2005 BF 750- Engine loosing power

[Agustin AC]

Hi ppl, I've been reading the forum for some time, and find it extremely useful.

This time I decided to register in order to request some advice from the more knowledgeable people around...

I have a 2005 BF 750. Full HMF exhaust and K&N air filter.
I am having problems with the engine. Some times (not always) it will be hard to start. When running, sometimes it loses power, seems like one of the cylinders stops working, and after a while, it will start working again. When going downhill, the problem will worsen, and one of the cylinders will not work, making a very noticeable power los, but after giving it some gas, it will start working again, and the power will be back.
It backfires when going downhill or under load, but the power lose is not constant. Its like an On Off situation.

I have taken it to the Kawi dealer 3 times, and they have not been able to fix it.
At this point, I'm ready to change any part that could be the culprit.

Any suggestions?

[NMKAWIERIDER]

Originally Posted by Agustin AC

Hi ppl, I've been reading the forum for some time, and find it extremely useful.

This time I decided to register in order to request some advice from the more knowledgeable people around...

I have a 2005 BF 750. Full HMF exhaust and K&N air filter.
I am having problems with the engine. Some times (not always) it will be hard to start. When running, sometimes it loses power, seems like one of the cylinders stops working, and after a while, it will start working again. When going downhill, the problem will worsen, and one of the cylinders will not work, making a very noticeable power los, but after giving it some gas, it will start working again, and the power will be back.
It backfires when going downhill or under load, but the power lose is not constant. Its like an On Off situation.

I have taken it to the Kawi dealer 3 times, and they have not been able to fix it.
At this point, I'm ready to change any part that could be the culprit.

Any suggestions?

Hi Agustin AC, welcome to the site. What you are describing is typical for a low fuel supply to the carbs. This happens for several reasons but can usualy be traced-out. It could be fuel pump, cracked or leaking vacuum lines to the pump, plugged fuel valve, plugged screen on intake in tank. Also, if the carb bowls have water in them, it will act this way too. So drain them just to be sure. Also, if the check valve that is inline between the tank and frame is stuck, it could allow the pump to put a vacuum on the tank until its so much, it can't get enough fuel. That's easy to check, just loosen the cap and run it. If the problem stops, its the check valve. The others will require a little more testing and checking. If you can get to the fuel supply line as it attaches to the carbs, pull it off and crank it over pointing it at something to catch the fuel. It should be a good and solid streem. If not...work yourself back.

Of course make sure the valves are set correctly

[Agustin AC]

Thanks for the input. Will do the advised tests, and will report back.

[zip1]

sounds like a fuel filter