty that I bought online. Rather than tie up one of our other jigs for this, we can move this one around and store it when not used. Using the OEM frame as a base assures we will have perfect alignment. Here Russ is loading up the first parts.

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We usually do at least 5-10 of these at a time, so Russ will take a day and prep all of the material. The axle plates are water jetted and then the axle is milled. The rear motor mount is machined in-house.

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While making the cradle, there is a different offset from the left side to the right due to chain/belt clearance. Here, Russ checks to be sure his bends result in the perfect offset.

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Now you can see the additional offset to the right side to allow for belt clearance.

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After the rails are bent and double checked for proper fitment, I’ll weld a cap on the end of the tubes for a more finished look.

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Next, while Russ was fitting the backbone, I ground out the welds and polished them down with a DA.

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Russ jumped ahead and got to work on the short cross member that the seat post will rest on.

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Our first couple runs of the hardtail kit used a 7” radius bend for the backbone/ seat post, but it made for a tight squeeze between the engine and oil tank. We called Mittler Brothers and asked them to make us a much tighter shoe to make a lot more clearance.

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After tacking the seat post and rear motor mount, we got started on the top rails.

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This is where a good fixture really comes in handy. Russ made short work of the seat rails.

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A quick seat bar and we are about ready for my favorite part…

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…finish welding!

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Once out of the jig, we use this handy little fixture to locate and hold the axle adjusters for welding.

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And we’re done! This pic gives you a good idea what the slightly lower seat height does. It’s barely noticeable, but it gets you more in the bike, rather than on the bike. That’s it for this month. In the next installment we will have the new project hardtailed and we will begin setting up the rest of the chassis. Until then, FTW – Paul

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