Hi. I've got an 04 ltz400. I just rebuilt the engine top and bottom. I put a 440 big bore kit in it. The bike has an hmf slip on exhaust and I'm running an open air box.
When I fire it up it idles fine but when I try to accelerate it pops and backfires. If I accelerate to quickly it dies. I cleaned and fully rebuilt the carb. The float measures within spec. It was originally running a 130 main jet. I replaced it with a 142, 146 and 150 with little difference. It smells like it's running rich with the 150 installed. I've played with the mixture between 1 and 3.5 turns on each jet change in 1/4 turn increments. I'm running a 27.5 pilot jet. The valves have been adjusted and shimmed within specs.
I did notice that the needle jet that the main screws into was bent when I rebuilt it but I replaced it with a new one. There is also a small exhaust leak where the slip on exhaust pipe connects to the header pipe. I would think if that was going to cause any issues it would only be on deceleration though. My issues are definitely with acceleration.
I bought this bike with a broken case due to a thrown chain. I never saw it run so I don't know if it was having issues before hand but given that they were riding it when the chain broke the case I would assume it was running good. Help would be greatly appreciated. Thanks
When I fire it up it idles fine but when I try to accelerate it pops and backfires. If I accelerate to quickly it dies. I cleaned and fully rebuilt the carb. The float measures within spec. It was originally running a 130 main jet. I replaced it with a 142, 146 and 150 with little difference. It smells like it's running rich with the 150 installed. I've played with the mixture between 1 and 3.5 turns on each jet change in 1/4 turn increments. I'm running a 27.5 pilot jet. The valves have been adjusted and shimmed within specs.
I did notice that the needle jet that the main screws into was bent when I rebuilt it but I replaced it with a new one. There is also a small exhaust leak where the slip on exhaust pipe connects to the header pipe. I would think if that was going to cause any issues it would only be on deceleration though. My issues are definitely with acceleration.
I bought this bike with a broken case due to a thrown chain. I never saw it run so I don't know if it was having issues before hand but given that they were riding it when the chain broke the case I would assume it was running good. Help would be greatly appreciated. Thanks