My new to me scrambler 500 will turn a new plug black in 5min run time. I have been through the carb, raised the needle 1 position, new air filter and still fouls plugs. I want to adjust the valves but can't find the timing mark through the hole. Is removing the pull start as simple as removing all the bolts and it comes right off ? Will there be oil in that case? This is my second season having quads and don't know much about them, but I am pretty mechanically inclined. Any other recomendations would be greatly appreciated.

Thanks,
Adam

 

Carb float on this model has to be set correct or you can have problems. Still a good idea since the machine is new to you to at least replace the needle and seat. Possible where most of the rich running is coming from. Look over this BST40 carb used on a ktm which is similar to yours. Shows how to set the float level correctly.https://www.google.com/url?sa=t&rct=...U2gGlaHJWSIlbA Really simple on finding tdc without having to look at the flywheel. Pull the recoil and watch the intake rocker arms as they go down and start to come up. Once they come up and the cam sprocket alignment pin is dead center of the head the piston is at tdc and valves can be checked/adjusted. They set at .006 intake and exhaust. IF you are uncertain you can just remove the recoil bolts and recoil,highlight the tdc mark on the flywheel,replace the recoil cover then use the tdc mark to align with the pointer on the recoil.

 

have you checked the air/fuel mix screw?

 

I have checked air fuel screw and it is out 2.5 turns. I pulled the cover and found the marks. There is a "T" and then 3 lines. Do I want to line it up on the middle line? I will check the float level again. Would the float level being off make it run that rich. It will turn a new plug black in minutes and black smoke out the exhaust and smells really rich.


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Sorry, just looked at the pictures you posted. So line it up with the "T" not the 3 timing marks right?

 

yes the T ...i think mine is out like 2 turns..you gotta read the carb bible if unsure...id start from scratch(stock) and work from there

 

No sense in taking a carb off and cleaning and adjusting over and over. You only need to pull a carb once,replace worn parts,especially the needle and seat as the needle tip can wear out over time along with the o-ring that holds it in place. Gas can bypass the seat around the o-ring causing it to run rich also. Here's a good Shindy carb kit made in Japan for less than what an oem needle and seat costs. New Shindy Carburetor Carb Kit Polaris 500 Scrambler 1998 2002 Sportsman 01 02 | eBay 2 1/4 to 2 1/2 turn out on the fuel screw is about right.

 

I bought that exact kit last night. hopefully it will be here by the end of the week.


thanks for your help,


adam