KLX-140L won't go past 5mph

Hello All, I'm new to this forum but hope to get to know it! :bonk:

So, I was riding my KLX-140L after doing some small jumps, and all of a sudden, I had a loss of power, to the point where the bike could only go 5 mph in any gear. :excuseme:

I turned the bike off and started it again, and still had no power, so I pushed it back to my garage ( I was in my backyard/orchard ) I unscrewed my oil cap, and smoke poured out of where the oil should be, ( I had the correct amount of Oil in the bike ) I let it cool down for about an hour and started it again, and I could get to about 7mph, not really any faster.

Before the problem, I had had trouble shifting out of neutral, but then I rode for 2 hours and it ran perfectly, jumped perfectly, went fast, etc ( it was riding VERY good )

When I'm in neutral I can rev the engine perfectly, ( so I don't think it's the throttle cable ), when i shift into gear is when the problem starts.

Another odd thing is that once I'm moving in first or second gear, I can ride at extremely slow speeds without the bike stalling....... normally at around 5 mph the bike would struggle then stall - but now it doesn't sturggle at all to go 5 mph.... any thing past 5 and well you can't get there

I tried to explain my prob as best as I could, my neighbor thinks it could be a loss of compression or a problem with the C clip on the carb.... ( The carb needle did have to be replaced 2 months ago )

The bike is only 5 months old, and just has weekend riding on it ( it's basically new ) so I don't think it could be a compression prob,

Any help is MUCH appreciated!

I'm not a 140 owner but I'm going to take a stab. If the engine revs good without a load and the bike in neutral, It could be the carb. If the C clip came off the needle, it would most likely fall further into the main jet causing the engine to starve for fuel under load. How does the clutch feel? Can you push the bike in gear with the clutch lever pulled in? How much free play is in the cable or lever before you feel resistance? You pushed it to the garage so the brakes aren't dragging. Start with the carb. Welcome to the Best section on TT. Go Green :excuseme:

OK, so I went over the whole bike today

1st, I checked the air box, and the element is perfectly clean, so thats not it

2nd, Checked the carb, the C clip IS on the carb, so thats not it

3rd, I tried to ride the bike and it acted exactly the same as yesterday :excuseme:

Basically, it rides like I have the choke engaged when it's not engaged, it feels like the gas/air mixture isn't right - which would obviously be a carb related prob, but I wen't over the entire carb and it seems fine

I then turned the choke on to try and ride, and it struggled horribly but didn't stall, so I turned it off after 20 feet.....

I went over the entire bike and it seemed fine - my ( old school ) grandpa thinks that it must have some dirt stuck in the fuel line somewhere, but I can't check that - so I'm probably gonna have the dealership come out and get it :smirk::foul::foul::bonk::bonk: I hate what they charge!

check and make sure sure you dont have a vacuum leak between the carb and engine. might be a crack in the rubber or something like that. Did you take the carb apart and blow out all passages with carb cleaner? Can you see through all the jets?

Wasnt there a post a while back about the rubber cap on the intake side deteriorating & causeing problems? Might be worth a check - quick & easy.

Pull apart the carb and clean out the main and pilot jets they clog easily, had this happen several times to mine, till i switched to the 24 mm carb

check all the electrical connections. If you have some dirty or corroded connections it may get enough juice at idle but not enough when at higher RPM's.

Get a small tube of dielectric grease from the hardware store and put a gob on every connetion including frame grounds.

Have you replaced the spark plug?

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