[Will Goes Boing]

Hi guy, I have been off the bike for a couple of years and recently purchased my buddy's 2005 KTM 525 exc supermoto. I use to ride with him a lot when I had my wr250x and I've never seen him have any issues with the bike. He's had the bike sitting in his garage for a couple of years so the bike had some issues starting up. He cleaned the jets and the bike started up, but the next day the bike wouldn't start again.

So I took the carb off and brought it to a shop for a full deep clean + rebuild. Afterwards it was still a bit hard to start and actually died on me while I was riding on the freeway to work. Turns out I pinched the breather hose between the tank and the frame, so I replaced it with a new one + cut it shorter so now it routes under the tank. All is good there.

During that time I also took out the petcock to inspect it and found that it was ALL gunked up. I also emptied the tank and found this blob of dark brown stuff inside. Turns out my buddy accidentally screwed one of the fairing screws too deep and made a hole, so he filled it up with this glue. I think he squeezed a little too much in there and all that glue went into the tank.

I cleaned it all out, filled it up with premium fuel, got a new petcock. I also took the jets out and did a nice deep cleaning. The bike started with the 1st kick with ease, and the thing pulled like a mad banshee. WOO HOO! All good right?

WRONG

I rode the bike to work today and the bike just cut out while I was riding in the carpool lane. I was stranded on the side of the freeway until my buddy was able to bring me some tools. I looked in the fuel tank and there was some more of that brown debris in there. So I cleaned out the jets, and dumped out the old fuel. Put fresh fuel in there. Bike started right up and rode fine.... for about 1/2 mile until it sputtered and died again. I cleaned the jets out again and was able to limp the bike back home but it feels like it has no power.

The spark plug is new, but air filter is old. I'm new to carbs and this has pretty much been a nightmare for me so far. All of my friends who ride dirt bikes talk so highly about how awesome carbed engines are but I'm almost ready to give up on it. At this point I can't even take it to my KTM dealer which is located 2 mins down the street from my work. I was going to bring it in after work today to have them look over everything regardless but I can't even get the bike there.

Desperately need some help.

 

[SuvyBA]

Valves out of spec? Could be part of the issue starting up.

 

[Will Goes Boing]

Valves out of spec? Could be part of the issue starting up.

My buddy checked the valves when it initially wouldn't start, and he said everything was in spec. Right after I cleaned out the jets, the bike starts right away with ease. So at this point I know it has spark, valves are in spec, and compression should be good.

As I said I don't know much about carbs. As of right now the small and big jets are the only thing I've messed with. Today when it broke down on the side of the road, me taking out the jets and cleaning them made the bike start right back up. But after about 1/4 mile I would feel it lose power.

And it seems like the problem amplifies when I'm riding on the highway at a constant speed. When I'm riding around city streets/neighborhood where I'm constantly stopping and going, upshifting/downshifting it seems to run ok.

 

[GROOVY2]

likely just more crap in fuel - keep cleaning till its gone-

I have read Pinesol works to clean fuel type gunk but I have never used it
so I cant say for sure -

 

[Will Goes Boing]

likely just more crap in fuel - keep cleaning till its gone-

I have read Pinesol works to clean fuel type gunk but I have never used it
so I cant say for sure -

I have a new tank coming in on Friday and I'll be getting a new petcock to go along with it. In the mean time I'm going to take apart the carb and do another clean myself this time.

Could running too lean or too rich have anything to do with this? Also, the air filter is pretty old.... could that also be a culprit?

 

[Skully25]

when you say breather hose you mean the engine breather hose or the tank breather hose?

the gas cap doesn't have one of those check valves on top of it right... I kept chasing my tail once on a buddy's bike that kept stalling, it was fuel starvation because the ball in the check valve got stuck and created a vacuum inside the tank, so fuel couldn't flow to the carb.

 

[Will Goes Boing]

when you say breather hose you mean the engine breather hose or the tank breather hose?

the gas cap doesn't have one of those check valves on top of it right... I kept chasing my tail once on a buddy's bike that kept stalling, it was fuel starvation because the ball in the check valve got stuck and created a vacuum inside the tank, so fuel couldn't flow to the carb.

Engine breather hose. The one that goes from the carb to the engine. The initial incident with the highway break down was because of that hose being pinched, and it caused vapor lock. That time, the bike would start again after letting it sit for about 5 mins or so. I fixed that problem by replacing it with a brand new one and I routed it under the tank instead of having it jam between the tank and the frame.

As for the gas cap, it's just a basic one with a nipple. I did remove that hose though. I figured if it vents out it vents out. Or does that vent hose play a part?

Today.... the bike would not start up at all until I took out the jets to clean them. I just pulled the petcock and there aren't any debris/residue that I can see. Later I'm going to try to take things apart to see if there are any obvious signs of debris in other areas of the carb. I just hope I can put it back together!

 

[Skully25]

vent hose on the gas cap makes no difference, if the tank can vent that's all that matters, doesn't need to have a line on it.

if the tank keeps producing gunk I'd say make sure you clean it out or if you have a new tank on order that should get that out of the way.

I'd also try to get the carb cleaned with an ultrasonic cleaner, I think that's just about the only way you can be sure no dirt is left behind in any passages.

if the jetting was an issue it really needs to be off by a lot before you run into any serious operating issues. if the bikes runs fine and fires right up I wouldn't put my money on a jetting issue. sounds to me like it's just starving for fuel because of dirt and gunk keeps finding it's way to the carb.

 

[Will Goes Boing]

vent hose on the gas cap makes no difference, if the tank can vent that's all that matters, doesn't need to have a line on it.

if the tank keeps producing gunk I'd say make sure you clean it out or if you have a new tank on order that should get that out of the way.

I'd also try to get the carb cleaned with an ultrasonic cleaner, I think that's just about the only way you can be sure no dirt is left behind in any passages.

if the jetting was an issue it really needs to be off by a lot before you run into any serious operating issues. if the bikes runs fine and fires right up I wouldn't put my money on a jetting issue. sounds to me like it's just starving for fuel because of dirt and gunk keeps finding it's way to the carb.

Thanks for the help. I'll do some serious deep cleaning for the carb and replace the rubber hose that connects from the petcock to carb. That blob of brown resin I found in the tank has been in there for so long that when I tried to pick it up it kept crumbling in my finger tips. I think that stuff really wrecked havoc in there.

Would you recommend me try to put in seafoam to run it through the engine once I get everything going again?

 

[Will Goes Boing]

So as I was using compressed air to clean out the carb I noticed something..... There's this white grease on the right side where the rod joints with the side. Wouldn't that stuff dislodge and clog things up?

 

[goldenzim]

I think your problem is simple. It's a pain when your fuel system is contaminated but the solution is easy. I have just put together a custom bike. A cafe racer and I got this old tank from am 80's suzuki. Painted it to look sweet but the inside was full of shit. It clogged my carb up and my petlock and fuel hoses and - yeah... anything to do with fuel flow was gunked up. The fix : Clean everything. Install an inline fuel filter so at least your carb won't get clogged again. Many carbs have a fine filter installed on the fuel line connection point. Take that connector thingie off your carb and have a look. A new tank will mean no more contamination but clean all your hoses and joints too.

Don't start messing with jetting till you know your system is clean. Even a bike that is horribly jetted will still run and get you home.

 

[Will Goes Boing]

I think your problem is simple. It's a pain when your fuel system is contaminated but the solution is easy. I have just put together a custom bike. A cafe racer and I got this old tank from am 80's suzuki. Painted it to look sweet but the inside was full of shit. It clogged my carb up and my petlock and fuel hoses and - yeah... anything to do with fuel flow was gunked up. The fix : Clean everything. Install an inline fuel filter so at least your carb won't get clogged again. Many carbs have a fine filter installed on the fuel line connection point. Take that connector thingie off your carb and have a look. A new tank will mean no more contamination but clean all your hoses and joints too.

Don't start messing with jetting till you know your system is clean. Even a bike that is horribly jetted will still run and get you home.

Thanks for the pointers. I plan on doing exactly that. New tank, new petcock, new fuel hose, and I'm in the process of cleaning out the carb. Ill take your advice and take a look at that joint piece.... I know exactly what you're talking about. Lot of potential for debris to accumulate in that spot.

 

[Borg]

The white grease you see shouldn't be causing any harm.

It's above the slide.

Are all the vent hoses on the carb venting? Is there a catch can, or does it just run straight to the ground?

 

[Will Goes Boing]

The white grease you see shouldn't be causing any harm.

It's above the slide.

Are all the vent hoses on the carb venting? Is there a catch can, or does it just run straight to the ground?

All the hoses should be venting alright. They all go straight to the ground. The most concerning part is that the inside of the carb is pretty clean except for a few small specs of brown stuff. I was expecting it to have a lot of that brown residue from the resin to patch the tank.

 

[Borg]

I'd put money on the new tank/petcock fixing the issue.

 

[Will Goes Boing]

Alright guys, so yesterday I put on the new tank, fresh premium octane gas, tank has a new petcock installed already, and I gave the carb an extra deep clean along with new jets. The bike is doing this weird thing that it did before, where right when I start it up and have the choke out, it idles really rough. But once I push the choke back in, the bike idles faster and smoother.

Before I take it out for a test ride to see if the problem has truly been fixed, I was wondering if I should change the oil along with changing out the oil filters.

As mentioned, the bike has been sitting in my buddy's garage for 3 years, but prior to putting it away he changed the oil on it. I read up on how much oil to put in the bike and it seems like the general consensus is to have the oil level be at the halfway point on the glass window when the bike is cold. Do I check it when the bike has been sitting for say, a whole day? Or do I start the bike, let it run, and then let it sit for 15 minutes and that's when it should be at the halfway point?

Also just to confirm..... if my compression is bad, the bike would not run at all correct? I'm just trying to make sure I've done everything I possibly can do to make sure I don't get stranded on the side of the freeway again. It seems like every time the bike rides just fine around the neighborhood, but once I take it on the freeway that's when it acts up.

 

[GROOVY2]

If out side temp is warm and you start bike with choke ON it will likely run ruff - That is normal and to be expected -

engine smooths out with choke OFF that is normal and to be expected -

I would say ride it with oil it has in it a few times and then change it at some point -

Oil level can be checked in 15 minutes or Less - it does take a few minutes but usually under 5 -

the Freeway or highway and Not good test ride locations - ride around neighborhood or parking lot =

 

[Will Goes Boing]

If out side temp is warm and you start bike with choke ON it will likely run ruff - That is normal and to be expected -

engine smooths out with choke OFF that is normal and to be expected -

I would say ride it with oil it has in it a few times and then change it at some point -

Oil level can be checked in 15 minutes or Less - it does take a few minutes but usually under 5 -

the Freeway or highway and Not good test ride locations - ride around neighborhood or parking lot =

That's a little bit more settling as I wasn't sure if that was normal or not. In regards to location for bike testing..... I rode around the neighborhood for a good 30 mins with the bike running great that one weekend. And on Monday I took my bike to work, hopped on the freeway and within 5 minutes the bike crapped out on me while I was in the carpool lane. I had to make my way 4 lanes across during rush hour traffic with the engine dead. A few weeks ago when I first picked up the bike it did the exact same thing. Ran fine around the neighborhood, but crapped out on the freeway.

This time around I'm going to ride around the neighborhood much longer to test it out. I plan on taking my bike to a local shop just to have them look over it, but it requires me taking the freeway to get there. So I'm going to have a friend follow me in a car + I'm going to have my toolbox with me.

 

[Will Goes Boing]

So after all that...... now the bike is difficult to start up, and when I finally got it started and took it out for a quick spin, it ran like crap. Just sounded "off" and didn't have much power. I give up; gonna have it towed to the local KTM shop and let them figure it out. :headshake

 

[SuvyBA]

So after all that...... now the bike is difficult to start up, and when I finally got it started and took it out for a quick spin, it ran like crap. Just sounded "off" and didn't have much power. I give up; gonna have it towed to the local KTM shop and let them figure it out. :headshake

Let us know what the problem is when you get it resolved.