DRZ-400S Minor performance tweaks - and mis-fueling.

Hello everybody, new to Thumpertalk here. 


Anyways, got myself a DRZ400S, for street riding (strictly). 

Have a set of Avon Roadriders on it, (noice tyres mate)


I was sloppy/noob-like with maintenance/tweaks once I got the bike, it had sat for years, but was in good condition. 


So far, the thing's I've done, (it's at 7300 miles now)


Upon receiving bike, 

New tires (Avons)

New rear sprocket

New chain, (also had service at this stage). 


Then the counter-shaft(?) seal went, and it pissed oil all over the rear tire for a few days. I topped it up regularly, and then went and had it replaced. No oil leaks anymore! Great. 


Next, I filled it to the brim with supreme diesel. I know, (div), standard excuse - was in a rush, and the supreme label was blue and green - same as the super unleaded. Dammit. 


Got 30mtrs, and smoke. Lots. 


Pushed back to fuel station, drained tank from carb pipe, filled with supreme unleaded, (duh), and then ran it through. Ran rough for a week with some smoke, and then some more Redex (fuel system cleaner). 


And then fine, yahooo! 


Since then, I've re-tensioned the chain, as you do, and tightened the clutch lever cable slightly, as I was starting to get clutch slip under load. 

That's fine now (glad), as I didn't want to have to buy a new clutch kit. (skint). 


what can I do now, to keep the performance of my beloved DRZ at a good standard, if not improve it slightly? 


I can't do 3x3, can't afford re-jet kit at this time, plus I want to keep bike in (mostly) stock condition. 


Any advice regarding minor performance parts, at the most air filter - type stuff? Or minor performance tweaks that will make this bike a sharper, more aggresive beast - that I know it can be. The adjustment of the clutch lever cable made it feel sharper. 


Thanks Erry'body

Don't bother with performance modifications until you've saved up for a new carb or a jet kit. That carb with that jetting and the tiny airbox hole is the single worst performance bottleneck on the stock bike. Next is the suspension, after that the cams and exhaust. IMO.


An example: A freer-flowing air filter could increase airflow (although afaik they don't do much - the stock filter is not bad!) - but you'd need a way to add fuel as well - and the bike is already jetted hella lean to pass emissions tests, so you wouldn't gain anything.


There's a way to do the 3x3 mod without an entire carb kit: "The DRZ400S comes stock with a 142.5 main jet, 22.5 pilot fuel jet, change that to a 150 main jet, 27.5 pilot. The jets can be purchased from many motorcycle shops. This option will cost under $15. This jetting option is better than stock, but not even close to as good as jetting option one listed above. I highly recommend jetting option one." - source: http://www.4strokes.com/tech/suzuki/drz400su.asp ... note that that site is quite old and not considered really up to date on what's what, afaik. The 3x3 mod magic is mostly in the needle taper, which is afaik only available from a jet kit.


I got my JD jet kit for less than MSRP after some mild hunting on EBay.

Edited by Anthon Berg

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