intake leak?? FXDX
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Intermediate
Joined: Sep 2010
Posts: 36
Likes: 1
From: Ohio
intake leak?? FXDX
Hey guys I have a question about checking for an intake leak. Bike is a 88ci 1999 FXDX Super Glide Sport. First two years of riding the bike after jetting for the stage one it ran perfect. Last year it started running lean, cold pop through carb and I could just feel it in the throttle like it was starving for fuel. If I pull the choke out a tad while riding it will take off. So I took the carb off and cleaned it out and no change. Did it again and still no change. This year I was told to put some propane to the intake gaskets and check for a leak. No change while idling. Shot both gaskets with starting fluid and bike stalled instantly which tells me theres a leak. Went to Harley and got new gaskets and installed them. Hit with the staring fluid again and stalled instantly. Got new gaskets and did it again. This time I took my time trying to make sure everything was perfect. I was told to spray it with WD-40 to check for leaks. I did and no change in idle. Hit them with the starting fluid and it stalled right out again! I am making sure I'm just hitting the gaskets in a short blast not to get in the carb or anything to throw it off. Bike is still feeling a tad bit lean but I don't have the carb pop anymore. In my opinion it is still leaking if it stalls when I hit it with the starting fluid. And it is instant. I spray the intake to cylinder gasket short and quick and it stalls instantly. And why aren't the others changing the idle speed? I was expecting idle to go up and not stall bike with the starting fluid. Any other ways to check for a leak before I tear it down a third time this week??? Any opinions on using starting fluid?? Thanks.
Road Captain
Joined: Jan 2012
Posts: 710
Likes: 2
From: San Bruno
when i was looking for intake leaks on my 80 ironhead, wd-40 worked great. sprayed around the intake and idle changed. cant say ive ever heard of starter fluid being used. try the wd-40 again but spray a little more than you previously did and if you have the straw get it right down to the gasket and spray all around if you can. if you end up taking it apart again check the manifold to see if its deformed or anything. also check the heads where it meets the manifold and see if anything there is deformed.
have you pulled the plugs and see what they look like? the plugs can tell you quite a bit about how your bikes running. if your not sure how to read the plugs post pics and someone will tell you.
have you pulled the plugs and see what they look like? the plugs can tell you quite a bit about how your bikes running. if your not sure how to read the plugs post pics and someone will tell you.
Seasoned HDF Member
Joined: Jul 2008
Posts: 9,281
Likes: 1,139
From: southeast PA
The only thing I use to check intake leaks is carb cleaner or throttle body cleaner. Never knew of anyone using starting fluid, but I may be wrong.
Mike's idea to check the manifold flanges for warping is a good one. Use a piece of glass to see if it lays flat.
Mike's idea to check the manifold flanges for warping is a good one. Use a piece of glass to see if it lays flat.
Outstanding HDF Member
Joined: Nov 2007
Posts: 2,289
Likes: 22
From: Beautiful Downtown Burbank
Have you checked the rubber seal between the carb and manifold for leaks?
I've found that a drop or two of motor oil smeared on the manifold gaskets makes it easier to center the manifold without leaks, and doing the same to the carb seal will help there too.
I've found that a drop or two of motor oil smeared on the manifold gaskets makes it easier to center the manifold without leaks, and doing the same to the carb seal will help there too.
Thread Starter
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Intermediate
Joined: Sep 2010
Posts: 36
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From: Ohio
Haven't tried the carb cleaner. Everything looked, good and clean but didn't do any mechanical checks, just visual. Doesn't look like it was ever been messed with or apart before. It has 32,000 on it. Man I don't want to pull this thing apart again!
Road Captain
Joined: Jan 2012
Posts: 710
Likes: 2
From: San Bruno
try the carb cleaner and see what happens. if idle changes pull it apart and check for warping in the manifold/heads. KK6pg also made a good point. check the seal between the carb and manifold. could also be leaking there too.
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Road Warrior
Joined: Apr 2010
Posts: 1,739
Likes: 10
From: Suffolk, England
Could be there is a warp in the manifold or slight head misalignment and you can't get a tight fit with stock gaskets. James make two oversizes of gaskets, the thicker blue ones will fix just about any leaks but at the risk of squishing out slightly inside the manifold.
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Advanced
Joined: Sep 2011
Posts: 95
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From: australia
hi,
when i replaced the rubber ring seal's on my inlet manifold, i lightly greased them inside and on the outside. no leak's.
also make sure you take your time alternately doing up the the allen bolt's.
it took me two attempt's, i think i failed the first time, because i failed to lubricate both side's of the rubber ring seal's.
i feel for you mate, sometime's the simply thing's can be a total pita.
good luck, grumpy.
when i replaced the rubber ring seal's on my inlet manifold, i lightly greased them inside and on the outside. no leak's.
also make sure you take your time alternately doing up the the allen bolt's.
it took me two attempt's, i think i failed the first time, because i failed to lubricate both side's of the rubber ring seal's.
i feel for you mate, sometime's the simply thing's can be a total pita.
good luck, grumpy.
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Intermediate
Joined: Sep 2010
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From: Ohio
The first set I tried to put on were the James blue seals. Just liked how the James seals went over the ends of the intake. I did oil the carb gasket because carb slides in it so tight. But I didn't oil or grease the intake gaskets. Thought about it but it didn't say anything in the factory manual to do it so I didn't. The second time I installed them I did take my time and made sure everything was centered and did take the allen bolts in slowley alittle at a time all the way around to try to keep things even. But I also did it dry. I'm gonna check for leaks again this morning with carb cleaner and then see what happens. I will also check around carb with it.