Mech

Good work. I like that you cleaned and inspected the drive system and didn't just condemn it out of hand, and then you got it working. Even if it does need a bit of work after a while it lets you test everything else. It's important we use our discretion when choosing what needs replacing. That's good work..

When a carb starts backfiring it's normally because the mixture is too lean. It can be caused by badly retarded ignition timing or tight valve clearance, but mostly it's a lean mixture, especially if it does it more as you open the throttle more. The flooding out the overflow is a different problem..

Well the circumstances should be considered here.. It takes about 20 minutes before the trouble starts manifesting.. A blocked fuel tank breather could cause problems like that. A blocked vent normally causes a fuel shortage as the tank starts to get a vacuum in it and the fuel stops flowing. It can happen though that a blocked vent can cause the carb to flood, but it's normally when the bike gets parked in the sun and the tank pressurises. It is possible though that in this case a blocked vent, despite the fuel being taken out of the tank as the engine runs, is actually letting the tank pressurise as the engine or sun warms the tank up. Check the fuel tank and the carb breather hoses are attached to the right place, and that they are clear.

Yeah could be that Ww. If the carb's just been off then, yup, the rubber could be split. Good idea. Most of the time though, bad vacuum effects the idle more than it does an engine at revs. If they will start and idle, (even with a vacuum leak), then they will generally rev up and run pretty much as normal. There are exceptions though, such as the carb moving in the rubber, or the rubber flexing and letting air in.

I think there's a manual in here called "Polaris 1999-2000 Service Manual" that does all the models, including that Magnum 500.. If I didn't get it from here, let me know and I'll upload it to the service manual section.

haha.. I'm not a mechanic that remembers model specific details.. I keep finding that a name in one year, or market, can mean something different elsewhere or in another year. You know what I'd say though.. manual transmission, suspension/drive as simple as your riding will tolerate, carby... japanese. Red is good.

Not speaking to Greg or Gw here, because I can see and know they are both thorough and logical, but for those that do struggle with electrical problems.. A "voltage drop test", is the way to find bad connections. Look it up and understand how it works. We have to look for the bad connection with full load on the connection. We can go around watching milli-voltages, or checking resistances, and never find the bad connection (and associated voltage drop), if we are just depending on our super precise digital meter.. And for the same reason, most of the time it's best to use an old fashioned test light (with a bulb that uses a bit of power), to quickly trace power, rather than the digital meter. And the other thing that I suspect causes a lot of difficulties and reluctance to do all the tests needed, is people try to work on their quad with all the body work on it. Most body work comes off relatively easily if the bolts are greased. Whenever a quad needs some work under the body work, it's nearly always worth taking the few minutes to pull the plastics off. And it's true of electrical as well as the fairly mundane, such as valve adjustment.. And it's a good time to check the wiring for chafing etc..

Yeah.. I put heavy loads on front and rear, and can still lower myself down, or back up, on hills to steep to trust your footing on. That's one of those old fifteen speeds with three reverses.. haha.. It is a bit excessive but I have really steep land and it's brilliant.. And I've tried other quads here as I worked on them.. Hard to beat the creep along speed. The dairy farmers though on rolling land, and all the guys at the beaches, they all love hondas..

I think you're right Chuckster.. Honda are super simple and super reliable.. If it wasn't for the really steep land i live on, (which the suzuki super low is really handy for), I'd have a honda,.

Good work Greg.. Those mud wasps are little mongrels aren't they ? And so fast to get into things !

Are you sure the fuel isn't leaking between the float needle seat and the carb body ? Does that bike have a fuel pump originally ? Is that carb made to run with a fuel pump ? If not, then the carb on it will have big float needle jet, and it will struggle to seal against even one pound of fuel pressure. The normal pressure for a bike with gravity feed is only about, er.. probably a quarter pound of pressure. Water gives 0.4Lb of pressure for every foot of height, and most fuel tanks are only a few inches above the float needle jet, and, fuel is lighter than water and gives less pressure.. The fuel pressure is very low. You can get different sized float jets for carbs and depending on the fuel pressure they are designed to operate with. the size of the jet can vary by a factor of three or more. Using the wrong size float jet can cause flooding or fuel starvation.. If you are sure the seat to carb body is sealed, then I'd recommend resetting the float height to specs and rigging up a gravity fuel feed temporarily(without the pump), to see if that cures the problems

Yup, check the power supply and the earths to the cdi unit, and check/clean the main switch and the kill switch contacts. Clean if possible(kill switch) or check with an ohm gauge.

Yup, that sounds like not enough freeplay in the throttle cable..

I see people saying it shares it's running gear with other makes/models.. Not sure which makes or models though.. Some people also seem to be saying it is made in Texas.. In which case you should be able to get service/parts.. And someone said they got a parts manual by asking the manufacturer.. It was an old link though..

Depends if you want sport/performance, recreational riding, or work-horse, and the local terrain makes a difference when choosing. I think most of the jap bikes are very reliable.