2nd trip out with a 99 sp 500 after acquiring it, 1st trip ran great and 1st day of this trip ran great (some mudding but huge rainstorm 15 miles back to campsite). I did notice some water in the airbox the start of day 2 so drained it good and off we go. 2 hours of riding went fine, then after a small amount of mud and muck it started to bog way down just above idle. Some but not much junk in the airbox again so I drain it and the float thinking something got thru. No better and ended up towing it back to the trailer. Have since found how the junk was getting in, gasket not on the front of the airbox all the way... But now I am stuck. I have taken off and cleaned the carb twice, completely disassembled too. Air/fuel screw is about same spot is was to start 3 turns out. Cleaned the airbox out and cleaned/reoiled the Uni filter. All this and it runs pretty much the same, will idle fine, little touch of the throttle fine, but more throttle and it bogs way down. Choke is no help, actually kills it.

Any votes on the next step and where I go from here??? Another trip in 2 weeks and really need it for that.

Thanks!!!

 

make sure you have at least+only 1/8 play in your thumb throttle,adj. is 4" up the handlebars,it can make it run bad if its too loose................

 

Did you spray carb cleaner through all the jets and the holes they came out of ?sounds like a piece of dirt in the main jet.Oh yeah in my expeirience, the air fuel screw should only be about 1 and 1/2 turns out.

 

Drain carb in clear container to see if fuel is water contaminated,also remove fuel line,crank to see if pumping ok,check for water. Have had several this summer blubbering from water.

 

Checked the throttle cable, no slack there, just as snug as it is on my 450.

Here is also what I did today.

Just put in a new plug and fuel filter to see if that helped at all, no change. Old plug is black from what looks like carbon deposits but overall not too bad looking, no idea how old that one is. gas was put in prior to the 2nd day's ride from the same station that I filled at the prior day and ran pretty much a full tank from there as it was empty when we first got there. I may drain the tank to see if that makes any change. Not really a backfire at all, sounds like it wants to when I throttle it up but never pops. Vent line looks ok, no woosh when I take the cap off or even if I hold my hand tigh on the filler opening, seems to be venting ok. No better when I manually choke it, in fact I think it is a little worse but for sure no better. Actually got too close and fully choked it with my hand and got a shot of fuel when it killed, normal???

 

First time I cleaned I'll admit it was a quick half a** job, 2nd time it was very thourouh. All the jets cleaned with fine wire and extra long sprays of carb cleaner. I thought main jet too so spent extra time on that. I'll give it a try with only 1.5 turns to see if that helps at all. Dumb question but would that thing back out on it's own and make a difference in performance that quick??? The 3 turns it is at right now is about where it was when I first took the beast apart.

I think I'll try draining the fuel completely and start with fresh gas, maybe some water entered the tank somehow. Seems that the fuel pump is pumping, from dry it took maybe a couple seconds for it to fire and idle.

You guys are the best with advice!!!!!!!!!!!!!

 

Maybe WRONG,but still sounds like water somewhere?

 

Kinda sounded like that to me on the trail also so thinking it was in the float bowl drained that but if it is in the tank that wouldn't have done anything. It is draining now and when the tank is empty I'll run and get some fresh gas to see if that does the trick. Fingers are crossed XX

 

UPDATE I drained the tank and put in new fuel, ran for a while to make sure the old was out of there and same running condition.

There was alot of talk on hilifter about a junk cam so I figured I better check it out further. I am not feeling much air blowing back out the carb like someone mentioned if the exhaust valves aren't opening up. I then went on to take off the valve cover, kinda late and I couldn't get a great look at the cam itself so I watched the valves for movement as I pulled the recoil. I can see the intake valves open but by sight I can't see the exhaust valves move at all. I'll admit I don't have a ton of experience with these motors but I would think you can notice some movement while the motor turns over, wouldn't ya??? I am assuming the cam is shot with what I have seen, but I'd like to know what you guys think.

That being said what do you guys think I should do, replace with stock popo cam or something else. If something else any recomendations.

Also while taking off the valve cover I bumped the spark plug wire and it moved a little out of the boot, thinking WTH, I pulled on it with very little effort it poped right out of the boot. So it really makes me wonder if I have 2 problems cam and plug wire. No idea how long it has been like that in 2 pcs.

 

I may just go with a new (used) motor, by the time I get a cam-gaskets-rockers (guessing bad too) and still only have a 500 non HO motor. I have found a couple 2001 HO motors for $400-600. Big question is the stator and carb usable off the old motor. I am told by both sellers they will be but i'll need to jet the carb.

Is the motor swap out too bad to do??? Then I'd have an extra motor too if I ever wanted to build it up. What do you think guys??