K75 Mixture

[hoodun]

My bike seems to be running a bit lean. It needs the choke on for a couple minutes when it starts (65 degree weather) or it will just stall out, even if I rev the gas. After it warms up it is fine. Its an annoyance that I would like to fix. I changed the fuel filter and it made no difference.

note: I just purchased this bike so I am not sure what has or has not been done to it.

[TimTyler]

It needs a tune-up.

Plugs, valve adjustment, TPS adjustment, breather hose, throttle balance.

Head to the library here and you'll have it running smoothly in no time.

[wmax351]

There isn't actually a choke on a K bike. Just a fast idle lever. It's normal for it to be needed for a while after startup.

[hoodun]

Good to know. I was worried about riding with the choke on. If its just a fast idle I should be fine riding with it in the half way position?

[wmax351]

Good to know. I was worried about riding with the choke on. If its just a fast idle I should be fine riding with it in the half way position?

Absolutely fine, though at the higher levels, and depending on your settings, it may prevent the idle switch from engaging. This prevents overrun fuel cut, which is a slight detriment to fuel economy. I use it when I am on dirt, as it prevents a sudden cutout of power in first gear.

[TimTyler]

Expect more backfiring on deceleration.

If its just a fast idle I should be fine riding with it in the half way position?

[hoodun]

There is definitely backfiring on deacceleration. I am going to give this bike a full tune up so hopefully that will make a big difference.

I feel like a fuel injected bike with sensors, etc., should generally start right up. My old r90 starts up with out the choke no problem and runs great. The weather is usually around 65 where I live... I only need the choke on the R90 when it gets to about 50. I spent a lot of time dialing that bike. I plan on doing the same with time K75. Ordered new plugs. replaced all the fluids, etc. Going to go through all that is suggested here, including valves.

The R90 and K75 are great contrasting bikes btw. The R90 is great around the city with girl on back. The K75 is perfect for the freeway and for short trips, and good for getting groceries in the city, with the saddle bags. I'm happy with both bikes. ...just got the K75 a couple weeks ago...

[argent brick]

My K75 has the same problems. I recently found an air leak on the vapor recover line between the fuel tank and the crankcase. Fixing that has made a huge difference. Does your bike die if you suddenly roll off the throttle?

Hey, wmax351, would you please explain about "overun fuel cut" for those of us that are still learning about K bikes.

[wmax351]

My K75 has the same problems. I recently found an air leak on the vapor recover line between the fuel tank and the crankcase. Fixing that has made a huge difference. Does your bike die if you suddenly roll off the throttle?

Hey, wmax351, would you please explain about "overun fuel cut" for those of us that are still learning about K bikes.

Fuel injected vehicles cut fuel on overrun, which is basically idle throttle position, with higher than a certain rpm. I think it is 2200 for a k bike. It's called over-run, as you are actually doing work on the engine, rather than the reverse. The throttle is only open enough to give power to run the engine at idle, but the engine is turning much faster. A good way to understand what exactly is going on is to ride with the throttle position switch (only on the 2 valve bikes) disconnected. You will notice that it doesn't decelerate as quickly when you let off the throttle and coast.