There's a wide range of jetting kits and carbie
mods available, but today we are just looking at mostly simple do-it-yourself mods that can be
done very cheaply and give you great performance and economy without an obnxiously loud bike.
And you know how we feel about loud bikes. So we start by ripping off
the side covers, the seat, and the fuel tank. We take off the fuel hose.
These grommets here, you want to take these out before they fall down somewhere. When you pull
the tank off, make sure these rubbers don't fall off.Once the fuel line is off you'll see
this little bit of white plastic, an annoyingly small fuel filter. Replace it with a decent-sized
fuel filter as per this photo. This is a critical mod - this breaether for the vacuum carb.
If it's dirty or blocked, you're going to be wearing your carb, your bike will stop running.
We recommend servicing this every time service your air filter. Adding extra foam is not
just extra protection, then you never have to service inside one. You can just pull this
out easily. I you don't modify your dr650 carb, leave the snorkel in. Loosen off these
bolts, so we can swing the carb around. Loosen that. The choke cable here is very very
fragile. That's plastic in there, it breaks very easily or strips. Now we swing the carb
around, we remove the screws on top. Many replace these screws
because they're garbage. We lift the top off, there's a spring in there.
Don't lose this o-ring, don't let it go missing. There's our needle. This is our
slide. Looking in the top of the carb, this is the slide guide.You
can see those holes each side. When these holes disappear, that's when
it's time to replace your slide guide. It should last 20000km to 30000km. But if
you let this get dirty it'll be way sooner. If you do taper the needle, you can remove the
snorkel, but don't enlarge this air hole you will get increased air intake but just enough to suit
a type of needle that's assuming you don't change your main jet problem with the stock needle it's
too fat down here so the bikes too lean off idle what a lot of guys do is they will drop the needle
here so that they get rid of that bog that happens off idle problem is then it's crap everywhere
else for the rest of the rev range what we're going to do is taper the needle to get good
fuel air mixture right through the red rain so what we're going to do here
is grind this little bit of plastic so it'll change where it sits in the hobby now down in here there's a little shell we have
ground the plastic on this so the needles going to sit lower it'll bypass the shell and be positioned
better so this doesn't need to come completely to a point but fairly close the important thing is
just getting the taper here don't take too much off forget get a shape roughly like this and you
really want to look after this diaphragm is if you do get a little nick in it the bike is not
going to operate properly you slide won't have a vacuum to work against your throttle will pretty
much stop working once the engine is running the vacuum created is what determines how quickly
the slides going to come up we actually drill an extra hole here so that we'll get a better
throttle response so the clicker this slide comes up the quicker the fuel comes in which is
very similar to what a pumper carb does we will also drill out this second hole well then from
the side straight down and in live the second fall as well so we had just one two and a half
mil hole now we have two three millimeter holes because we have shaved that bit of plastic and
it'll sit further down we don't need to make any adjustment of the needle position for Australian
conditions year round this is a good compromise now uzuki with these terrible Philips bolts down
on the float Bowl and are these and stripped very easily they're very easily an important
thing given how tricky these bolts are then not Philips they are actually j.i s and this is a
JIS screwdriver Japanese industrial standard once it comes now we swing the car be around the
other way so we can access this screw again we're using this tool just the risk not bearing
it always check for water and dirt in the bottom of your flat bowl we flip this around more to
access to mange it 1:40 manger if you leave this stock but if you're going to a 150 main jet
here we will cut the airbox main jet coming off mind Jets backing as mentioned earlier make sure this overhang is
still there and get a torch just to make sure the needle is definitely sitting off the shelf
bingo this is 112 mil Juan will be cutting it down to 100 so because we've shortened this spring it
means the throttle response will be faster similar to a pump a card when you throttle off it's also
backs off a bit gentler and smoother as well a smoother ride all over awesome thing to watch out
for when reinstalling this pipe this hose here can drop off and we can see it has this hose can also
kink and you can get the same issue as if it's not on its a hose that you want to check every time
you move this carb at all so we tighten this back up tighten this one back up and then tighten the
car be back up itself probably can't see it with the camera but there is a knots there and a notch
there to allow you to line the car be up correctly and now it's time to drill the air box one thing
to remember these nuts can come out easily if you're not careful we usually just put some sort
of cloth in here prior to cutting this is 2 inches or 51 millimeters and one thing we do is we keep
this as far away from this breather as possible if you go near this breeder you're going to interrupt
the airflow which we think is the main cause of Surgeons there Gordon spent a lot of experimenting
with smaller holes bigger holes different positions this is the one that he's found best and
this size hole works well regardless of how much further you go with the main jet sights very
handy thing in dusty conditions is put one of these chucks super wipes in here without filter
oil or liquid tuck this around properly and the beauty is that when you travel off the dust will
actually fall off and into the bottom of the box like stay in the bottom Canadians love this sort
of stuff because they're so lazy now the thing is this weld in here sometimes is really messy
and it always restricts the diameter going into the pipe and it creates turbulence you'll get a
significant power difference simply by grinding this nice and flat now the trick though is not
to take the whole thing out this is what holds these two bits together so you probably want to
leave about 1 mil of weld still there minimum you can take it more than this but this is
what's recommended to leave just to keep the strength there if you really wanted it full
performance of course you can grind it smooth on the inside that a dwelled around here even if
you haven't modded you buy it should be upon and a half screws out once you do these mods it will
normally be one and three-quarters turns out this can be plus or minus half a turn depending
on temperature and other factors we highly recommend the Suzuki GSX our exhaust for good
power gains a great sound but far quieter than aftermarket exhausts according to dyno charts
we've seen these mods all provide about a 10% improvement across the rev range and make a big
difference to fuel economy better starting and how smoothly it runs at low revs just do this
up snugly not quite it's a great idea to lock tight anything on a dr when you're screwing it
back up use the caps bolts that come with the GSXR now the map was on properly we tighten all
these remaining bolts correctly and including the header pipe hole these bolts in particular
you want lock tight on these vibrate easily now we put this on prime after the car Bea's
been drained just so it replenishes easily an important thing to remember is these little
holes here they go on little tabs to make sure the side cutters stay in securely so
because the engines running so much better now we've got to reduce the idle speed but
set up and now we do a test ride what we're looking for is a little bit of fluffiness a
little bit of hesitation just around quarter throttle if so we may need reaching it
a bit and change the needle position you
