because the SV650 has a beautiful torquey ultra-reliable engine, and you can pick up them very cheaply. and i wasn't interested in a wee-strom DL650 because i don't like the look, the detuned engine, the size and the weight. and figured it would be a fun project.
HOW FAR TO GO?
from similar threads, i figured i had the following options...
EASY - just throw some dual purpose tires on the existing rims. guys have done this, but i figured the soft under-dampened front forks on the SV are bad enough on bitumen, let alone a dirt road.
INTERMEDIATE - adapt suitable forks from a dirt bike, dual purpose tyres on the existing rims, convert to single front disc and jack up the rear with shorter dog bones to compensate for the higher front.
FULL ON - adapt the triple clamps and entire front end from a suitable dirt bike, jack up the rear with shorter dog bones and a better rear shock, reroute the exhaust into a rally-style setup, create a subframe to move the footpegs down and forward and mount a bashplate to, remodel the tank and seat etc. possibly go to spoked wheels, or at least a 19 inch front wheel.
i decided to go the intermediate way due to a tight budget and being a bit of a mechanical noob. and the SV will only be doing easy dirt roads so i didn't feel the need to go too far with the suspension.
first, the front forks. there's a handy list of alternative 41mm front forks here
. an advantage of slipping these into the existing triple clamps is you still have your steering lock and existing instrumentation all in place. got hold of a cheap pair of early XT600 forks that slotted in nicely. the springs were way too soft. pulled them apart and found each fork had two springs. i removed the short soft one and replaced with a long spacer. this increased the spring rate on the remaining primary spring and worked very nicely. it was under-dampened too so replaced with 12.5w fork oil which improved things up front.
next a front wheel. i wanted to keep the road wheels as is so i could change over if i felt like it. i had a pair of honda CBR250R wheels lying around. the front had a 310mm disc so i made up a caliper adapter plate to push the caliper out enough for the larger disc. messed around at the local wreckers and eventually found an axle that suited the XT forks, then machined spacers to make everything line up.
i wanted to keep the SV front brake setup intact, so back to the wreckers and came back with the front brake setup and four pot front caliper from a fireblade CBR600, and a single braided brake line. this wound up working really well. the stronger caliper still hauls the SV up very quickly on the single disc but is not overly grabby for dirt roads.
the honda CBR250R rear wheel was an easy fit. i needed 20mm spacers to move the rear disc further out, and just machined wheel spacers to suit. i thought it was important to keep the drive chain completely straight, so left the rear wheel slightly off-center... i knew from motarding days this wouldn't affect the handling at all.
tires? chucked a mitas E07 150/70-17 on the rear. the front was trickier as the CBR250R front wheel is only 2.5 inches wide. i had a trailwing 120/90-17 rear tire lying around and figured i'd start with that... the high profile takes the rolling diameter closer to that of a 19 inch front wheel, and i was hoping the comparatively narrow front rim on the CBR would give the correct tyre profile for cornering.
what else? i bought a generic motard front fender and made a bracket so i could bolt it on to the triple clamps. i machined some one inch spacers for the front bars and rolled them back for a more upright position. any higher than this i would have needed longer cables. i'm quite tall so i grabbed some upholstery foam, black vinyl and a staple gun to build the seat higher. it's just a rough job and may get it done properly if it works out in the long term. a kamel toe was put on the stand so the sidestand won't sink in the dirt. fitted some frame sliders that will at least protect the radiators from stacking on the road, but dubious about how much protection they would offer offroad.
HOW DOES IT HANDLE?
i had concerns about the handling due to putting dirt bike forks into road bike triple clamps, especially with the front axle now sitting in front of the forks. but it seems pretty good so far. it handles more like a dirt bike with a 21 inch front wheel on the road, it's less likely to tip into corners and feels very stable in a straight line. cornering on road actually works better riding it like a dirt bike too, lean the bike but keep the body upright. i still haven't done the dog bones yet to yet the rear end higher so will report back when that is done.
the front suspension is a huge improvement, on or off road. but i wouldn't want to push those 41mm forks too far so would certainly be taking it easy on anything harder than easy dirt roads. the rear suspension feels a bit too firm, but with limited travel it probably has about the right spring rate for my purposes.
ergonomics are good which is a big relief as i didn't want to have to try to move the pegs forward. not sure if other riders would agree, i'm very tall so i don't have to lean forward to reach the bars. raising the seat has helped get rid of the cramped riding position, plus i can always add a pair of those buell footpegs to drop down another inch (part number N0006.1AD at your buell dealer, click here
for a piccie).
next steps will be a basic bashplate, shorter dog bones to kick the rear of the bike up an inch, make some fork protectors out of an old wetsuit to keep dust out of the fork seals, make a small fairing, and some kind of rear rack for luggage. and get rid of that huge exhaust! i hear good things about the danmoto jisu slip on muffler
for the SV650 and at $130 posted i figure it's worth a try if it isn't too loud.
i found these threads very useful for research...
SV650 Adventure (AKA franken bike)
SV650 Wannabe Motard/Adventure Bike
Yet another SV650->Adventure build
SV650 ADV info thread
SV650 shorty pants mod