Hi all, new to the forum. I have a 2013 Sportsman 500. Since new it has been a little hard to start. I took it in under warrenty and the tech adjusted the throttle adjustment and the idol. That worked alright for about a month. Unfortunatly it is worse now than it ever was. In order to get it to start I have to give it a bit of gas and then to keep it running I have to keep some throttle untill it warms up. I have checked the throttle adjustment and it is good. The original choke would not and never had stayed out when pulled. This I thought may have been a large part of my problem. I tried ajusting the nut that was supposed to tighten it up and hold it out, but it still just sucked back in as soon as I let go of it no matter how much I turn that nut. So last night I put a new choke cable on it and it now stays out as it should. However it did not solve the problem. It seems to only make a differance when it is pulled out about 3/8. It will then rev the engine slightly. Pulled any more it will kill it and any less seems to do nothing. So, I am still not sure it is working 100%. I have adjusted the idol up some, and that helps with the starts, but as soon as it warms up the idol is shooting up to high (1800 RPM) and I have to crank it back down. I cant seem to find a happy medium with this machine. It never sits for more than a week without running. And once it gets warmed up it runs and starts great. I currently have around 2000 miles on it. I have thought about cleaning the carb, but I dont think that is the issue since it has been like this since new, although it has gotten progressively worse over time. I have not had the valves adjusted so I am thinking about doing that tonight, but am not sure the exact process. Mainly on how to get it TDC without a recoil start. Do you think a valve adjustment could even be causing this issue? Any help or info would be much appreciated. I hate the idea of taking this to the stealership, but I am running out of ideas now.
Thanks

 

If you're sure on the throttle slack it's no more than 1/8" then no harm checking the valves,but sounds like either an air leak somewhere,leaking intake manifold,head or base gasket. A leak down tester can tell if this is the problem.Plus on fuel,I'd always have some kind of ethanol treatment/stabilizer in the tank even if it only sits a week or so. Problem could still be carb related if the idle shoots up after engine is warm. The BST40 carb is kinda tricky especially on the float adjustment,plus if the dealer hasn't been through the carb I'd check it out. Here's a good posting on this carb that's used on a Ktm,but basically the same Mikuni. Gives a good deal of info on cleaning plus float level adjustment. The BST-40 Bible - ADVrider I'd save the carb for last and check the valve clearance first. Pull the spark plug,since you don't have a recoil starter. Then pull the valve cover and head side plate to reveal the cam sprocket. Bump the starter until the cam sprocket alignment pin is close to the top center of the head,then you can physically turn the sprocket and chain to tdc. You can pull the 14mm timing bolt on the stator cover if you wish to check for the tdc mark,but not really that necessary "IF" the alignment pin is dead center of the head.Valve clearance should be .006 for the intake and exhaust. Most times they will be spot on or even a tad loose on the feeler gauge. P.S. Doesn't happen often,but if the pick up coil under the stator cover is out of range (.025-.040) from the raised tab on the flywheel,this can cause hard starting also. Most are gaped pretty wide from the factory and wouldn't hurt to "gently" tap the pick up coil bracket inward a tad also. Even a simple thing such as this may help starting.

 

Thanks for the info. I try to get to the valves tonight. If that makes no change I will tear down the carb. I will post back with any updates, questions. Thanks again.

 

Thank you all for your input. I have finally fixed this machine. I went ahead with the valve adjustment last night. Not really that difficult to do. A little tight getting to a few bolts but not to bad. Anyway, my intake valves were a little tight. The exhaust valves were spot on. I loosened up my intake valves to the .006 and put everything back together. I did not think it would make a differance at all. To my surprise, no choke, no throtle, and just a very quick touch on the key and she fired right up and held steady RPM. I had to turn idol down once it warmed up because I had had it set real high to help with the hard starts. I set it at 1200 RPM shut it off and let it cool down for a couple hours. Went back out and it fired right up again and ran great. I checked it again this morning after sitting in 30 degrees all night and again fired right up no choke no throttle. This machine has never started this easy. Not even the day I picked it up from the dealer. What an amazing differance.
Not that I needed it, but I figured I may as well check my choke again now that it was running well. Sure enough my choke is now responsive throughout the entire pull. BONUS!!!
So to sum it up. If anyone is having an issue with hard starts, I would suggest adjusting the valves. It may not be everyones issue, but it was mine and well worth the effort just to check. I wish I had done this job months ago. The manual said to adjust at 100 hours I believe. Mine currently has 150 and just a touch over 2000 miles.
Anyway, thanks again and hopefully this will help someone else in the future.

 

Glad you found the problem. Doesn't happen often,especially on a 2013 model as most 500 owners don't even have to touch the rocker arm adjustments for quite a while. You just got one that might have been set too tight from the factory.Probably assembled on a Monday or Friday..