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Old 11-14-2010, 01:21 PM   #1
DaBit OP
Gnarly Adventurer
Joined: Nov 2008
Location: Netherlands
Oddometer: 345
Yet another SV650->Adventure build

When the LC4 Adv was sick I needed another bike to ride on. The intention was to get a simple lower-priced roadbike which I could just ride, and sell for the price I got it for (or at least not much less) once done with the LC4.

Well, it just happened that a guy I knew was selling his '99 SV650S. I knew he was the kind of guy that sleeps badly when there is a speck of dirt on his bike, so no problem with lack of mainenance etcetera. I visited him, saw a bike in front of the house which looked like it just rolled out of the showroom, did a test drive, and arranged to pickup the bike and the paper work.

The bike right after I drove it home

Well, after several 1000's of kilometers, I decided I like the weight of the bike and the engine very much. It's torquey, smooth, has a wide useable RPM range, and offers plenty of power. However, I absolutely hate the suspension (must brake for a speed bump, yech!) and seating position.

After seeing the bike 'Russ S' built (absolutely one of the greatest builds ever), I decided to give it a try also. Maybe it is a bridge too far, maybe it isn't. We'll see. I started wrenching only a few years ago, I lack metalworking skills, I have no artistic genes at all, no clue what to do with angles that are not 45- or 90 degrees let alone curvy things, and my main tools are a hacksaw, a hammer, and a cordless drill. Oh, and a welder.

The target: not an hardcore offroad bike, but an adventure bike. One I could jump on, ride 1000km over the blacktop at 140km/h to an interesting and sunny place on earth, and do some exploring over the smallest and worst roads ever, or no road at all. That's my idea of fun. The LC4 comes close, it it only wasn't such a vibrator. The LC8 comes close, but those are expensive and generally too much. Too much weight, too much fuel useage, too much power.
I want that bike to weight less than 200kg. Not 'dry', but less than 200kg 'ready to ride', thus loaded with fuel for 350km range, skid plate, GPS mount, tools, softluggage rack, etcetera. My LC4 adventure weights 184kg once farkled up like that. Also, I want a 21" front, and preferrably an 18" rear, and something like 200-250mm of suspension travel.

And I want most of the weight to reside low. kilos are only that, kilos. But it makes a lot of difference if they reside under the bike, or far back and high up. Thus, the fuel tank on to has to move, battery will move out of the sub frame, etcetera.

Oh yeah, and the build has to be fairly cheap; the other family members have to eat too.

So, how does one start? The SV has an exhaust pipe underneath the engine and therefore it's impossible to jack up the bike with an hydraulic bike lift. So, one starts with the skid plate and relocation of the footsteps. If either one of these tasks proves to be too difficult, going further makes no sense.

So, skid plate. Take that literally; even with increased suspension travel the bike will lack ground clearance. I could have done what everybody does: make one out of aluminium. But I have a hard time welding aluminium, and I think aluminium is not a very good material for a skid plate. It is fairly heavy, it is expensive, it doesn't slide well, it corrodes easily, it dents, dirt sticks well to it, it reflects a lot of noise back to the rider, etcetera.

Plastics like HDPE or even better UHMWPE seem to be a much more suitable material. Slippery, tough, good abrasion resistance, light. So I decided to go for a metal frame with a plastic skid plate.

OK, decision made. Then I started walking around the bike to find mounting spots and a possible new location for the footsteps. A piece of steel strip here, some cardboard there, figuring out what to do.

Tinkering around with some cardboard, see how it ends up (and this sucks)

Possible new footstep location?

It soon became clear that I needed to weld plastic sooner or later (I also intend to use HDPE for the underseat fuel tank). Had to play with that too, but I had no plastic welder. A second hand one was too expensive, and I could not find cheap Chinese copies. So I decided to make one myself from an old paint stripper with broken fan. Replaced the fan with an attachment for compressed air, and made it possible to adjust power to the heater. This allows me to produce dry air at a stable temperature of 300 degrees C: perfect for welding HDPE.

First test of the plastic welder

First result with a strip of HDPE I sawed off as a welding rod:

OK, have to exercise a bit more, but this weld is already very strong. Way good enough for the skid plate. Have to order a few welding rods though.

So, I moved on with the metal work. I decided to make a mockup out of steel strip since measuring is quite difficult.

This 'bunch of metal strips' evolved more and more:

So in the end I decided to reinforce the frame, and keep it. It will weigh a bit more than I'd like, but that weight is mounted low. It will look like sh*t, but nobody will see it.

The footsteps. All that 4mm steel should easily be able to carry the footsteps. so, I got myself a set of cheap pegs, and made the mounts.

Test mount with 4mm bolts:

OK, seems to work if I replace the 4mm bolts with 8mm Allen bolts. Let's add more metal to the frame, and construct the other side. Aligning the steps is important, so I set up my cheapo cross-laser:

At last I drilled the peg-bracket mounting holes, welded in nuts, drilled mounting holes for HDPE skid plate and welded nuts there too. This is the current state

I think I should give it some anti-rust protection, and mount it. Then I can jack up the bike. Next will be the foot-operated controls, I suppose. Have to figure out how to do that.

To be continued....
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