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Discussion Starter · #1 · (Edited)
Been chasing this issue for a long time on my 07 LTR. The Quad starts up and idles and runs strong. Like clock work after around 15-20 minutes of riding the engine starts bogging and acting like it’s not getting enough fuel or there is an air flow problem. If I turn the key off and then back on while the engine is still running and The quad is still rolling the problem temporarily goes away and the motor runs strong for a few minutes but then continues to do the same thing. It’s almost like when I turn the key off and on its priming the fuel pump. I can keep turning the key off an on like this on an all day ride but it’s super annoying. I’m about out of options here. The only other thing I’ll add is that sometimes it starts a lot easier when the key is turned on and the fuel pump is in the middle of its prime. The engine idles fine for as long as I leave it running, it’s not until I put it under heavy load after 15-20 minutes it starts acting up. I’m going to list what I have already replaced one by one to address the issue with no success.I’m hoping someone on here had similar symptoms and did something other than what I have tried. I even talked to Chris Borich on the phone and he is scratching his head.
The quad has a brand new fully built Turtle Race Motor with yoshi cams, new valves etc running VP 110 fuel.
replaced so far;
Replaced PC3 Brand new PC5
OEM Stator and pickup coil
OEM flywheel
OEM Injector ( multiple )
OEM fuel pump
OEM Fuel Pressure Regulator
OEM belly filter assembly
OEM Coil
OEM ECU
OEM rectifier /regulator
OEM Wire Harness
OEM TPS
OEM throttle body
OEM Air Pressure sensor
OEM Air temperature sensor ( inside air box)
OEM Gear position sensor
OEM Fuel Pump Relay
OEM key switch
New fuel lines
New NGK Spark plug
New cherry bomb
 

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have you tried to run with the fuel cap off?
 

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Discussion Starter · #3 · (Edited)
have you tried to run with the fuel cap off?
Yes sir, I changed the fuel cap altogether to make sure it wasn’t hydro locking and that didn’t fix it. After that I removed the fuel tank and low and behold the lower fuel line that feeds from the fuel pump to the inlet on the fuel pressure regulator ( petcock) had a significant kink in it. I replaced it with a new one and also replaced the upper fuel hose from the FPR outlet to the injector. So far so good. Rode for a solid 30 minute. Under heavy throttle and she’s running great. Now I have basically a brand new quad with all the new parts. It’s been to dealerships, engine builders and no one ever caught the Kink in the fuel line.
 

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@rickterscale77 I was going to say check the fuel lines after. These quads are built so tight its easy to overlook something.
 

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Discussion Starter · #5 ·
Yes sir not a lot of room under that tank and throttle body. Never cared for that design compared to fuel injections on the KFX 450 and late model Yamahas which are much simpler. Appreciate your help friend.
 

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Been chasing this issue for a long time on my 07 LTR. The Quad starts up and idles and runs strong. Like clock work after around 15-20 minutes of riding the engine starts bogging and acting like it’s not getting enough fuel or there is an air flow problem. If I turn the key off and then back on while the engine is still running and The quad is still rolling the problem temporarily goes away and the motor runs strong for a few minutes but then continues to do the same thing. It’s almost like when I turn the key off and on its priming the fuel pump. I can keep turning the key off an on like this on an all day ride but it’s super annoying. I’m about out of options here. The only other thing I’ll add is that sometimes it starts a lot easier when the key is turned on and the fuel pump is in the middle of its prime. The engine idles fine for as long as I leave it running, it’s not until I put it under heavy load after 15-20 minutes it starts acting up. I’m going to list what I have already replaced one by one to address the issue with no success.I’m hoping someone on here had similar symptoms and did something other than what I have tried. I even talked to Chris Borich on the phone and he is scratching his head.
The quad has a brand new fully built Turtle Race Motor with yoshi cams, new valves etc running VP 110 fuel.
replaced so far;
Replaced PC3 Brand new PC5
OEM Stator and pickup coil
OEM flywheel
OEM Injector ( multiple )
OEM fuel pump
OEM Fuel Pressure Regulator
OEM belly filter assembly
OEM Coil
OEM ECU
OEM rectifier /regulator
OEM Wire Harness
OEM TPS
OEM throttle body
OEM Air Pressure sensor
OEM Air temperature sensor ( inside air box)
OEM Gear position sensor
OEM Fuel Pump Relay
OEM key switch
New fuel lines
New NGK Spark plug
New cherry bomb
Do you have a programmer or tuner if so might be that that is messing up already maybe need to replace it I had a similar problem I had a programmer/tuner on mine and it would bogg out after 10-15 min of riding it then it wouldn’t wanna turn on then the red over heat light would pop up then go away i took my programmer off removed it cleaned my air filter and re packed sparks exhaust with the micro fiber patting and started running like a champ right after that & I’ve rode it hard after & runs great I run mine on 110 Sunoco fuel just that I haven’t add it lately but if you do have a programmer probably could me that it’s not giving the right amount of fuel to the injector or it’s giving way to much what I been told by a Suzuki technician/mechanic is tht those Suzuki ltr are jst best to run them stock with no programmers ever since I took mine off never had to deal with that problem again
 
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