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Gas Leak From Carburetor Bowl/Drain

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I just got done fixing a bad hanging idle on my 08 YZ250F via searching this forum, but I now have the most terrible bog (actually stalls at times) when going from no throttle input to WOT, a sputter when riding, and fuel is leaking from the carburetor bowl area. Also, while idling if I pull out the choke the bike immediately dies. A smooth roll on to the throttle eliminates most of the bog, but the bike will still sputter some while riding and fuel still leaks.

The leaking fuel does not seem to be coming from any hoses, but rather the bowl drain or something in the vicinity. I think I put the slide plate on correctly and I do not think I over tightened anything reassembling the carb.

Any ideas what happened or next steps? I had ZERO bog issues prior to the carb cleaning. From searching the forum I am going to:

-Check float height

-Ensure drain tube is not damaged

-Ensure drain screw is not cranked down too much

-Clean float needle seat, float needle cavity, and pivot pin with steel wool

-Verify no damage to float needle tip

 

Here is a description of what I did to resolve hanging idle, just in case it could've come from that:

-Performed proper steps to evaluate fuel screw setting and stepped up the Pilot Jet from a 45 to a 48

-Took apart and cleaned the carb as per the Rocky Mountain video: https://www.youtube.com/watch?v=c60emySUo64&list=PLCnll6zz9R_cqGc48XzDu-wevHPpKOC__&index=4

-Replaced slide plate o-ring (previous one was rotted and in pieces)

-Installed new fuel elbow connector and o-rings (previous one was bent and o-rings had rotted)

-Tightened header bolts

-Installed clamp where exhaust silencer meets header

-Installed new easy adjustment fuel screw

 

And pics of leak and how the slide plate is orientated:

You can easily see all the moisture and droplet of gas in this pic:

IMG_4295.thumb.JPG.4f0d3bbe47679531e1036476dc87d434.JPG

This is how I have my slide plate oriented:

IMG_4260.thumb.JPG.2e4b87ed207dd6e0ff36c2d5ce5a4cbc.JPG

 

 

 

Edited by scr200

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8 minutes ago, Krannie McKranface said:

Your leak is at the apump cover, and most likey you lost one of the two orings that go in there,,,which would also cause your quick throttle bog

 

http://www.pbase.com/jdjetting1/keihin_fcr_manual_views&page=all

Are you referring to part# 34 & 32 in the below image?

Capture.JPG

Edited by scr200

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3 minutes ago, scr200 said:

Are you referring to part# 34 & 32 in the below image?

Capture.JPG

Yes

From you pic it sure seems to be leaking from the apump cover, and loosing one of those orings would do it.

There is also a 'body' seal on the carb bowl that is the gasket for the cover, which also comes loose.

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19 minutes ago, Krannie McKranface said:

Yes

From you pic it sure seems to be leaking from the apump cover, and loosing one of those orings would do it.

There is also a 'body' seal on the carb bowl that is the gasket for the cover, which also comes loose.

Well look what I found on my garage floor. This looks to be the right size...Ill pull the carb tomorrow and see if it fits (if Im missing one).

On the off chance that does not fix the issue, what do you mean by a 'body' seal on the carb bowl? Are you referring to part#28? I know that is installed right now. 

58e5b11127bb0_IMG_42981.thumb.JPG.68f130ac861cb14bd667367374a6e4ac.JPG58e5b11a7fb08_IMG_42991.thumb.JPG.98cf89a0a89a803687786ee587f7fcf8.JPGCapture.JPG.9b6834b08bd6e4325de73fa192ed64f6.JPG

Edited by scr200

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I put that o-ring in the AP and it solved the leaking gas issues. However, the bike still immediately dies when i go WOT or when  I pull the choke out. 

Maybe I should put the 45 Pilot Jet back in as the 48 did not solve the hanging idle, cleaning the carb and replacing the seals did. 

The bike idles fantastic now, way better than it did prior to cleaning the carb and replacing the slide disk seal and fuel elbow seals. 

Is bog at WOT and dying when pulling the choke a lean or rich condition type issue? 

Edited by scr200

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5 hours ago, scr200 said:

I put that o-ring in the AP and it solved the leaking gas issues. However, the bike still immediately dies when i go WOT or when  I pull the choke out. 

Maybe I should put the 45 Pilot Jet back in as the 48 did not solve the hanging idle, cleaning the carb and replacing the seals did. 

The bike idles fantastic now, way better than it did prior to cleaning the carb and replacing the slide disk seal and fuel elbow seals. 

Is bog  at WOT and dying when pulling the choke a lean or rich condition type issue? 

Pilot has nothing to do with your issue, but yes you need a 45 pilot.

You probably re-assembled the apump system incorrectly.....or there is an actual problem there.

You need to verify the squit of the apump, by using a mirror (take the filter out) or by tilting up the subframe.

Billions of posts about apumps.   

 

Pulling the choke should kill the bike unless it's stone cold. Even then it's not a big deal.

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4 hours ago, Krannie McKranface said:

Pilot has nothing to do with your issue, but yes you need a 45 pilot.

You probably re-assembled the apump system incorrectly.....or there is an actual problem there.

You need to verify the squit of the apump, by using a mirror (take the filter out) or by tilting up the subframe.

Billions of posts about apumps.  

 

Pulling the choke should kill the bike unless it's stone cold. Even then it's not a big deal.

That link was very helpful, thanks. Ok performed the following:

-Verified float is correct at 8mm

-Cleaned float needle and seat and verified the needles rubber tip was in good shape

-Noticed I have the o-ring mod, but with safety wire, so went from a 55 to a 40 Leak Jet since that seems to be what people recommended for that mod (good idea or did I go too low?)

-Blew air through all jets

-Adjusted accelerator pump adjuster screw as per the manual

-Sprayed Carb Cleaner through the slanted inlet on the bottom of body to clear brass nozzle in intake bell

-Recorded Jets as: Main Jet: 180, Pilot Jet: 48, Leak Jet: 40, Starter Jet: 72, Pilot Air Jet: 105 & currently have Fuel Screw 2 turn out

........and success! Sort of. The brass AP nozzle is giving a strong 1 second stream, but hits the slide plate for a bit so I need to adjust the timing screw.

Now the bad part is that the bike wont start. I have not had any starting issues prior to the carb tinkering. Would changing the leak jet and/or pilot jet cause the starting issue?

 

Edited by scr200

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It won't start because it is most likely flooded.

With the ignition on, press the estart and the kill button at the same time, while holding the throttle wide open.....for about 8 seconds.

Now start it with no choke and no throttle.

Turn up you idle screw a full turn first so it will start, and when warm, lower it as low as it will go, then turn the fuel screw to find the highest idle.

Now readjust the idle with the idle screw if needed.

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15 minutes ago, Krannie McKranface said:

It won't start because it is most likely flooded.

With the ignition on, press the estart and the kill button at the same time, while holding the throttle wide open.....for about 8 seconds.

Now start it with no choke and no throttle.

Turn up you idle screw a full turn first so it will start, and when warm, lower it as low as it will go, then turn the fuel screw to find the highest idle.

Now readjust the idle with the idle screw if needed.

I wish it had e-start. LOL. What is the kickstart equivalent to that? Hold kill switch and throttle wide open while kicking? The rest I can do no problem. 

Edited by scr200

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8 minutes ago, scr200 said:

I wish it had e-start. LOL. What is the kickstart equivalent to that? Hold kill switch and throttle wide open while kicking? The rest I can do no problem. 

Yes

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12 minutes ago, Garage_Dog said:

Just curious... why hold the kill button?

Im assuming so the engine goes through its cycles without ignition thus draining gas from wherever caused the flooding. But thats just a guess. 

16 hours ago, Krannie McKranface said:

Yes

Bike is starting up and after some fuel screw and idle screw adjustments is running smoothly!! Infinite thanks for all your help!!! No bog, no hanging idle. WOOT! Just in time for the harescramble this weekend. The bike has never sounded this smooth before. Amazing what a good carb clean and proper setup does. 

Here comes the dreaded "that said".....I have a VERY slight "sputter" when accelerating or constant throttle. Not much, just enough to be annoying. Also there is a slight delay when coming completely off the throttle until engine braking/decel happens. Any ideas if it was due to the carb clean, assembly, or change in jetting? 

Also, I am going to clean air filter and swap plugs tomorrow. 

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25 minutes ago, scr200 said:

Im assuming so the engine goes through its cycles without ignition thus draining gas from wherever caused the flooding. But thats just a guess. 

Bike is starting up and after some fuel screw and idle screw adjustments is running smoothly!! Infinite thanks for all your help!!! No bog , no hanging idle. WOOT! Just in time for the harescramble this weekend. The bike has never sounded this smooth before. Amazing what a good carb clean and proper setup does. 

Here comes the dreaded "that said".....I have a VERY slight "sputter" when accelerating or constant throttle. Not much, just enough to be annoying. Also there is a slight delay when coming completely off the throttle until engine braking /decel happens. Any ideas if it was due to the carb clean, assembly, or change in jetting? 

Also, I am going to clean air filter and swap plugs tomorrow. 

Could be several things, but most likely it is a worn emulsion tube (needle jet), bad intake valve clearances, bad TPS setting, or, even an over-oiled airfilter...

I would change the needle jet the next time you have an hour to spare.

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46 minutes ago, Krannie McKranface said:

Could be several things, but most likely it is a worn emulsion tube (needle jet), bad intake valve clearances, bad TPS setting, or, even an over-oiled airfilter...

I would change the needle jet the next time you have an hour to spare.

I stumbled across this and describes my condition exactly: could this be all it is? I guess I cant test it by disconnecting the TPS to see if stutter goes away. 

 

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14 minutes ago, scr200 said:

I stumbled across this and describes my condition exactly: could this be all it is? I guess I cant test it by disconnecting the TPS to see if stutter goes away. 

 

The YZ line of ECU's is not known to have the same problem as the WR does. On the WR, from 2006-2011 they all have the partial throttle studder. 

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4 minutes ago, Krannie McKranface said:

The YZ line of ECU's is not known to have the same problem as the WR does. On the WR, from 2006-2011 they all have the partial throttle studder. 

Ah bummer. Ok, needle time it is. Would the slight stutter suggest just a worn needle that needs replaced or do I need to change it our for a different type and/or clip position? Ill do some searching too. Interesting that it only showed up after fixing the hanging idle and bog.....

The top end was just recently re-done so Im hoping its not the valves, but I can check those as well and shim as necessary after this weekends harescramble.

The TPS adjustment seems to be a bit difficult so hopefully the previous steps solve it first. 

 

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49 minutes ago, Krannie McKranface said:

Not the needle, the needle jet.................emulsion tube. It is supposed to wear, vs the needle wearing

Ohh, the "tube" screwed to the MainJet. Got it. Is that a once and is done type piece or can I clean it? I believe it had a "C32" etched on it, is that sound right or do I need to change up the type? 

You're gonna have to start billing me. LOL. 

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