Author Topic: Air leak with clutch pulled in  (Read 2309 times)

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ajd187

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Air leak with clutch pulled in
« on: September 12, 2016, 12:15:12 pm »
Yesterday riding the MB I noticed that I had an lean surge with the clutch pulled in.  Once the bike was in gear, and running it, it was fine.   Same for an idle when cold.

It has been harder to start cold lately too.

I read that this can be an alternator (left side) crank seal.  Sound right?  And if so, of these parts, which one is the one I need?  #70?

« Last Edit: September 12, 2016, 12:17:11 pm by ajd187 »
2007 KTM 200 XC-W #59

Brenden

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Re: Air leak with clutch pulled in
« Reply #1 on: September 12, 2016, 04:27:35 pm »
Part #70 is the crank seal for that side.  i would check the pipe seal, carb boot, reed gasket, make sure the pilot jet isnt clogged, adjust air screw, etc. before attacking the crank seal.  You are very likely going to have to split the cases to change that.  did you put new seals in when you did the crank a couple years ago?  cranks seals dont commonly go bad.

Is it a surge or a high idle?

mirageags

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Re: Air leak with clutch pulled in
« Reply #2 on: September 12, 2016, 05:42:37 pm »
I changed my right side seal last summer without cracking cases :D
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ajd187

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Re: Air leak with clutch pulled in
« Reply #3 on: September 13, 2016, 09:10:49 am »
Part #70 is the crank seal for that side.  i would check the pipe seal, carb boot, reed gasket, make sure the pilot jet isnt clogged, adjust air screw, etc. before attacking the crank seal.  You are very likely going to have to split the cases to change that.  did you put new seals in when you did the crank a couple years ago?  cranks seals dont commonly go bad.

Is it a surge or a high idle?

I'll check all those too.  I might even have some of those gaskets and stuff on hand since I ended up with two gasket kits when i rebuilt everything a few years ago. 

I was googling the problem and that's where I got the idea that it might be the left side seal.  Saw a post on Thumpertalk that said that condition was that seal.   

It seemed to only do it when the clutch was pulled in and it was rolling.  It's also been harder to start cold.  Once it's hot it's fine. 

Kind of like a high idle, but I said surge. 

I did change the plug and the air filter before the MB so I will check those too.
2007 KTM 200 XC-W #59

mirageags

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Re: Air leak with clutch pulled in
« Reply #4 on: September 13, 2016, 10:14:20 am »
Did a little digging this morning and i think it's an air leak in your air boot or carb or something like that. You did the bottom end not too many hours ago i find it odd the left crank seal would be bad already
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ajd187

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Re: Air leak with clutch pulled in
« Reply #5 on: September 13, 2016, 02:41:51 pm »
yeah the bottom end is...maybe 50-55 hours old.  maybe less.

I'll clean it and check for leaks and go from there. A carb boot would make sense.  as far as I know the airbox is all original and could be dry rotted by now jsut from age.
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bardeenm1

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Re: Air leak with clutch pulled in
« Reply #6 on: September 13, 2016, 03:49:15 pm »
It can't hurt to replace your reeds while you are pulling things apart if you have never replaced them.

ajd187

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Re: Air leak with clutch pulled in
« Reply #7 on: September 20, 2016, 09:38:04 am »
I finally had more time mess around with this this weekend, and again this morning.

Pulled the flywheel cover.  Clean as a whistle back on that side.  MASSIVE flywheel, by the way.  No wonder these bikes rev so slowly!

the idle is definitely hanging.  so that's the issue. 
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Trail Ryder

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Re: Air leak with clutch pulled in
« Reply #8 on: September 20, 2016, 12:08:19 pm »

the idle is definitely hanging.  so that's the issue.

Any cracks in your intake manifold?  How do your reeds look?
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Brenden

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Re: Air leak with clutch pulled in
« Reply #9 on: September 20, 2016, 04:18:35 pm »
bad reeds tend to make the bike run real rich.

If you want to get to the bottom of it with the least screwing around, first check your pilot jet.  Make sure it isnt plugged.  I would just put in a new one.  The holes are so small it as very hard to tell if they are plugged.  If that doesnt do anything, then you have an air leak in the engine.  You can either spray some water around the gasket surfaces and listen for it to bog alittle, or get some plugs and put 10psi or so into the engine and check it with soapy water.

I think it is more likely that the carb is dirty.  It is far more common to have a fuel issue than for an engine to develop an air leak.  Especially an engine that has low hours on it.

ajd187

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Re: Air leak with clutch pulled in
« Reply #10 on: September 20, 2016, 04:24:15 pm »
I have a pile of pilot jets so I'm going to switch that out too.  Like you said that is the fastest and easiest thing to check.  I did put Seafoam in the gas tank today too to clean it out.  But just changing the jet is easy enough. 

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mirageags

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Re: Air leak with clutch pulled in
« Reply #11 on: September 20, 2016, 05:40:07 pm »
When my bike ran rich, especially with clogged pilot, the idle never hung with clutch in, it would try to just die out. Run it with the seafoam for 15 minutes and see what happens.
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ajd187

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Re: Air leak with clutch pulled in
« Reply #12 on: September 21, 2016, 12:07:30 pm »
Yeah I thought it was just clutch in, but the idle hangs all the time.

I did seafoam it, it's been sitting in the carb for a day.  Gonna try it tomorrow most likely and see if it's any better.   Then swithc the pilot.
2007 KTM 200 XC-W #59

bardeenm1

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Re: Air leak with clutch pulled in
« Reply #13 on: September 21, 2016, 03:08:26 pm »
Does the idle drop after you blip the gas? This would be a sign of a lean condition.  If the idle stays up and continues to climb then it is probably an air leak.
When the idle climbs pull the choke does the idle drop?

ajd187

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Re: Air leak with clutch pulled in
« Reply #14 on: September 22, 2016, 08:34:06 pm »
Seemes it was just a dirty carb.

I put seafoam in the tank on Tuesday and ran it a bit.  Then I let it sit until tonight.

Fired right up. Idle does not hang.

I usually drain the carb if it is going to sit. I either forgot or there is build up from running ethanol crap in it. I'm gisssing it is that.
2007 KTM 200 XC-W #59