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Discussion Starter · #1 · (Edited)
Gonna try to make up a "Beginners" checklist of things to check before spending the huge bucks on takin your beast in..... Can also save a lotta searching...

1. Fuel Filter (Swirl Filter)... First and foremost the most common issue. Some replace it with an in-line filter and eliminate it. Spectre 2220 is one some use. At most auto parts stores. You'll find pros and cons to it if ya just search it on here... Search term fo Swirl Filter should get ya plenty.

2. Fuel Pressure.... Supposed to be 42psi... To check... Get a gauge ,any gauge that shows psi. I used an oil pressure gauge on a brass T, one fuel line goin in and one goin out. Un hook the fuel line coming off the Fuel Injector, and the one off the Fuel Pressure Regulator. The one that points at you. Gonna have to loosen the 2 bolts that hold the tank on to raise it up a bit. Hook the lines up, clamp em with a hose clamp. Turn the key on.. The gauge should show in the area of 42psi. Start it up and make sure ya are holding a constant pressure of 42. If not.. Fuel Pressure Regulator or Fuel Pump Problems most likely. http://www.ltr450hq.com/forums/engine-efi-drivetrain/40354-get-new-fuel-pump-100-dollars.html

3. Fuel Pressure Regulator... Looks like a pet cock, mounted under the tank. If ya take your seat off, look under the tank. There she is.... All I have done in this case to clean is, drain gas, do the normal needed to get tank off. 2, 8mm bolts hold it on there. Blow into it (with your mouth works) If you can blow through it, its hung open... Not what ya want. If ya cant blow in it, thats what its supposed to be. The diaphram is a common problem on these and can not be replaced.

4. Fuel Pump Filter..... Take the fuel pump off. Then take the 4 phillips head screws off the pump. Pull apart gently. Theres a rubber gasket ya dont wanna disturb. On the bottom of it is a small screen lookin filter. It just pulls out. Clean that baby up if ya got ANY trash in it. This one got me.

5. Spark Plug... This ought to be self explanatory (I hope)... Although I replaced mine with an Iridium plug. Make sure ya get the lil cap nut for the top of the plug.... My shop gave me the plug without it and I had to get one. If all ya see is a threaded top ya need the nut gidgit... Also the plug cap is known to pop off. Push it down on there till ya feel the click.

6. Wiring... Take all the front plastic off, start it up and get to (lightly) tuggin on wires, shaking , wiggling etc. Try to track somethin down that way. The Key Switches have been known to cause an issue here. Pay special attention to that area. Any spliced items like your aftermarket kill switch or start button. Make sure ya look at them. I just went ahead and re-taped, and put new connectors on em.

7. Air.... Make sure your filter is clean and installed properly... Also check the tubes from the back of the throttle body-- "carburetor"-- and make sure they are clamped on there good.

8. Tip Over Sensor... I pull it off while its started and flip it upside down just to make sure its working properly. Some folks have ran into this problem. Some also take it apart to silicone it open where it will wont shut the fuel offf when ya roll over. (also to prevent a possible problem).

9. Bad Gas... This probably needs to be a bit closer to the top of things to do because it is rather easy to do. Water in gas is a major pain in the ass cuz its overlooked and can be forgot about. Erratic also....

10. Throttle Position Sensor... This is a bit more advanced and I put it towards the bottom due to that. I used the service manual to do this and would 100% endorse you do the same. This is just another issue that can be a headache.

11.If you have a PCV do not enable the "rev extension" in the software.

12. Injector and Injector Filter.... This one has got a lot of us... The easy and most common way is to take it off, spray carb cleaner in through the bottom. Reverse the way fuel goes in essentially blowing the junk out the way it came in. Also, spoke with other people and they used air also. Hook a 9 volt battery up to the terminals. That will open the injector (you will hear a click).. Blow air through the bottom, back flushing..Only hold it open for a few seconds at a time or you will burn out the injector. There is a little filter on the injector also. I have cleaned a couple of them and you just have to be patient as this could ruin the injector filter. The lil black round thing on the top of the injector that looks like a phillips head comes out and is a screen filter. You can look down in there and see it and clean it without taking it out if you chose to. I take it out to make 100% sure.

13. If your quad is getting hard to start or needing to roll start it, DO NOT IGNORE. Valves on intake side are most likely tight and need adjustment. Exhaust side rarely need adjustment but the intakes need it much more. Dirty Filter and FTM (failure to maintain) will cause this to be needed more often.

14. Timing.... If you recently did a build, adjustment, or had a buddy fix this or that and now it won't start or backfires or won't take the gas. Check it. It's rather easy and ya can also knock out a valve lash check at the same time. Check your manual for this. I'm not sure but there may already be a write up on this process. Any time these quads fuel system is taken apart, its just short of a guarantee some craps going to get in the fuel system.

15. Programmer..... Just Try It.... This is coming from personal experience twice. I have has 2 go bad on me. It began to just out of nowhere and unpredictably cut out on faces of jumps and wherever. If its possible, unplug your programmer and try it without. Mine was a pc3 both times.


Now this is just what I have done in the past and in no way am I as good as most of these other dudes on here.... I got 99% of this from here and just compiled it in one big post to make it easier to track down..... I completed all these tasks with the minimal items I have in my lil garage. All but the pressure gauge, it was free to check em all too!!!. Replacements another story!!! ENJOY!!
 

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Discussion Starter · #7 ·
Heard Panty hose works pretty good too... Never tried it but its a thought. Coffee Filter is too slow n a T-shirt might work too???? The glass filter on got on my in-line gets shat in it a lot!! Between the gas can sittin up empty or the fuel pump, who knows where the lil grains of sand come from!!!
 

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Discussion Starter · #36 ·
Added a #12....
 

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Discussion Starter · #39 ·
Read the post, but I would start with the injector and fuel filter. If you have a programmer, unhook it and try that.
 

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Discussion Starter · #43 ·
My guess with the limited info...... Valves... As cqr said we need a lil more info. Can you ride it after it starts? When it starts, you hit the gas it dies? Will it take any throttle? Air box lid off? What recent work was done? You do all the work or has it been molested before you? Would love to help!
 

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Discussion Starter · #55 ·
Nick, send me a pm and I may be able to help you. Prob be able to text you a bunch easier.
 

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Discussion Starter · #61 ·
Why did you have the cam chain replaced? Any other parts replaced at the same time? Tensioner is not the greatest system on these beasts. What were you doin when this happened? Idle OK? Need more info.
 

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Discussion Starter · #64 ·
Also, no need for both filters. Pick one or the other. Since the dealer put a new swirl in it, run it and put the in line back. Is it throwing any codes when it's acting up? On the far extrem side of ideas----- my buddy had a issue similar and it was a head gasket that was leaky and wouldn't act up till pretty warm. Only way we caught it was on a whim checking radiator. Water was fine in the bottle.
 

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Discussion Starter · #77 ·
TPS....... Swap out the whole throttle body off the other one and try it. I had something similar on one I worked on. Had an extra throttle body with a tps on it, threw it on and fixed it.
 

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Discussion Starter · #90 ·
Start with the fuel. Do you still have stock filter or in-line? Get to the 1st post and start with all the fuel related ones.
 

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Discussion Starter · #92 ·
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