Stable idle?

[Neil E.]

If you could find a proper M5 screw/bolt with a shank, an o-ring could also be used.

Why didn't I think of that? There might be a size that sits in the counterbore under the spring and puts enough tension on the screw to hold it secure. The screw wouldn't need a plain shank, since we're not looking for true seal, just a way to secure the screw better.

Teflon tape would also be a valid repair as long as you keep it a ways back from the tip. The slide stop screw does not intersect with any fuel passageways.

 

[Neil E.]

The goal of having the slide at it's lowest possible setting is correct. I noticed an improvement right away. It runs cleaner just off idle. In view of this, I changed to the 38 pilot (from the 40). No noticeable change.

Does anyone have any idea why these carbs show so little response to air screw adjustment?

I get no difference from anything over 2 turns out. I can say that small pilot jets make the choke more effective. While some folks don't like the cable choke, I find it is handy for teasing the choke setting while warming up (as opposed to the plunger style being full on).

 

[Jakobi]

When you get in the right range the AS will start to make more of a change, although I agree with you that on the stand at idle its not a very noticable thing. I barely notice much change in idle revs until I richen it until it stalls, or lean it out until the idle hangs. What I do notice is the change in the delivery off idle when actually riding the bike. Changes as small as 1/8th of a turn are noticable so the AS is definately doing its job.

 

[Neil E.]

The biggest nuisance for me is when I'm off the trail bushwhacking. I admit that this is not what the bike is designed for, but idling IN GEAR while fighting overgrowth is difficult (clutch is pulled in).

The bike is heating up and the slight clutch drag slows the engine into flame-out territory. A high enough idle to avoid this results in a fairly high idle at all other times. I have no clutch squawking with synthetic Rotella 5w-40.

The 2011 has a 160 degree thermostat in the right side rad hose. I have the Trailtech Voyager temperature sensor in the left hose. The Voyager does a good job of temperature logging. Cruising along a fireroad shows about 120*F, flowing single track about 130*F and tighter single track about 140*F.

Bushwacking is at 160*F and if I'm stuck in trail trash it goes to 180*F. The thermostat must have a large bleed hole because the right rad feels about the same temperature as the left rad. These temperature swings are great enough that they must have some effect on jetting.

 

[3beejay3]

Neil-

I'm no expert, but perhaps you may want to look at focusing all your jetting and carb mods on the engine speed range of idle to about 5000rpm.

Firstly, it should help to stabilize your lower speed airflow a bit more via a plate in the intake horn(as we've talked about), or maybe even with a smaller diameter carb(call me crazy) .

Any 2t I've ever ridden usually doesn't carburate well at lower speeds for longer periods. After about 1/4-1/3 throttle, they generally get better & better all they way to WFO, as the airflow gets more and more stable at increasingly faster RPMs.

Because you spend most of your riding at lower engine speeds, it may be beneficial to essentially fool the carb into thinking the engine is at a higher RPM than it is, by using a carb plate, or a smaller dia carb.......
A smaller dia carb should speed up air velocity thru it at lower speeds and help stabilize the airflow earlier, which should help improve fuel metering etc. Its should also help stabilize the idle better........

It will hurt top end, but you're hardly ever there, so that shouldn't matter too much...

Either that, or the fuel injection system now being offered by- http://www.highgaintuning.com/
should solve your issues(plus it would be better if you guinea pig it for me )

Sound nuts?

 

[Neil E.]

It would be better if you guinea pig it for me.

I will have my carb sorted before you ride your new 2012 GasGas.