Hello,

I'm riding an AKT 250 Adventour through the Andes and notice power loss at 9000 feet (2,800m). I see an obvious screw for the idle adjustment but I do not see where the fuel/air mixture valve is.
Any help would be appreciated!

Matt

I don't know this bike and no idea what Carb it's using. I'm guessing it's some sort of small Chinese CV carb? ... so should be a Fuel Screw (AKA Pilot fuel/air adjustment screw) on there somewhere.

These screws are often hidden under float bowl, possibly recessed, hidden with tin cover blocking access. (easily removed)

To Note: It's not unusual to lose A LOT of power at high altitude. Even with proper jetting and with Fuel Screw leaned out sufficiently, you will still lose A LOT of power. It will get worse as you go higher.

And F.I. system may run cleaner up high, a F.I. bike will lose just as much power as Carb ... all due to lack of Oxygen at higher altitudes.

Adjusting the Fuel Screw will help starting, idle and throttle response off idle, but will NOT increase power. (Sorry!)

Ok thanks for the help! The AKT does have a small metal plate cover. Perhaps it's located behind that. I had in mind today to remove the air filter sponge as well. Maybe that would help a little?

I plan to ride to Huaraz Peru in the next week which is at 10,000 feet. Right now in Quito the bike really struggles on hills.

matt

Here's some pics

I would not leave off the "Air filter sponge". Clean it, lightly oil it and put it back on.

My guess is that Carb will have to COME OFF the bike to really work on it.
A leaner (smaller number) main jet may also be required as well as leaning out Pilot Fuel screw
(if you can find it!)

I would buy two SMALLER main jets. Buy one that is ONE SIZE smaller (lower number), and a 2nd that is TWO sizes smaller than stock main jet. Just go one step at a time. Also, look at spark plug ... if it's BLACK ... then you need to install a smaller main jet. Once back at SEA LEVEL, re-install standard main jet again. A very clean or white spark plug means a LEAN condition. Not good. A black plug means too rich. A light tan or medium tan/brown is ideal.

Once again, bike will not gain power but will run cleaner, get better fuel economy and carburate better overall. Combine this with a properly adjust fuel screw and you'll have it running at its' best. But at 4000 meters, no 250 will make much power.

Beautiful area, very remote. Have fun! Ride Safe!

I slid out the air filter (which is a flat cartridge) and the performance improved back to normal. The air intake is a box under the seat which seems to be well protected...

As far as jets is this a standard carb that I could find them anywhere? This is a colombia bike and if I have to get the parts from colombia that would be no good...

Since I plan to stay in Huaraz at 10,000 for awhile I would be up taking it apart when I get there and changing the jets.

But right now to remove the carb I would have to remove the tank which is not ideal.... and I will be going down to sea level, to the coast, on the way to Huaraz.
Matt

I doubt you'll easily find jets for that Carb ... but WHO KNOWS? Chinese bikes seem to be EVERY WHERE now throughout S. America! So give it a try!

Yes, your bike will run stronger with no air filter in place ... but over time dirt and dust with RUIN the engine. I'm sure you knew this. BUT .... maybe there is a way to retain the air filter but to OPEN UP the air path before the air filter. Many times there will be baffles and such to reduce intake noise. Sometimes you can open up the air box to let in more air ... all this with air filter still in place. This would help! MORE AIR = More power!

If you see bike dealers or bike shops along the way, I would ASK! they may be familiar with your Carb and have jets. Or, may be able to CALL another dealer in the area to help you out. Also, it's quite possible that many of the Chinese bikes use the SAME carburetor. (just a guess)

Also, if you end up in one town a while you could EMAIL (or call) a dealer in Colombia and have them send parts to you by bus. This is a popular way to move light cargo and not expensive.

If you are riding alone on wet, deserted mountain roads with no dust from trucks or buses, you may get away with riding with no air filter ... but it's risky. I would not do it. Try to open up air box before it reaches the air filter. (better flow)

I was at Toby Shannon’s ( Around the Block Tours) place in Huanuco last year and he serviced my AKT and changed the jet for me. He has a good shop , mechanics and knowledge I believe.

if removing the filter increased the power that is a sure indication the filter needs cleaning. no filter will do permanent damage to the engine.