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just recently went through this myself

when I cleaned out the FCR carb on both mine and my buddy's 450's. Don't forget to pull the float bowl out and remove the plunger/stoper that goes into the carb. On the EXC IIRC there might be a screw at the bottom where the plunger goes - this will allow you to remove a small screened area where the fuel enters the carb from the tank - clean that thoroughly. Also spray plenty of carb cleaner down the inlet of the fuel entry (where the tube from the tank goes to the carb).

I removed an impressive amount of gunk there in my cleaning regimen and if that wasn't done you might have bit of gunk re-entering your carb jets after you clean it.

Also needed to reset the float bowl level for some reason on my SMR after sitting up for a few years. Go figure.

But seems as how you are taking to dealer this is rather moot besides to see if that was included in your regimen.
 

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Discussion Starter · #22 ·
when I cleaned out the FCR carb on both mine and my buddy's 450's. Don't forget to pull the float bowl out and remove the plunger/stoper that goes into the carb. On the EXC IIRC there might be a screw at the bottom where the plunger goes - this will allow you to remove a small screened area where the fuel enters the carb from the tank - clean that thoroughly. Also spray plenty of carb cleaner down the inlet of the fuel entry (where the tube from the tank goes to the carb).

I removed an impressive amount of gunk there in my cleaning regimen and if that wasn't done you might have bit of gunk re-entering your carb jets after you clean it.

Also needed to reset the float bowl level for some reason on my SMR after sitting up for a few years. Go figure.

But seems as how you are taking to dealer this is rather moot besides to see if that was included in your regimen.
Thanks for the pointer. I actually managed to ride the bike a whopping 25 miles to the ktm shop without it dying on me. It felt a bit boggy and felt low on power, but it got me there in one piece. I'm going to give the shop a call later to see what issues they found. The guy said from the way it sounds its mostly a jetting issue.
 

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My thoughts are if the jetting was ever right on the bike chances are it still is. :hmmm: KTM RFS are gloriously notorious for not having to mess with the jetting once it's right. :D

Now, if it's running like it's too lean having gunk reenter the carb will block a jet/orifice and in effect lean it out. Don't recall in the thread if you replaced the jets or not. but I will say that with pilot jets (ESPECIALLY) oftentimes if they are gunked up it's better to just replace the jet than it is to attempt to clean it out. I've had that experience myself more than once - and reminds me I need to order another one. :D

So another item to do when a bike has been sitting up is to just replace, with the same size jets (ASSUMING it was correct to begin with) and perhaps a needle.

What about the accelerator diaphragm? When do you have the stumble and burbles? WTO is it OK? (I suspect it is - that's the main jet and is easily cleaned). Partial throttle? On acceleration? Holding steady?

At this point replacing the jets, needle, and pump diaphragm is little money, just a bit more effort than what you've already put in, and IMHO worth doing before a trip to the shop to spend $$.

It's yo thang - do whut ya wanna do. I can't tell you how to do yo do.
 

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Discussion Starter · #24 ·
My thoughts are if the jetting was ever right on the bike chances are it still is. :hmmm: KTM RFS are gloriously notorious for not having to mess with the jetting once it's right. :D

Now, if it's running like it's too lean having gunk reenter the carb will block a jet/orifice and in effect lean it out. Don't recall in the thread if you replaced the jets or not. but I will say that with pilot jets (ESPECIALLY) oftentimes if they are gunked up it's better to just replace the jet than it is to attempt to clean it out. I've had that experience myself more than once - and reminds me I need to order another one. :D

So another item to do when a bike has been sitting up is to just replace, with the same size jets (ASSUMING it was correct to begin with) and perhaps a needle.

What about the accelerator diaphragm? When do you have the stumble and burbles? WTO is it OK? (I suspect it is - that's the main jet and is easily cleaned). Partial throttle? On acceleration? Holding steady?

At this point replacing the jets, needle, and pump diaphragm is little money, just a bit more effort than what you've already put in, and IMHO worth doing before a trip to the shop to spend $$.

It's yo thang - do whut ya wanna do. I can't tell you how to do yo do.
Thanks for the pointers. I actually did change out the jets as well as the needle.. I think that might be the reason why it's running like crap. The bike didn't die for the long ride to the shop so I think the underlying problem was resolved. The pilot jet is the same size, but the bigger jet is a different size. The c clip on the needle is also in a different position.

The shop is a little slow on getting to my bike. I made the mistake of telling them to "take their time". :rolleyes2: hopefully they get to it today.
 

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Discussion Starter · #25 · (Edited)
So I got the bike back today. They said it was just a jetting/tuning issue where it was running wayyyyyyyyyy rich. They explained that was the reason why the bike was hard to start + ran like crap. It looks like when I changed out to a new tank, new petcock, cleaned out the carb it fixed the issue with the bike shutting off while riding. They did a compression test and everything was good, valves were a bit out of spec so they fixed that as well. The guy said he had to go down quite a bit on the size of the jets.

The bike felt pretty solid on the way home and started up really easily. Only thing now is it seems to be quite a bit low on power compared to before. Prior to it dying the 2nd time on the freeway when I thought I had everything fixed..... the bike pulled HARD. Right now it just seems very "tame" when I get on it. Noticeably slower.

Keep in mind I'm very new to carbs so this might be a stupid question. But is that because of the change in jet sizes? The original pilot jet was 50 and the big jet was a 180 or 182. Now the new pilot jet is a size 40 and big jet is 170.

Edit: And threads are always useless without pics. So here's one of the bike after new plastics and decal kit.

 

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uh, yeah...that's a big change in jetting!!!! Original for these carbs are: pilot 42, main 178. I've a hopped up SMR with a 42 pilot and 185 main. I'd say, if it doesn't pull as hard maybe go up on the MAIN jet (that circuit runs WFO throttle) and see how it runs. If a bike is too lean it loses a lot of HP. But I'd think since your pilot is pretty close you should be almost there. Try a bigger main jet (put the 180 back in and DON'T mess with the pilot!) and see if the WTO is stronger. If it is keep going until at WFO it runs like crap, then back down. Then at partial throttle openings (25% to WFO) you can adjust with needle/clip positions.

A KTM 450 at WFO should make you hold on for dear life (well...mostly...it pulls very strongly and you shouldn't give that up).

JD Jetting also has a kit for KTM's that's just spot on. Once I did that and the accelerator pump mod my 450 woods bike was spot freakin'-on-electric perfect in all temps.

But I'm glad it's all taken care of and you can certainly file this under lesson learned. :clap:

Now go get that HP back...
 

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Discussion Starter · #27 ·
uh, yeah...that's a big change in jetting!!!! Original for these carbs are: pilot 42, main 178. I've a hopped up SMR with a 42 pilot and 185 main. I'd say, if it doesn't pull as hard maybe go up on the MAIN jet (that circuit runs WFO throttle) and see how it runs. If a bike is too lean it loses a lot of HP. But I'd think since your pilot is pretty close you should be almost there. Try a bigger main jet (put the 180 back in and DON'T mess with the pilot!) and see if the WTO is stronger. If it is keep going until at WFO it runs like crap, then back down. Then at partial throttle openings (25% to WFO) you can adjust with needle/clip positions.

A KTM 450 at WFO should make you hold on for dear life (well...mostly...it pulls very strongly and you shouldn't give that up).

JD Jetting also has a kit for KTM's that's just spot on. Once I did that and the accelerator pump mod my 450 woods bike was spot freakin'-on-electric perfect in all temps.

But I'm glad it's all taken care of and you can certainly file this under lesson learned. :clap:

Now go get that HP back...
Thanks Rocksmoker, I appreciate the advice. I found out from my buddy that he had a JD jet kit in there before and the needle was what really makes a difference. I'm going to buy another one and do some experimenting. :thumbup:
 

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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.
Did u check diaphragm on accelerator pump. I have an 03 525 exc. I know about everything about 525's and my cuz owns a ktm shop. Hmu if u need any questions answered.
 

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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.
Hi
I suspect the petrol in the tank went flat, in other words lost its octane rating, and in the process some of it solidified into hard blobs. You need to flush all of that out. The other thing you could do, is put an in line filter between the fuel tank and carburetor.
This will save you having to keep stripping cleaning the carb.
Regards
Allan
 
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