01 DRZ400S Cheap Upgrades

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01 DRZ400S Cheap Upgrades

Post by 4Strokes » Sun Jun 05, 2016 11:49 am

Topic: DRZ400S cheap upgrades
Author: matt_ct
Posted: 07/12/2005 12:22:55 PM

I just bought an '01 DR-Z400S, the two previous owners have left it stock. I need some more power. I'm pretty new to all of this so I'm not sure what my best options are. I am a die hard K&N fan so of course I have already installed the air filter. I will be riding the bike between 4,000-9,000 feet and half road, half trail riding. What do I need to do to open the air box? Is there a downside to that? I don't want to spend much money does that mean a pipe is not my next step? Most importantly! The bike started to cut out when I really get on it? is this most likely jetting? should I be working on getting the bike some more air before getting smaller jets? Any help would be great, limited experience make it semi-simple. THANKS

Reply by tomass on 07/12/2005 4:41:18 PM
Hey. Definitely don't get a smaller jet. Your bike is already lean from the factory. I don't know what the cause of your bike cutting out is, but I can answer your other questions.

First of all, there are no cheap upgrades that I know of. You would want to get an aftermarket exhaust, or open up your stock exhaust. Until you do that, a KnN air filter and opening up your air box will make little difference. If you do that, you will need to get a Dynojet jet kit.

Reply by smcelhe on 07/13/2005 09:31:10 AM
My friend and I have 03 DRZ400S. both our bikes had a minor hesitation when we got on the throttle. you really noticed it when you were on the road running about 50mph and nailed the throttle. Especially on a hill. We cut a hole in the top of the air box and the hesitation is gone.

Reply by midlothianjoe on 08/01/2005 08:31:59 AM
I had the same problem with my 04 DRZ400S. I switched to a TwinAir filter and cut two 1 inch holes in the top of the air box. I did not rejet the carb and the bike runs great. I took a ride last night riding on the street between 55 and 60, I can nail the throttle and the bike just takes off, before it would hesitate then take off. This absolutely works.

Reply by xti on 10/16/2005 7:18:11 PM
Won't this make your bike run leaner?

Reply by tomass on 10/18/2005 1:08:28 PM
Yes. That's why I don't know the reason their bikes ran better after making them more lean. Especially since I've heard time and time again that those bikes come lean from the factory. Going more lean sounds like it could do damage. But I'm no mechanic.

Reply by DRZRider84 on 10/20/2005 9:42:20 PM
If you are going to cut holes in your airbox and get a filter, DEFINITELY change out your jetting... If you do not, your bike will FEEL like it runs a lot better, but it will also hurt the motor and greatly reduce the life of the motor. Its like running your motor constantly a qt. low on motor oil. Not good. My recommendation is to get a UNI, K&N, or twin air filter, cut a hole in the airbox, and get the DynoJet Stage 1 kit, like tomass recommends. It wont make a huge difference, but it will get rid of the hesitation for the most part. As for the bike cutting out Matt, did the previous owner(s) let the bike sit for a long time? It sounds like some kind of carburetion problem for sure, and could quite possibly get fixed if you get the jetting kit i mentioned above. Another minor tweak you could do is cutting the little tip out of the end cap on your exhaust. Again, not a big difference, but it makes a little more power and noise, and will hold you over till you get the pennies saved up for a full exhaust, namely the Yoshimura Ti system. That's exactly what i did. Just don't cut out the spark arrestor :) Also, if you haven't done this yet, read the DRZ article by Matt Nelson found on this site. A lot of good things in there, and will get you a little more familiar with this bike. I have an 03 DRZ400S, my first Suzuki, and that article was a good kickstart to what to do with this bike.

Article: DRZ400S Upgrades by Matt Nelson
Article: DRZ400E Carb Jetting by Matt Nelson

Reply by tomass on 10/22/2005 12:26:28 PM
I have an 02 DRZ 400-S and that article by Matt Nelson is what I used to do the upgrades on my bike. A full exhaust system, Dynojet needle and big spring and keep stock jet, KnN filter, and opened up the airbox. It really runs great. Even when my bike was stock, it never had any hesitation like mentioned above.

Reply by Len Clements on 06/22/2006 11:32:49 AM
I know this is an old thread but the DR-Z400S is still new to me. I just want to comment on the hesitation problem touched on in this thread.

Last weekend I had my new DRZ on the trails up at 8000 feet in elevation. The engine ran reasonably well; down on power as you would expect due to the high elevation and hot air (summer in Arizona).

The only real problem was a very noticeable hesitation at about half throttle. The engine seems to cut out and then catch as you crank on more than half throttle.

I'm pretty sure that it must be running sloppy rich and this is causing the hesitation. Since most of my riding is done at lower elevations I think I'll leave the stock jetting alone for now.

I guess I should be glad that it runs at all up in the thin air.

I love this bike!

Reply by crf230rider on 06/29/2006 08:24:14 AM
well many people do not know the difference between rich and lean. rich is when you are getting more fuel into the carb and lean is when you are getting less.the more you have its like flooding your engine. your engine will bog down and a start then move but will go slower. lean when you don't have enough the engine might cut out, ruin your engine, you will go faster but its not good for your engine.

Reply by courier11sec on 06/28/2008 8:21:05 PM
Wish I had joined this forum before doing my jet kit on my '06 drz400s. I thought it was pretty weird they provided an even smaller jet than factory. Guess I'll redo it.

Reply by tomass on 06/29/2008 3:46:53 PM
You'll notice the difference.

Reply by courier11sec on 07/04/2008 4:04:32 PM
put the stock main jet back in and went to a 27.5 pilot on the advice of a bike mechanic friend of mine. it's better, but I still feel like it needs more power. I ordered a power cap on eBay to replace the stock muffler end cap. we'll see how that does. I'd like the bike to pull the front wheel in second with nothing more than throttle input. If it doesn't do it after this I guess I'll look into re-gearing. Suggestions on that?

Reply by courier11sec on 07/08/2008 11:04:39 PM
power cap seems to help. Sure sounds cool if nothing else. may jet up a bit further.

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