Bogging and loss of power please help

[patrickmeikle1]

Hi my name is Patrick I have just bought a Kawasaki Ninja ZZR250 - 2002. It was bought from a mechanic who completely cleaned the carbs, new battery, cleaned spark plugs, fairly new tires. The bike only has 10,000km

I have been warming up my bike and riding and it has been going pretty well until recently when I approached a stop sign and I went to accelerate in first and it started bogging and died.

Even after warm ups this has happened. I notice sometimes I lose power even when riding 50km/h (30mph) with 5000rpms.

It usually happens when I try to leave a stop and even at full throttle I have NO power and it feels like the engine is flooding when I pull on the throttle. APPLYING the choke when this happens does help (which makes me think it normally needs more fuel)

I am fairly certain it is a fuel problem perhaps a vacuum problem. I tried using PRI and RESERVE instead of ON, no fix. I think the carbs are filling up too slowly tbh.

Thanks for the help!

[csmith12]

Welcome Patrick!

There are some really smart wrench turners here. I bet they will have a list of things to check for you real soon.

I just hope you don't have to remove the carbs again to check those diaphragms and slides.

[Lazarus]

Greetings. Most will say the mechanic didn't clean the carbs as well as he said. Though you stated you have been riding the bike pretty well until the issue started. Have the needles been shimmed? Idle mixture screw plugs drilled out and adjusted on the carbs? Sounds like the problem could be lean mixture from idle and into midrange ,as you hinted at, being due to the carbs being lean from the factory?

My thinking is a mechanic may not do those "mods"? Specifically the idle mixture screws.

[RacinNinja]

If applying the choke makes things better, it's lean.

Try cracking the gas cap to see if the issues goes away during a ride. Don't do this with a full tank, I'd say half tank or less. If it does, you have a plugged vent in the cap.

[Alex]

/moved to pre-gen tech

[patrickmeikle1]

So 1) I tried opening the gas tank right after it happened this morning and no "woosh" sound that would be responsible for a tank cap vacuum problem.

2) The choke helps but it doesn't do much! I think it just helps because more gas is getting through and the rpms are way higher. So i think it may be a bigger problem than just running lean.

3) I talked to the guy who I bought it from and he is going to have a look today. He mentioned the fuel filter may need to be replaced. Said he cleaned the plugs and they should last 20,000km minimum

I'll let you guys know after tonight. Thank you! I am just hoping this has nothing to do with poor compression $$$$

[jkv45]

Because you paid to have a "mechanic" fix it I wouldn't do anything except take it back to him and tell him it's not fixed.

Sounds like the carb was not cleaned or adjusted properly to me.

[patrickmeikle1]

So the guy I got it from came over and changed the fuel line and fuel filter. runs perfect now. The filter was pretty dirty but the line has a slight kink in it. Hopefully it doesn't hAppen again. It seemed weird to be a carb problem because it could get gas at high rpm fine just not low. Strange

[RacinNinja]

Originally Posted by patrickmeikle1

So the guy I got it from came over and changed the fuel line and fuel filter. runs perfect now. The filter was pretty dirty but the line has a slight kink in it. Hopefully it doesn't hAppen again. It seemed weird to be a carb problem because it could get gas at high rpm fine just not low. Strange

Sounds normal for a fuel flow issue to me.

Slow speed/idle jets are high in the float bowl.

Choke and main jet are deep in the float bowl.

Low fuel level means the idle and low speed jets aren't getting fuel while the high speed jets and choke are.

A kink in the fuel line is no good. It needs to be shortened or re-routed so the kink goes away.