Jetting: Part 1

[jonathan180iq]

Originally Posted by Easy Rider

until I hit that wall at the top end. That's all I really want to do is get just a tad bit more on the highway in top gear.

So we're on the same page. The only draw back of the 16T sprocket is this dead end around 65-70mph. Once you get up there, the larger sprocket makes the bike feel like it's too heavy to go much faster.

This is the only reason that I am altering the filter to begin with. I rode my buddy Mau's bike, which still has a 15T sprocket, and it feels more peppy and free spinning. He can also pull away from me on the open road.

Hopefully, with the correct carb adjustments and the pod filter, this dead spot will be corrected. If all goes according to plan, the added boost will be beneficial to everyone, sprocket change or not, but will allow those of us with the larger gearing to run at higher freeway speeds.

[jonathan180iq]

Originally Posted by Jaime

The air box isn't restrictive, but we must remove it if we want to use an universal filter..

Right.

The air box isn't restrictive. Actually, it is only there to create a resonance effect and help in producing torque on the low end and give an area to catch blow-by oil from the crankcase and recycle some nasty engine fumes.

The restrictive part of the system is the filter and the filter mouth. (the area where air enters the filter)
As Easyrider has said, it might be possible to simply gut some of the filter and open up some air flow.

Since removing the D@#% air box is so frustrating, this may not be a bad idea. However, if you want to get the most out of the alterations, I'd suggest just pulling the whole system for a pod filter, as the paper filter element is the flow restrictor.

Expect results this weekend.

[jonathan180iq]

I didn't get as much accomplished this weekend as I had planned.

I did manage to get the oil changed and a fuel filter installed.

For what it's worth, the switch to synthetic makes the bike seem to rev easier. This may be my imagination, but it feels really free, responsive and willing to rev up.

I'm at a crossroads now, with this Franklin, Ga. trip coming up this weekend. I don't want to rush my results with the jetting, but I would like to test it over a long trip. However, I don't want to encounter a problem 200 miles from home. The boys in Franklin will be the first to know if I got it done.

[jonathan180iq]

Here it is. The final word on this.

I spent 2.5 hours working on this thing this afternoon and it's not worth it.

The jetting wasn't as hard as I made it out to be. The midrange was spot on and the main jet only required an increase to 125. The idle mixture only needed to be slightly tuned.

Even then, aside from some AWESOMELY raunchy noise under full throttle, the bike makes no more power. I did notice a loss of power taking off from a stop, but it was negligable. As Badbob mentioned in another post, it was, unfortunately a waste of time.

I'll post some photos from the process tomorrow morning.

I'm a bit discouraged, but I've got the bike back together and she's ready for the ride down to Franklin tomorrow.

SEe you then,
Jonathan

[Jaime]

Originally Posted by jonathan180iq

Here it is. The final word on this.

I spent 2.5 hours working on this thing this afternoon and it's not worth it.

The jetting wasn't as hard as I made it out to be. The midrange was spot on and the main jet only required an increase to 125. The idle mixture only needed to be slightly tuned.

Even then, aside from some AWESOMELY raunchy noise under full throttle, the bike makes no more power. I did notice a loss of power taking off from a stop, but it was negligable. As Badbob mentioned in another post, it was, unfortunately a waste of time.

I'll post some photos from the process tomorrow morning.

I'm a bit discouraged, but I've got the bike back together and she's ready for the ride down to Franklin tomorrow.

SEe you then,
Jonathan

Which filter are you using right now? I bought a small one and the jetting is similar to yours, but without filter even a 130 is still lean at full throttle.
Now I'm waiting for a big K&N filter and I spect a higher jetting than 125... Keep in mind that a "richer" jet needle could increase power too (the stock needle limits the maximum fuel flow of bigger main jets, even shiming it) and a bigger pilot jet will remove the power loss at taking off, as I've checked.

Also, now it's possible that the exhaust system would be the limiting factor.

[jonathan180iq]

I stopped taking pictures the second time that I pulled the carbs. The sun was starting to go down and I wanted to get the work done before it got too late and I couldn't see the important bits.

[Jaime]

Wow, just the same filter I use... Definitely, it's not enough to improve performance. Too small.
Anyway, it's not all lost. I tryed my car's big Green filter and it has more potential than the tiny filter. There are still chances.






I started removing the fuel tank too, but it's not necessary for any task about the carburetor.

[jonathan180iq]

WOAH! What is that electronic device on the side of your carb? We don't have those....

[Jaime]

Originally Posted by jonathan180iq

WOAH! What is that electronic device on the side of your carb? We don't have those....

It's a Throttle Position Sensor (TPS) that sends a signal to the electronic ignition. It's installed in latest years models, but I don't know what it does. It probably reduces contamination.

In injection vehicles, the TPS determines the amount of fuel needed, but in this case it isn't possible.

[jonathan180iq]

Wierd. I have a 2006. That's pretty new.

Thanks for the info.