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10/27/2015
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2014 yz250f
The bike runs as expected when I first get to a track. After 3-5 motos (5-10 laps each) the bike starts to bog hard while on the throttle in high rpm's. It does it without warning. If I let the bike sit for a day it runs fine again then 3-5 motos later it will start to bog again.
I've checked just about everything I can think of. Sparkplug, new fuel line, valve clearances are good (freshly rebuilt head on stock cams), piston/rings have less than 3 hours, and timing is good.
Weather does not change the outcome. This started in the dead of winter and the most recent time it happened was this past Sunday at Budds creek in the blazing heat.
Could it possibly be the injector or even the fuel pump beginning to fail? They're both pretty expensive so I'd rather not buy them without knowing for sure that they're the issue.
Any leads would be great!
The bike runs as expected when I first get to a track. After 3-5 motos (5-10 laps each) the bike starts to bog hard while on the throttle in high rpm's. It does it without warning. If I let the bike sit for a day it runs fine again then 3-5 motos later it will start to bog again.
I've checked just about everything I can think of. Sparkplug, new fuel line, valve clearances are good (freshly rebuilt head on stock cams), piston/rings have less than 3 hours, and timing is good.
Weather does not change the outcome. This started in the dead of winter and the most recent time it happened was this past Sunday at Budds creek in the blazing heat.
Could it possibly be the injector or even the fuel pump beginning to fail? They're both pretty expensive so I'd rather not buy them without knowing for sure that they're the issue.
Any leads would be great!
Regardless I ordered a new fuel filter. Hoping that's the issue and that it's nothing major. But I'm worried it could be the pump because I run VP fuel every few months and I've heard that stuff eats up in tank pumps. Just not knowledgeable enough with the electronics to be certain.
The Shop
I'm having sort of similar issues with a 2014 YZ450F. Couple of things related to my experience:
Fuel pump filter replacement is a bit of a pain in the ass. There's a good video for disassembling the fuel pump on youtube.
The electrical connection to the fuel pump is kinda suspect. I've had it come loose twice (I think). It's not cool - but it is a straight shut down and won't start back up kind of thing. I read that some people replace the stock connector with new, individual connectors.
I had some really head slapping problems as a result of not having the black clamp that belongs on the fuel line connection to the fuel pump. That 10 dollar part disappeared somewhere along the line and cost me several weeks of riding time before I figured out it was missing.
After that first bog it starts to bog down then regain power sporadically whenever the engine is under load at half throttle or higher. I can hold it wide open with the clutch pulled in and it'll rev to the limiter with zero issue or cruise around not giving it much throttle and be fine. It's almost like the fuel can't keep up with the demand.
If I let the bike sit overnight I can go right back out and it's good for another long day of riding. I have a private track I go to throughout the week that I'll spend maybe 2-3 hours at a time riding. It has never had this issue there despite that I ride the bike longer than I would at a track in those 2-3 hours (because of split classes at public tracks).
But, if I'm at a public track I'm always there from 10:00am-5:00pm and the issue doesn't start until around 3:00pm or later. I've had this issue for the last 3 times I've taken the bike out to public tracks. All 3 are in vastly different areas so I know it's not the climate.
Post a reply to: Bike bogging at the end of the day