Suzuki DR650 Carburetor Page

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Suzuki DR650 Carburetor Page

Suzuki DR650

The stock Mikuni BST40SS carburetor in DR650s leave much to be desired. This is especially true with the pre1996 DR650s that like to stall at low RPMs.

Stock Pre 96 Carb

As the DR650's carburetor is barely adequate and a carburetor upgrade can make a huge difference in perceived performance, responsiveness, fuel effeciency and reliability.

At least for the newer DR650 the jet configuration on the Mikuni BST 40SS carb is as follows:

main 140, pilot 42.5, needle 6F19 clip on 3rd slot (Australian, Canadian and UK needle)
US models use a 6F23 fixed clip position jet needle and a Y-5M needle jet

Mikuni TM40

Mikuni TM40

Mikuni TM40

The Mikuni TM40 Pumper Carburetor used for Harley Davidson bikes is more or less a bolt on upgrade. You can tweak the stock throttle cables to work and the carburetor mates up with both pre and post 1996 DR650s - although it is pretty tight on the pre 1996 DR650s. This drastically improves responsiveness and makes kick starts much much easier. It will take a sluggish bike and allow it to lift the front wheel without feathering the clutch.

Links:

HS40 (TM40)Tuning Manual, Exploded View and Parts List
Hessler's Mikuni flat slide carburetor with accelerator pump - Germany
Procycle's Mikuni TM40 Pumper Carburetor kit
Thumpertalk - Mikuni TM40 Pumper Carburetor kit from procycle.com - anygood?

Keihin FCR-MX

Keihin FCR-MX Carburetor

The Keihin FCR-MX has also been used on newer DR650s with what sounds like pretty impressive results.

Related Links:

Keihin
Thumpertalk - Keihin 39mm FCR-MX Install
mxrob.com mxrob_007 - DR650 mod
- Keihin FCR-MX Old page
- web.archive FCR_Install
ADV Rider pre'96 thead - FCR on 95 DR650SE - note intrusive starter

Edelbrock Carburetor

Edelbrock Carburetor

These have been used in DR650s and other Dual Sports.

Related Links:

Edelbrock

Choke

The choke cable is prone to moisture accumulation which can cause cable corrosion and accumulation of water in the choke. This can lead to unexpected engine cutoff when the handlebars are turned.

Choke Knob

Choke Knob

To avoid choke cable problems, the entire cable can be removed and a aftermarket Hand Choke can be installed directly in the carburetor. You will need to notch the throttle wheel stop with a file to allow for full throttle without hitting the new Hand Choke Conversion.

After installation of the choke knob, choke adjustments will need to be made directly on the carburetor when starting and warming up your bike. This isn't too difficult to do while sitting on the bike.

Reference:

Rejetting

If you modify your air intake box (see the Air Filter page), the you will need to adjust the carburetor and most likely need to rejet the carb to avoid running too lean. Figuring out the best setup can be quite the challenge, but luckily there are a few kits and pointers available to those that wish to tweak.

List of tweaks:

Removing the snorkel (More air).
Raising the stock needle 1-2mm (Best for stock in combination with snorkel removal).
Opening the top of the airbox (Even more air but needs a complete re-jet).
Drilling 2nd hole in carb slide (Improve slide response speed).
Shortening the diaphragm spring (Decrease the preload - increase slide speed some more).
145 pilot jet (Up 1 size - reduce popping).
1.2 pilot air jet (Up 2 sizes - reduce off-idle rich bog).
New Y-5M needle jet (If the brass OEM one wears you get a big off idle bog and it will seem to run rich).

Related Links:

Dynojet Research's kit 1990-2009 DR650 Satge1&2 kit Part# 3138
Factory Pro - 1996-2006 kits plus carb parts (jets)
Sudco part catalog

Fuel Injection

This is not a mod I am familiar with. You may find some information and a start at MicroSquirt.com

Please feel free to link to this site so that others can find it. It's easy to link to this site, just copy one of the texts below onto your web page:

<a href="http://DR650.zenseeker.net">Zen's DR650</a>

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