> It seems to me that the bike is very lean when stock.

In order to meet EPA tailpipe emissions, carburetors have 1) a lean airscrew setting, 2) a fat neck on the slide needle.

Both of these restrict fuel flow from idle to about 2500 rpm.

The low rpm sag can be eliminated by 1) uncapping the airscrew and backing it out about 1/2 turn, and/or 2) removing the plastic needle spacer.

The quickest and easiest fix is the spacer job, it can be done without pulling the carb.  Doing this will override the lean airscrew enough so that the bike will accelerate seamlessly.

Changing the main jet will just richen the mix from mid-range rpm to WO.  Changing the pilot jet will help off-idle sag, but is a more difficult job than necessary.

If you dink with the air filter, leanness will be increased.  The engine aspirates just fine with the stock filter and you will not notice much of a power increase doing this unless you also fit a less restrictive pipe.  If you go with a new pipe and filter you will enter into tuning hell to get the engine dialed in.  If you like to tinker 'a lot', go for it.

Mr 650 wrote on 12/31/69 at 16:00:08:


You are right concerning mixtures etc.  A lean bike getting leaner with a pipe change and then getting back to original mixture with a jet change makes sense.  It would be the same.  They do that with fuel injected engines and their controls now, when someone buys a new pipe.

Secondly it won't have any retro effects, with the exception that all this will probably bring about emmission testing in bikes and anyone with an out of tune bike may have to fix that.

What this really concerns is new motorcycles.  Just consider that ALL Savages or S40s will be configured the same as the CA models are now, in 2006.  The extra plumbing etc....that is about it.

And finally, THIS IS A DONE DEAL.  No need to write to your congressmen or the other doorknobs.  This has been in the works for over 2 years, and I for one have written to my NC congresspeople about this.  Of course, I never got any kinds of answer back

The original EPA Guidelines, as they were called, were more more restrictive than the final version recently passed.  The AMA and the MRF were very involved in the process with a lot of lobbying.  Now, it is done.  Bikes are mandated to be as clean burning as cars by the year 2010, whether we like it or not....and the reason that I bring it up?  Because I think that will make a bikes subject to emissions testing with an inspection in areas like mine where it isn't done now.

ace wrote on 12/31/69 at 16:00:08:


This is hardly a name calling political issue.  WE elected these people.  The EPA has been making these guidelines through several administrations, and it will effect all of us the same as it has for years and years in California.

Quote:


I never saw one on a bike carb. I know Spint cars used to run them on mechanical fuel injected engines.
Those systems work off a crank-driven pump and the jet(s) and barrel valve controls fuel delivery to the motor, completely different from a carb. ???
I would be curious  how/IF something like that would work, where it hooks up,& so forth.

Mr 650 wrote on 12/31/69 at 16:00:08:


The "Dial a Jet" is nothing more than an adjustable venturi tube that is inserted into the intake ahead of the carb...usually by inserting it through the rubber boot.  (It works the same as say the main jet in the carb)

The fuel for the venturi (DAJ) is provided by a tube connected to the float bowl drain, and as air passes the venturi in the intake, fuel is "sucked" from the bowl and into the intake.  The amount of fuel is adjustable.

This richens the entire throttle range.  It is about $60.  Some like it.

klx650sm2002 wrote on 12/31/69 at 16:00:08:


I'm like you, I prefer experimenting with individual jets  

Savage_Greg wrote on 12/31/69 at 16:00:08:


Wow.  Boy I am now in way over my head.   ???  Is the idea behind the "dial-a-jet" that it gives you many different jetting options in one?  That's what it sounds like to me as a novice but I really have no idea.

We need this double barrel deal if I am reading this correctly;
http://www.thunderproducts.com/dial_a_jet_dually.htm
Interesting, I might try one. It looks like it is used mostly by smaller engine aplications. I would like to see some dyno numbers to back it up. All the plastic doesn't inspire confidence, but i like the idea.  I got my headpipe back so I am ready to go set up my carb & exhaust. I will be @ 50th  U.S. Nats all next week, but plan to set-up the carb for the new pipe when I get back in town. I would like another carb to torture test this gizzy with and save my stocker  nd report back.

P.S. If Denco invented it & Vance & Hines sell them it, must do something. I went back and read the info from their site and I would guess the single DaJ might work good on a stock late model LS650 carb. TP says the main needs to be about two jets small. This is about where I should be now, so would be an easy test to just stick one on when i install the new pipe. It didn't say where is the best location to install the jet? Injectors seem to be moving "up the stack" .Toward the air filter on the LS650.(?) The website shows the carb drilled and the new jet extending toward the center of the airway of the carb throat.