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What did you do to your dirty bike today?

Carb/brake cleaner and a guitar string is what I use. I also blast cleaner through all of the carb bodys orifices until I see it coming out the other end, not just jets. If its your first time, good way to actually see how a carb works. Finish with a blast of air. Some times the dried fuel residue forms a thick film and the guitar string scrapes/releases it when simply spraying cleaner wont. In another thread I think it was Kazman who suggested a torch tip cleaner which I thought was brilliant.

One from Homedepot for $4 is on my tool add list

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THANKS everyone!

The carb had some dried residuals in it from being stored by the previous owners so I took it apart and cleaned it out. The KTM carb was much less intimidating than I had expected. Got some B12 carb cleaner and computer compressed air and cleaned everything up. Checked my floats and diaphragms and they are in perfect shape. Needles, pilot and jets are clean as a whistle.

Put it back together. It runs good now! I need to tweak the mixture as I don't have it just right and it hesitates and stumbles off idle which makes me think now it's running rich so I'll toy with it this evening.

Once I have it dialed in I'll toss a new plug in as well.

Last thing I need to do is replace the rear shock as it's too soft of a spring (suggestions?) and put on some new front brake pads. If I get around to it I'll flush the rear brake fluid as it's the only fluid that hasn't been touched yet.
 
Off idle stumble on those is usually the size of the pumper jet/duration rather than pilot sizing. Check the interwebz, I seem to remember people switching the pump jet from a 50 to a 70 and getting good results.
 
elemetal said:
Off idle stumble on those is usually the size of the pumper jet/duration rather than pilot sizing. Check the interwebz, I seem to remember people switching the pump jet from a 50 to a 70 and getting good results.
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It was running perfect before it got clogged up. Running the JD jet kit with pipe which is ideal for the EXC450. I'm thinking the A/F mixture screw might be off as I didn't mark how far out it was turned.

We'll see tonight how it runs leaning it a bit more with the A/F mixture.

Also the TPS (i'm assuming that's what it is --the electrical connection at the top of the carb on the driver left side) was put on exactly the same spot but I tried to match up where it was clean vs dirty to get nearly where it was positioned before. If the A/F doesn't help the stumble then I will mess with this connector.
 
Are you checking the hesitation/bog/stumble on the stand? If yes, all bikes will do that if you twist the throttle fast enough, so make sure it happens when riding before trying to do anything about it.

I've always heard that you shouldn't ever remove the TPS, though I think there is something in the manual about how to set it. Still, I'd disconnect it and see if it runs better. You can ride with it disconnected just fine, but maybe not if it's adjusted incorrectly. I dunno, but I'd try disconnecting it.

All of my FCR bikes haven't needed any of the accelerator pump tweaks because of bog, except for my old yz250f. I did the o-ring/wire around the linkage and ended up soldering the leak jet fully closed and that took care of it. Think I also ground the rivet on the diaphragm, but it's been too long. Any FCR would probably benefit from the o-ring/wire mod, but there's no universally correct leak jet size, so buy a few smaller sizes and try them out if disconnecting the TPS and the o-ring doesn't fully clean it up.

Of course all of this is moot if it really was running perfect before it was clogged. It means you still have some cleaning to do. And to CJ's points, you really need to stick something in there. Chemicals alone is like trying to wash your car without touching it, you can make it better, but it's never really clean unless something is touching it. Sometimes I'll just buy a new pilot jet because they're cheap and the tiniest layer of film makes a difference.
 
byke said:
Are you checking the hesitation/bog/stumble on the stand? If yes, all bikes will do that if you twist the throttle fast enough, so make sure it happens when riding before trying to do anything about it.

I've always heard that you shouldn't ever remove the TPS, though I think there is something in the manual about how to set it. Still, I'd disconnect it and see if it runs better. You can ride with it disconnected just fine, but maybe not if it's adjusted incorrectly. I dunno, but I'd try disconnecting it.



Of course all of this is moot if it really was running perfect before it was clogged. It means you still have some cleaning to do. And to CJ's points, you really need to stick something in there. Chemicals alone is like trying to wash your car without touching it, you can make it better, but it's never really clean unless something is touching it. Sometimes I'll just buy a new pilot jet because they're cheap and the tiniest layer of film makes a difference.
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It was on the stand but when you chop the throttle from an idle it will bog and sometimes die but it did this when off the stand as well as when just on the kickstand. Roll on gently and brap it while engine speed is up it runs smooth (no hesitation, all 4 strokes are smooth--no thumping). Idles smooth as well (no thumping, purrs like it originally did). KTM manual also states mixture is too rich if this bogging coming off throttle happens. When the bike was on the stand previous to this whole debacle it ran just fine.

I cleaned the pilot jet as suggested and after running briefly it clogged again and that's why I took the whole carb apart. I cleaned jets and ports with carb cleaner and with some wire. I also cleaned the carbs with a q-tip, blowing out any residual with carb cleaner and then compressed air. Everything was spic and span after reinstall. All the o-rings were in excellent shape, along with the float/mechanism and the rubber diaphragms. The only thing in question is the TPS and the A/F mixture. Being it runs smooth at idle and while on throttle I'm thinking it is still one these these things not just right.

Vac lines were numbered and reinstalled in exact ordered. I sprayed carb cleaner around the carb and lines to ensure there were no leaks-confirmed no leaks.

Looking at the spark plug...the coloration indicates a rich condition but the plug is dry so not overly rich.

Reading up on the accelerator pump to see if there is anything there that didn't get adjust correctly when put back together. Thankfully I know it was running good before tear down so it's just a matter of fixing a few things that weren't precisely measured when disassembling.
 
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Micheal, I generally dont ever remove the TPS, just disconnect it when removing carb. When I do, I dab a mark on it and the carb to ensure its in the same spot. If you re installed it in the same place based on the visual cues, you most likely got it right.

Adjusting the fuel screw isnt rocket science. Fully warm the bike up and then lower the idle just above stalling (you may have to blip throttle occasionally). Then adjust fuel screw until you get the highest idle. Back off 1/4 turn. You are almost there. Make minor adjustments from there for best throttle response off idle. Double check by riding it and brapping off idle. Once you are satisfied, readjust idle screw. Done.

Re bogg on stand Byke was referring to. He meant riding vs stand. Most will have some bogg if going from idle to 3/4 throttle or more on stand. Wont do when riding.
 
OaklandF4i said:
Micheal, I generally dont ever remove the TPS, just disconnect it when removing carb. When I do, I dab a mark on it and the carb to ensure its in the same spot. If you re installed it in the same place based on the visual cues, you most likely got it right.

Adjusting the fuel screw isnt rocket science. Fully warm the bike up and then lower the idle just above stalling (you may have to blip throttle occasionally). Then adjust fuel screw until you get the highest idle. Back off 1/4 turn. You are almost there. Make minor adjustments from there for best throttle response off idle. Double check by riding it and brapping off idle. Once you are satisfied, readjust idle screw. Done.

Re bogg on stand Byke was referring to. He meant riding vs stand. Most will have some bogg if going from idle to 3/4 throttle or more on stand. Wont do when riding.
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I will take it for a ride before making further adjustments. It got late last night when I noted the bogging while hitting the throttle hard in neutral from idle and didn't want to tick off the neighbors further by riding around the neighborhood at 10pm. I imagine the a/f is off a bit still so I will use the aforementioned adjustment method. I'll also put a new plug in for kicks and giggles which should also indicate whether it is running lean or rich. I will also double check the TPS as it was dim lighting and could be off a millimeter in one direction.
 
Thanks for everyone's help. Bike is running pretty good now! I need to make some micro adjustments. It otherwise it's back to being a monster. New plug and some AF mixture adjustments helped.
 
Guoseph said:
Turn. On. Gas.

Just kidding. Floats sticking open is a lot more common than floats sticking closed. That being said I did have a float needle stuck in the closed position.

I am confused though, first you say it's not getting any fuel bu then you say it starts and idles somewhat, which would not be possible unless it's getting at least some fuel.
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Edited now that I see the issue is resolved.
Good news!
 
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Sharky said:
Edited now that I see the issue is resolved.
Good news!
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Thanks!

I am going to adjust the TPS tonight. Found the voltage it needs to be..pretty simple to adjust. It should resolve the last of the issues it has. Runs sharp now. Can't wait to get out on the trails!

EDIT***

Bike is running perfect. I got the TPS set correctly by equating the resistance between ground and the other two wires and it is spot on.
 
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Lunch Box said:
Great stuff, Michael. Love all the helpful folks here.
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Thanks. The folks here made it happen and gave me the confidence to take apart the carb.

I'm loading up the bike to go camping this weekend with it. Plan to adventure as much as possible. Minimum 100 miles of technical trails PLEASE!
 
Rode the old Warrior at Metcalf today after raising the front back up and putting the Banshee shocks in the front. Not too many people at the park as it still green sticker season. Was pretty dry and warm today. It runs ok but I think need to bypass the parking brake rev limiter, I'm losing power. Will fix it and the bent rotor next week and take it back out. Its pretty clear I am out of shape also I was hurtin after the first lap around trail 1 o_O' I got so used to the lowered Warrior it just 3 wheels everywhere now =/ until I get it slid anyway.

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Removed rear shock to get refreshed (new fluids/gas) and to get a new heavier spring install for my weight.

Should get it back in two weeks to get my suspension dialed in for the next few trips I have coming up!

Ordered a new front tire (Dunlop AT81), tubliss system for front tire, grips and safety wire, and misc parts.

Excited to take the beast out after it's set up again.
 
madsen203 said:
Removed rear shock to get refreshed (new fluids/gas) and to get a new heavier spring install for my weight.

Should get it back in two weeks to get my suspension dialed in for the next few trips I have coming up!

Ordered a new front tire (Dunlop AT81), tubliss system for front tire, grips and safety wire, and misc parts.

Excited to take the beast out after it's set up again.
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Curious who you took the shock to?
 
I started to button up the ATK for deep storage.
Ordered even more parts for the Mo Beta

Began the task of mapping out a dual sport ride to Carson.
 
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