DRZ 400E Performance Mods.

[BARBUSTER426]

I have a 02 drz400. I have not even rode it yet. I cut the exhaust tip to 1 3/8in. Now I was wondering about jetting changes. Or other low cost performance mods. The bike is just off the showroom floor so it is all stock. Any advice would be a great help. I heard to put a 165 main jet that seems to be a bit much when I removed the stock jet it is only a 142.

 

[Wolf]

The 165 is fine, I switched between the 162 and the 165 a few times, liked the 165 better. What you really have to do is to remove the coast enrichener thingy on the side of the carb and jet accordingly. Go to Thumpertalk.com There is lots of info there on how to do it. I did it a month or so ago and the only regret I have is that I didn't do it sooner. It changes your bike completely! Total Cost: $25 plus time.
Good Luck!

 

[flynbryan]

There was a post on this same information in this forum no earlier than last week. Do a search on "DRZ400" and see what you come up with. They had alot of really good info.

 

[JBTX]

Originally posted by flynbryan
There was a post on this same information in this forum no earlier than last week. Do a search on "DRZ400" and see what you come up with. They had alot of really good info.

The post last week was regarding the S model, the E model uses a different carb, cams, and has less compression.

 

[BARBUSTER426]

More info on the removal of the coast enrichener would be a big help. Where to get necessary parts to remove and what is involved. How much improvement and where is the improvement noticed in the power range.

 

[Wolf]

You will need vacuum plugs (3 of them) get a variety pack from your Auto parts store. You will need the jets (38/70/ 162) and a EMM Needle.
Total cost about 25 bucks. You can find detailed instructions, specs, and photos on Thumpertalk.com
mnelson has a very goo web site about all this.

 

[cetris]

I don't understand why people bother to remove the coast enrichening circuit. Other than saving a couple of ounces and getting rid of a couple of short hoses, what is the benefit?

Since you bike is brand new, I would suggest riding it stock until it is broken in before you start tinkering with it too much. You'll better appreciate the jetting mods if you spend some time riding it with stock jettting. The general consensus on the mod to the stock pipe seems to be that it doesn't get you much other than noise. When you do get around to jetting it, pull the plug out of the intake snorkel, replace the stock 142 main with a 160 or 165 main (unless you spend a lot of time at high elevations) and replace the 45 pilot jet with a 48- set the airscrew accordingly. The stock needle is fine- from what I have read regarding others experiences, it is questionable whether or not changing the needle will provide any significant improvements. Two jets and removing the intake snorkel will get you a lot of improvement for very little money. Have fun.

Originally posted by Wolf
You will need vacuum plugs (3 of them) get a variety pack from your Auto parts store. You will need the jets (38/70/ 162) and a EMM Needle.
Total cost about 25 bucks. You can find detailed instructions, specs, and photos on Thumpertalk.com
mnelson has a very goo web site about all this.

 

[Wolf]

Well, the coast enrichener removal will make your bike "really" nice! I can't explain why, but it does. I've done all the other mods...airbox, exhaust, jetting etc.It all helped, but when I changed the setup on the carb and took off the enrichener (all it is is a quick fix to reduce backfiring!) and jetted accordingly, it made a world of difference.
I guess if you don't try it you won't find out, and that's ok, but give me a reason why you wouldn't want to try it? Especially when there are tons of guys (gals) that tried it and were successful?
By the way, unless you remove the enrichener the stock needle is fine.
To answer your question cetris: The benefit is even better throttle response, absolutely no hick up when you wack the throttle, and better power delivery! By the way, I still run the stock (modified) pipe.
I hate to plug another site, but all the info is on there!

 

[beefking]

The point of removing the coast enricher is that without it, the carb is much easier to jet and once jetted correctly, there is no bog from hitting the throttle open. The only purpose of the "coast enricher" is to add fuel on deceleration to prevent popping, but it really isn't very good at effectively doing this, and the plunger that is in the unit wears out after a while and becomes useless.

If you haven't even ridden the bike yet, I suggest you put a 160 main in there and just start breaking it in. After a bit of riding is on it, under the seat on the airbox is a rubber "plug"; take it out and feed it to the dog. Then slap in a 48 pilot jet and depending on what your elevation is jump to a 165 or so main jet. www.drz.info has the advanced jetting specs needed, they are spot on too and give very crisp throttle response.

Another overlooked thing is the suspension. What kind of riding will you be doing, and how much do you weigh? As you probably know the stock DRZ suspension is pretty soft, especially if you wiegh over 185 lbs. A respring and maybe revalve will let you go ALOT faster than just going for the power mods...but go for the free power mods after she's all broken in.

Good luck.
PS I've got over 3,200 off road miles on my 01 400E and no problems yet, just getting ready to change out the valve shim, but thats it. Nothin major. ;)