Hello,
My neighbor has a 2000 yamaha beartracker 250 that is having issues. It is idling at much higher rpms only in neutral and a tad bit in 1st gear. If I turn the choke on the rpms go down a little. I did a rebuild kit on the carb and checked for air leaks, I didn't see any signs of air leaks, the boot was good. It has a brand new intake manifold, but either way I put some silicone gasket maker on the carb part that goes into the boot to make sure it has a good seal. I can't figure out what's wrong with it at this point, I've had the carb off multiple times and it appears fine, but I'm sorta a noob so if something very minor was out of place I probably would not have noticed. Any help would greatly be appreciated!!

 

Did you use a good rebuild kit with all new gaskets and diaphrams? Instructions for adjusting and setup should be in there. A trick for checking air leaks is to speay some WD40 all over the carb and intake connections and see if rpm changes. Sounds like carb is not adjusted or you have an intake air leak!!

 

This is good information as it is pinpointing that the AFR (air/fuel/ratio) is off and definitely sounds to be running lean. But also consider it might be that fueling is low, with normal air flow, causing the lean condition. I'm certainly not an expert with carbs but there still could be the condition where corn fuel sat for too long and caused varnish. Maybe a jet is still slightly clogged not allowing proper fueling. I would also consider having the fuel tank removed and cleaned out as a good first step towards resolving a fueling issue.

 

This is the one I used,
And as for that wd40 trick, I did that with but with carb cleaner, would carb cleaner still change the rpms? I figured it would. I adjusted everything so that is sounds good. When it is running in 1st gear at a normal rpm, it sounds to be running very healthily, but who knows, i could be wrong.

 

That sounds possible, I though I replaced all the jets in the carb with that rebuild kit though, are there other internal jets that you can't replace or something like that? And as for the tank, I never thought of that! I will look into it and do that, can I save and reuse the gas in there though? The tank has been emptied and re filled multiple times since this issue has started.

 

Your centrifugal clutch, as the name implies, comes in with increased revs. As your engine is revving too fast to start with, the clutch will be partially engaged all the time, so stick it in gear and that clutch has to slip or you would be off down the road, which drops the revs a bit. Nowhere in your posts have you mentioned setting the idle speed stop screw. That is how you set the idle speed in the first place. Many times when I have cleaned a carb out, the idle speed shoots up, why? Because someone has increased idle speed, via stop screw, to compensate for a partly blocked carb. Once clean, that setting is too high.

 

Ok, I never thought of that, next time I get a chance I will adjust that screw and see if that helps, that makes a lot of sense.

 

clogged jet, varnish buildup or crud in carb should have been solved with his carb "rebuild"...poor fuel in the tank or poor fuel flow could definetly be the problem. I would only assume that folks having engine issuses would begin with fresh fuel. Having owned a 2002 bear tracker, I know how easily it is to have an air leak in the rubber intake manifold, thus the WD40 trick while running should detect a problem.

 

carb cleaner would work for that too right? I did it with carb cleaner and it made no change. I will try again next time I get a chance though

 

So, another thing I just discovered. It only idles high in neutral when the engine is warm. If it has been sitting for a day and is cold it doesn't start idling high in neutral until the engine is nice and hot. Does this mean anything to yall?