Setting up the bike for touring

I know it's been a while since I posted to this blog, but I'm currently working on setting up the KLR for touring.  I've been slowly making mods over the last few months to make it more highway-worthy.

Among them:

Grip Puppies

Laminar Lip

Pannier Racks

Cruise Control

And tons of other mods.  I promise I'll get back here and add some content soon.

Carburetor Tuning Procedure (Mine)

Carburetor tuning is an art, and I have spent many hours of frustration trying to come up with a procedure that works well. After all the headaches, I have developed this procedure and have used it on three bikes:

My '09 KLR
My '92 Seca II
My friends V-star 1100

This may not be the "by the book way" of doing it, but I get really good results from this.

The instructions that come with a DynoJet kit will get you CLOSE. You will still have to do some tuning to get it right. If you have driveability problems, give this a try. I'm not a mechanic, but I'm an enthusiast who's played a lot with carb tuning.

Primer:
Pilot and (and starter, if equipped) jets affect ONLY the idle and transition from idle to needle. The mixture screw affects ONLY this circuit.

1. Adjust the size of the main first. The main jet in most CV slide carburetors feeds the needle as well, so changing the main will most likely require adjusting the needle. You can do this by sound/feel if you have a good ear for it, or try the spark plug color trick. Set the needle mid-range to adjust the size of the main.

To do this: find a nice, deserted stretch of road at your operating altitude of choice. Warm up the bike to operating temperature. Don't worry about hesitations or bad behaviour at anything other than full throttle right now. Take the bike out on the road and run it out to full throttle, let it run for 15-20 seconds, then simultaneously pull in the clutch and hit the kill switch. Coast to the side of the road. Pull a spark plug and examine its color. You're looking for a nice gray. White = too lean, darker = too rich. Another indicator is rough running at full throttle, indicating a rich condition. Change the mains until you get the desired full-throttle performance.

Next, adjust the needle up until you get mid-range hesitations when the bike is hot, after leaving it idle for a bit until the fan kicks in, then drop it a notch. This gives you the richest setting without incomplete atomization.

Put it all back together and warm the bike up again. Adjust the idle to its highest point that does not drift down when you blip the throttle. When you blip the throttle, it should return to idle quickly, not slowly glide down. Once you've done this, adjust the idle mixture screw until you have it set where you have the highest idle. Then back off the idle thumbscrew to desired hot idle rpm (blip the throttle a few times to ensure it stays where you want it). Bear in mind that when the bike is cold it will idle at a lower rpm than when it's hot. This may take some massaging.

Your bike should now cold start easier, pop less on deceleration and have more go-fast.

Synchronization of multi-carb engines is out of scope of this posting.

Carburetor Jetting and Tuning Tips

Just as a primer to those messing with jetting, here are the results of my learnin' based on spending a lot of time tuning my old Seca II. I learned this the hard way, and it's even harder because you have to do everything x4. These are some general tuning tips I've learned by trial-and-error.

* Any time you do anything to increase flow of air or exhaust, you need to richen everything. The opposite is true of restriction.
-From idle to 1/8 throttle or so: Pilot (Idle mixture) screw
-from 1/8 to about 2/3 throttle: needle
-2/3 and up: mains
These areas overlap, but this is a good rule-of-thumb

*watch out for altitude. If you tune at sea level, then go up a few thousand feet, behaviour could be different.

*If you get popping on deceleration (with throttle closed) most likely you are too lean, but you could also have an exhaust leak or air injection problem if your bike is so equipped. This could also be an indication that your pilot jets are becoming clogged if you have made no adjustments, especially if the bike has sat for a while.

*If the bike runs well cold, then develops a hesitation when it warms up, you're too rich.

*If it runs well warm, but is cold-blooded and you have to choke the crap out of it, you're too lean.

*If you install a needle with an aggressive taper, like the KLX needle, and you have stock exhaust, you may have to go DOWN a jet size or two.

*if it hesitates coming off idle when warm, lean up the pilot circuit a hair.

*If it does the same at 1/4 throttle or so, lower the needle a notch.

*If you rejet and actually lose top end, but gain accelleration, the main is probably too rich. (you'll hear a distinct change in tone if you're too rich. )

All of these changes affect the others, so unless you're an expert, you'll have to keep tweaking until you hit that magical driveability balance... where it's smooth throughout the whole range.

Remember. In carburetors, RPM is not important... it is about throttle position.