Lifan KPX Throttle Response / possible detonation

[JerryHawk250]

Originally Posted by MotoJane

I picked up my KPX 250 a couple of weeks ago and I'm having the same issues as others with the ping/click during acceleration. I don't hear it at speed or idle just when I'm going through the gears. It can be loud so with a helmet on I have no issue hearing it. I checked the provided manual and this bike has no gulp screw. No adjustment screws at all that I can see on the 2023 KPX 250. Anyone find a solution to this issue? I only have like 50 miles on the bike. I contacted Venom the folks I got the bike from with zero response.

You will need to contact American Lifan. They will either send you a programmer to reflash the ECU or have you send in the ECU for them to reflash.

[Ratbagger]

Originally Posted by JerryHawk250

You will need to contact American Lifan. They will either send you a programmer to reflash the ECU or have you send in the ECU for them to reflash.

I just contacted them and they told me to send my ECU to Venom Motorsports.

[MotoJane]

Well bummer on sending in the ECU. I just purchased this biking knowing about ECU issues with the bike. When speaking with the sales guy at Venom I asked if they would put the latest ECU into the bike and was assured it would be included. I need to call them, this isn't adding up. The throttle will give some slight hesitation and I know that points to the ECU or adjust the throttle. I've checked the throttle and it's fine, no major slack or kink. Well, heck.

[Megadan]

Originally Posted by MotoJane

Well bummer on sending in the ECU. I just purchased this biking knowing about ECU issues with the bike. When speaking with the sales guy at Venom I asked if they would put the latest ECU into the bike and was assured it would be included. I need to call them, this isn't adding up. The throttle will give some slight hesitation and I know that points to the ECU or adjust the throttle. I've checked the throttle and it's fine, no major slack or kink. Well, heck.

Venom bought up a bunch of stock due to EPA regulations causing many of Lifans bikes to not be legal for the immediate future until they can pass certain regulations. You likely got shipped a bike from that pool of vehicles with an older ECU and Venom was simply not aware of it because they knew all of the bikes they were shipped had the upgraded ECU, and yours simply didn't.

[MotoJane]

Well after many, many attempts to have someone anyone over at Venom contact me it's a bust. My KPX 250 is a lemon and the company just isn't getting back to me on this issue. I called all last week, called this week and they keep telling me "someone" will contact you and they don't. At high idle the bike sounds like there is sand in the motor and when I drive it the bike knock/pings as you get down the road. I'm afraid it will leave me on the side of the road so I don't go far from home. I haven't even got the bike past 45 mph. I wouldn't in fear of my life. I have changed the old and put all the proper oil in the engine. I did find some flakes but the oil wasn't that bad. I think this thing is going to seize up while riding. I did ask them about the ECU and the customer care woman on the phone told me the bike was too new and it has the latest ECU flash. I guess I'm going to sell this junk online as scrap. I'm out over $3,000 buck.

[PeanutRG]

Originally Posted by MotoJane

Well after many, many attempts to have someone anyone over at Venom contact me it's a bust. My KPX 250 is a lemon and the company just isn't getting back to me on this issue. I called all last week, called this week and they keep telling me "someone" will contact you and they don't. At high idle the bike sounds like there is sand in the motor and when I drive it the bike knock/pings as you get down the road. I'm afraid it will leave me on the side of the road so I don't go far from home. I haven't even got the bike past 45 mph. I wouldn't in fear of my life. I have changed the old and put all the proper oil in the engine. I did find some flakes but the oil wasn't that bad. I think this thing is going to seize up while riding. I did ask them about the ECU and the customer care woman on the phone told me the bike was too new and it has the latest ECU flash. I guess I'm going to sell this junk online as scrap. I'm out over $3,000 buck.

You don't have a lemon and it's not scrap. You should upload a video of the noise so we can atleast hear it. The engine will quiet down as you break it in. Everything you've said is normal within spec.. I have 600 miles on my kpx and iv been running 90 ethonal free gas. Every once in awhile I also get a slight ping. Ecu has been sent in already.... it's normal. These are small thumper engines. They're going to sound like a well oiled sowing machine.

[JerryHawk250]

MotoJane, Another possibility is that the Valves may need adjusting. Even though it is a new bike, As many of us know on the forum. Most of these bikes come from the factory with valve gaps set to tight or even too loose.