A DIY custom motorcycle; it’s in your blood to build. But with so many styles, and catalogues full of options and accessories, where to even begin if it’s your first-time project?
So you want to build a custom motorcycle yourself. Or at least some of it yourself. Good thinking. There is great satisfaction in saying “I did that.” In my opinion, far more than saying, “I bought that.” But, as Dirty Harry once said, “a man’s got to know his limitations.”
True, there is our own comfort level which we should push, at least a little. And it never hurts to have capable friends. But while confidence is good, overconfidence is not.
I had a life-changing moment several years ago while eavesdropping on an interview with the Great Roger Goldammer, Canada’s own three-time world champion of custom bike building. He surprised me when he said there were things he did not know how to do and sometimes had to take time out to learn a skill he needed to finish a certain project.
I thought, hey it’s okay to learn as you go. For me this was huge. It won’t be like on TV … this will take a while.
As you start big choices, and lots of them, have to be made up front.
1. Buy a good used (or even new) donor bike and modify it. This is a favourite and smart choice. This option takes care of registration issues and gives a good basic proven design that you know will work if not changed too radically. It can also be very economical as well.
2. Buy a “kit” bike. This can be a good option if there is a design that “speaks” to you. The design work has been done and proven, if it’s a legitimate company. This can be an exercise in assembly but remember nothing ever goes 100 per cent smooth unless you are way luckier than me. Usually options are offered which help the “unique” aspect. Be careful, there are untrustworthy characters selling “rollers” of questionable worth. Do some research. Also check online forums.
3. Buy a frame and have at it. Here you are limited only by the basic design, almost everything is up to you. The frame will dictate maximum tire size, rake, solid- or rubber-mount and of course suspension or rigid construction. Nothing looks cooler than a rigid, and they work great on smooth roads. But few things hurt more than back injuries. If you live where the roads are rough or you have back issues or are getting up in age, think twice. I build with suspensions because I have a bad back, am getting old and travel wherever. I also like the challenge of setting up the suspension to work well. You can travel faster on a bumpy road if both wheels stay in contact with it.
This is important—make sure it’s an “approved” frame. You could spend lots of money to find out certain brands of frame cannot be registered. Also be wary of used frames. If it’s been written off (accident) it may be impossible to get it re-registered.
4. Build your own frame. (Not for beginners!) You must be a very good welder or have the services of one to weld together the pieces. This is what I have done in the past. Lucky for me I know some awesome welders. Your life and possibly the lives of others depend on the welds—don’t chance it if you are not a pro.
While building your own frame opens up almost unlimited choices, the laws of physics remain the same: the frame needs to be arrow strait (a jig may be required) and you must understand rake and trail.
5. Rear suspension can be challenging, there are lots of options. Some don’t work well with others. One reason so many builders go the rigid route is that rear suspension technical problems don’t exist.
6. You choose the rake. In general more degrees mean more straight-line stability, whereas fewer degrees will give sharper handling and quicker turning. Of course if you go too far either way the bike may not want to turn or it may be the other extreme in which it will steer like a shopping cart and be very unstable. Personally, I like around 31 degrees on a V-Twin.
7. Trail is also important and must work with the rake—sportbikes have less than choppers. Like rake, too much or too little trail will cause major handling issues. Ever notice a long rocker on a springer? This is a way of adjusting trail. When building a custom remember it is an art form, the “stance” is important. Visualization may dictate small changes.
8. The wheelbase will dictate the overall proportion and size of the bike. Short wheelbases usually turn sharper (the handling of some bobbers is awesome).
9. Front suspension is also a choice and quality is all over the map. Conventional or upside down tube style forks are normally safe and I think the best bet. Some would say springers are the way to go, I have tried some that work really well.
The good ones have a damping shock as seen on the Harley-made units. Without the damper, the front wheel can bounce out of control. Back in the day, my friend Reggie found out the hard way. He lost his bouncing front end on some railway tracks, hit a parked car, and removed his “coffin tank” with his private parts. After a hospital stay he was ok and even went on to have children. However he has not ridden much since.
Last year I heard of an aftermarket springer actually breaking while just riding down the road, causing major damage to a show bike.
10. Other considerations include the engine. One choice is a used metric. It’s by far the least expensive and can be lots of fun. I would suggest a large displacement engine.
Another choice, and by far the most popular, is the American V-Twin. There are tons of parts available with displacements up to 145 cubic inches. last time I looked the 80-inch engines were very popular for reliability. The big engines bring expensive upgrades and in some cases reliability and fitment problems.
By Rich Burgess, Canadian Biker Issue #272