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DRz400sm Build Up Q's

7464 Views 15 Replies 12 Participants Last post by  indyZrider
So I just got my 2008 Drz400sm, finaly :thumbup:. Took her up in the twisties on Hwy. 9 (Inbetween Saratoga and Santa Cruz, Ca.) for those of you who don't know. And already I have noticed a couple things. Sorry for the there being so much reading involved

-Steering has a little wobble at 60 -70 mph.
-Handles exceptionaly well (In Twisties, and pretty good on Freeway)
-Needs a better fitting seat
-Needs more power
-Need more distance out of the tank
-Brakes work close to exptionaly well.

The Steering issue I know exactly how to fix that.

The seat item I still need to do some more investigating on, but being that this bike is really only made for the short rides and around town, this item will be put on hold.

For the more power I have been reading up on upgrading the exhaust to , know I already know that if I dump it there goes the atleast oneside so spare me on that lecture. Also with the exhaust comes a jet kit , as well as the 3X3 airbox mod.

As for the distance per tank (DPT), theres a new abreviation you can add to your list, I have done absolutey no research on this item. I may just leave the tank at stock. I have a 3.6 gallon tank on my 2000 Yz250 and yea of course it goes alot further, but at the same time it does get bulky and heavy.

My question is that does the exhaust, jet kit and 3X3 mod be enough to get more power out of her without boring it out ( Thats latter on when the motor goes). Also knowing that I'll be boring it out later on to 434cc would the list above still be able to be applied. My thoughts is that I would only need to change the jets some.

What else would you add to it? Or am I going down the right path? Also my ultimate plan for this bike is to have almost a show bike when completed.
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show bike my bike shows alot of scratches and wear,:hmmm: heres a thread for seat options. im personally not going to do the BB on my bike because ive heard alot of good and alot of bad. im gonna put some E cams and an fcr and im sure ill be good with that. the 3x3 does help alot though if done with jet kit and pipe.
Get a full exhaust system not a slip on. The header chokes the motor. Get a MRD ssw system or a Yosh rs2 rs3. James Dean make the optimal jet kit for DRZ,its a more complete kit and thier needle design is excellent. Plus it comes with Allen head bolts to replace the pesky Phillips head bolts on bowl. You will need a nut driver to remove screws! You can change your gearing and It can either help or hurt fuel mileage. Alot of riders choose a lower gearing to help acceleration. Like 14/42 or 15/44 stock is 15/41 but this hinders mileage. Others go to a 15/39 or even 16/41. This increases roll on top end speed. As far as Larger tanks go,IMHO think they look like ass. Just fill up every 100 miles. Pipe and exhaust really open up the DRZ. Just don't expect MX bike power. Later you can add fcr39 carb, E model or Hot Cam camshafts, and even a big bore kit. For the headshake,check bearings in steering head,Factory was known for not putting much grease on bearings. Could be tires out of balance. My suggestion: get your suspension done first by a reputable suspension specialist. The bikes have good shock and forks they just need a little upgrade. Try Dave at he has the DRZ suspension wired.

Hope this helps and Welcome to smj
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Oh,if you go to a big bore,you will need to upgrade to a FCR carb, the stock carb wont handle increased size. Depending how large you go will determine carb size. Big bore=FCR 39. Big Bore plus stroker=fcr41.
FCR is a good upgrade. It offers much quicker throttle response.

Add stainless steel brake line to front....will help tighten up lever. Stock lines are mushy and wear out.
I have dyno-ed stock DRZ's up to turbo drz's, and I can tell you that the stock drzsm in stock trim makes about 30hp at the wheel. Uncorked (full exhaust, 3x3 and a good air filter with proper jetting) a drz will make about 35hp. Cams and an FCR can add up to 5 more hp, and Ive seen 65hp out of a turbo drz. "Enough" is a term every rider understands differently. Some are fine with uncorking it, others arent satisfied until every last drop of potential horsepower has been found. The choice is yours, good luck!
I'm in SF, and I ride Gazzos/Empire/Stage/Pescadero/Alpine/china grade all the time. Mines/mt hammy is also sweet, as is fairfax/bolinas north of the bridge.

Hit me up, I ride those SC twisties almost every weekend!
muxherdlr is dead on with his recommendations, and suspension is a must if you're going to push the bike. No need for a damper after having it done by Dave. My bike dyno'd 41.8 rwhp with the mods in my sig. For comparisons sake, a stock DRZ puts down 32-33 on the same dyno.
Just did an MRD/SSW, FCR39, stage 1 Hotcams, SS lines, and a few other small things. LOVE the bike now! Such a HUGE improvement! It used to run out of power well before it ran out of revs, now it pulls hard right to the limiter. I definitely suggest these mods to anyone with a DRZ!:thumbup:

I might also do a BB kit this winter, but I'm gonna have plenty of fun with my current mods first!
Well it looks like I'm settling on the Yoshi RS4 exhaust. The only thing that I may want to change is try and relocate the battery in the center of the bike. Right now the weight is evened out fairly good and I'd like to keep it that way. And obviously with the exhaust comes the 3X3 mod which I am so glad that it cost so much NOOOOTTTTT.

Not exatcly sure on what jet kit I would want. I would like to get one that comes with all the sizes for all the jets, but also to get one that performs well with the RS4.

All the other item will be on hold. Need some mo dinero for the 4X4 crawler.

James Dean has everything you need. You may want to get an extended fuel screw as well $14. Helps dial in carb.
+1 for the JD jet kit. That with a full pipe and 3x3 is really the best first mod to get rid of the stock DRZ power blues.
I did the 3x3 and JD jet kit and extended fuel screw to my stock DRZ, definitely feel a difference, way smoother pull and eliminates the dead spots or skips or what ever you wanna call it when ur cruising at slower speeds...
I ordered a Yosh RS2 full exhaust that should be here in a few probably gonna end up getting a FCR carb and callin it good!!
LoL at first I was against spending the $$ on the exhaust and carb but if you want more power, ive come to realize :hmmm: they both are necessary
carb question

the fcr39 carb is found where? only think i'm missing is the carb and a full exhaust. the 3x3 was done before i bought it. kind of a little bigger than 3x3 though. was thinking about getting a new air box and recutting the 3x3 out of it. where could i get a new air box. i have a 05 drz400sm. thanks
the fcr39 carb is found where? only think i'm missing is the carb and a full exhaust. the 3x3 was done before i bought it. kind of a little bigger than 3x3 though. was thinking about getting a new air box and recutting the 3x3 out of it. where could i get a new air box. i have a 05 drz400sm. thanks
The Thumpertalk store sells the complete kit with everything you will need.
need help jetting

:headscrat:headscrati have a yoshi rs3 slipon a bmc air filter and gonna do the 3x3 mod.Also have a stage 1 and 2 dynojet kit. my question is what jet to use? 155 or 160 and other imfo would be greatly appreciated. i live in ny so idk if elevation has anything to do with thanks so much in advance. plan on doing carb and cams next season!
slap a new cam chain in there and a mcct so youll have tons of life on the new less thing to worry about.....
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