I have a 2007 AC 500 4x4 Manual, its a great machine, just clicked over to 500 km's ( 350 miles) and there are a few things im a little concerned about.
1) I switched to synthetic oil at about 200 kilometers and seems like right after that the oil got realy black really fast...im just at 500 kms now and im going to do an oil change cause it just looks really bad......they say to have the valves done at about 200 kms.....could this be the cause?..gas milage....about 120 kms per tank so far....(75 miles)....15 MPG in canadian gallons...a littel under the average i think for this machine.

2) when i rev it up at an idle to about 4000 rpm it belts out a nice little cloud of black smoke..never did that before...

When it hit about 400 km's i put in a K+N filter and got a jet kit for free...the filter was fine....i could not tune in the jet kit properly so i took it out for the time being.....but was told that the 136 jet was a beter choice for a jet then the stock 140...so ileft it in....but changed the needle back to the stock one...and dialed in the air screw as good as i could....and thats all the monkeying around i have done with it.
it starts good in the warm or cold.....tops out at 93 KPH (56.6 MPH)...when it starts from cold with teh automatic choke it runs great..then it starts to idle rough...kinda blurpy......when i let off the gas in slow speed down hill..its blurpy again....at slow speed its just not smooth enough.....carb??
any ideas??

 

interbizman,

Your Carborator should have a slow speed and a high speed jet. According to my service manual which covers through 2006 models you should have the following for a 500:

Main jet - 138
Slow jet - 40
Pilot Screw - 1 3/4
Jet Needle - NFKG
Starter jet - 85

I see yours is a 2007 and I do not believe they made much if any changes to the 500 lineup between 2006-2007. From what you are describing it sounds like your main jet is OK but your slow jet needs adjusting. I do not know much about jetting but I can tell you that if you look at your plug color it will tell you if you are running too lean or too rich.

Also, I have been told by others that if you run a K&N filter to put a "sock" over it if you live and or ride in dusty areas. I guess they are a pre-filter sock that helps keep small particles out of the engine. You also have to clean the filter and sock often in dusty areas.

As far as fuel econmy goes it is my understanding that in order to get more power you need more air (K&N filter does that) and more fuel. So you would be decreasing your fuel economy.

On a side note what is a liter (or gallon) of fuel going for there in Canada eh?

SJ

 

Thanks for the info.....

The plug shows black, kinda heavy with carbon.....running rich in the lower rpm by the looks of things....should i screw in the air mixture screw a little more....its about 1 1/2 turns out right now....

 

Interbizman,

On some carborators the air/fuel screw gives (screw out) or takes away (screw in) air. On others it actually feeds fuel from behind the pilot jet. It can even do both. I am not sure which of these it does on the Kiehin carborator. I suspect both air/fuel.

In your case I think what you are turning is the Pilot Screw. You have to access it from beneath the carborator. It should be located just in front of the float bowl towards the engine side of the carborator. To adjust it you screw it in, gently, until it stops, do not force it. Then screw it out 1 3/4 turns.

When I have taken this screw out while cleaning the carborator on my TRV and I reinstall it I go 1 3/4 turns and never have to touch it after that. So try taking it out another 1/4 turn OR screw it in and then out 1/ 3/4.

Remove and clean your plug and run it for a little while and check the plug again.

SJ

 

I did the air screw and it smoothed out the idle alot...seems to be better.
The only thing that remains is the fact i still get a little bit of black smoke if i open the throttle from an idle.
I jsut did an oil change on it and the oil got dark right away....could this be piston ring blow by, or should the valves be adjusted???
The manual says the valves should be done after the break in period......but would that cause the oil to get that dirty that fast?...im worried that there is a problem with the rings....and if i leave it too long i might be replating the cylinder as well as doing the rings.....its only got 400 miles on it....would a compression test tell the story if there was a ring problem?

 

A compression test would tell you if you only that you are losing compression not the why. You could loose compression because of rings, valves not seating, blown head gasket ans such.

I believe that if you have put many miles on with it running rich you may have allowed more of that black carbon (like what was onthe plug) to build up inthe combustion chamber. It does this no mater what you do but dies it faster when it is running rich.

I would suggest you put some fuel additive in for 2-3 tanks that cleans the carb and combustion chamber. I use SeaFoam to treat my fuel all the time. You shouldn't have to with the prices we are paying but... Seafoam should clean your entire system carb, jets, combustion chamber, valves, etc. You may also want to change your spark plug. You will need to use a high concentration to clean carbon inthe combustion chamber. Instructions are on the can and you can find it at almost any Auto parts store or larger gas stations.

SJ