Need input, possible intake leak
Thread Starter
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5th Gear
Joined: May 2016
Posts: 9
Likes: 0
From: Stanardsville, VA
Need input, possible intake leak
So i think i have an intake leak, but I'm not positive. Bike won't run without enrichener pulled out and the carb farts a little.
It all started after I swapped the heads out. My Sportster is an 01, with 07 heads. During the long slow process of swapping them, my carb got gunked up. I cleaned it and did a rebuild. I also installed an inline fuel filter until I can get a new tank, mine got a bit rusty while it was apart. I got the bike all back together, with new gaskets of course, and the correct flanges for the late model heads. The reason I think it is the intake, is because I could not tighten the flange bolts with the carb on the bike, very limited space. So they were tightened with the carb off. I'm sure it could be other things causing this, which is why I'm looking for some input before I try to get it right. Eventually it will stop raining in VA and I want to ride.
It all started after I swapped the heads out. My Sportster is an 01, with 07 heads. During the long slow process of swapping them, my carb got gunked up. I cleaned it and did a rebuild. I also installed an inline fuel filter until I can get a new tank, mine got a bit rusty while it was apart. I got the bike all back together, with new gaskets of course, and the correct flanges for the late model heads. The reason I think it is the intake, is because I could not tighten the flange bolts with the carb on the bike, very limited space. So they were tightened with the carb off. I'm sure it could be other things causing this, which is why I'm looking for some input before I try to get it right. Eventually it will stop raining in VA and I want to ride.
did u have the filter before all of this happened?
try removing it if so .. and retest
check for leaks
spray some carb cleaner or starter fluid around the area if the motor revs higher you have a leak
try removing it if so .. and retest
check for leaks
spray some carb cleaner or starter fluid around the area if the motor revs higher you have a leak
Thread Starter
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5th Gear
Joined: May 2016
Posts: 9
Likes: 0
From: Stanardsville, VA
I'll try the carb cleaner tomorrow after work.
I didn't have the filter before, I noticed the orange gas and then put it on. I'll do that depending on what I find with spraying carb cleaner on it. Thanks to you both!
I didn't have the filter before, I noticed the orange gas and then put it on. I'll do that depending on what I find with spraying carb cleaner on it. Thanks to you both!
Road Captain
Joined: Mar 2009
Posts: 654
Likes: 734
07+ (EFI) heads have their manifold mating surfaces milled down .062" each, as compared to 91-06 heads which are made for a carb. That means a standard carb type manifold is 1/8" too narrow, and the gap to each head is greater.
As a result, it can be difficult to get a good seal right there. Lots of guys who've tried to use EFI heads with a carb manifold have had issues with the intake seals getting sucked into the ports when the throttle is chopped from high rpm.
Wider manifolds are available in the aftermarket for precisely this situation.
In terms of the installation, first off, use hex head bolts, not the allen head original bolts your bike came with. Then you can do it with a wrench, and there will be enough room. The placement and spacing of the bolts on 07+ heads makes this possible on both sides, where it's only possible on the spark plug side with carb type heads.
Second, leave the manifold flange bolts a little bit loose until the carb and air cleaner (or whatever is supporting the carb) are on. If the carb is going to block access to the pushrod side bolts, go ahead and tighten those, but leave the spark plug side bolts a bit loose. The idea is to let the manifold move and align as the carb is forced into it's final position by the air cleaner mounting. Then tighten the manifold flange bolts.
But if the manifold is not wide enough for the EFI heads, you may still have an issue.
As a result, it can be difficult to get a good seal right there. Lots of guys who've tried to use EFI heads with a carb manifold have had issues with the intake seals getting sucked into the ports when the throttle is chopped from high rpm.
Wider manifolds are available in the aftermarket for precisely this situation.
In terms of the installation, first off, use hex head bolts, not the allen head original bolts your bike came with. Then you can do it with a wrench, and there will be enough room. The placement and spacing of the bolts on 07+ heads makes this possible on both sides, where it's only possible on the spark plug side with carb type heads.
Second, leave the manifold flange bolts a little bit loose until the carb and air cleaner (or whatever is supporting the carb) are on. If the carb is going to block access to the pushrod side bolts, go ahead and tighten those, but leave the spark plug side bolts a bit loose. The idea is to let the manifold move and align as the carb is forced into it's final position by the air cleaner mounting. Then tighten the manifold flange bolts.
But if the manifold is not wide enough for the EFI heads, you may still have an issue.
Thread Starter
|
5th Gear
Joined: May 2016
Posts: 9
Likes: 0
From: Stanardsville, VA
Def intake leak, checked it with carb cleaner just now. Thanks for the input. And thank you aswracing for that great info. In case I have trouble finding it, do you know where I could get one of those intakes?
Thread Starter
|
5th Gear
Joined: May 2016
Posts: 9
Likes: 0
From: Stanardsville, VA
I think I can get an s&s manifold and a cv adapter, from what I have read anyway. Then sand the manifold down a little if needed.
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Thread Starter
|
5th Gear
Joined: May 2016
Posts: 9
Likes: 0
From: Stanardsville, VA
07+ (EFI) heads have their manifold mating surfaces milled down .062" each, as compared to 91-06 heads which are made for a carb. That means a standard carb type manifold is 1/8" too narrow, and the gap to each head is greater.
As a result, it can be difficult to get a good seal right there. Lots of guys who've tried to use EFI heads with a carb manifold have had issues with the intake seals getting sucked into the ports when the throttle is chopped from high rpm.
Wider manifolds are available in the aftermarket for precisely this situation.
In terms of the installation, first off, use hex head bolts, not the allen head original bolts your bike came with. Then you can do it with a wrench, and there will be enough room. The placement and spacing of the bolts on 07+ heads makes this possible on both sides, where it's only possible on the spark plug side with carb type heads.
Second, leave the manifold flange bolts a little bit loose until the carb and air cleaner (or whatever is supporting the carb) are on. If the carb is going to block access to the pushrod side bolts, go ahead and tighten those, but leave the spark plug side bolts a bit loose. The idea is to let the manifold move and align as the carb is forced into it's final position by the air cleaner mounting. Then tighten the manifold flange bolts.
But if the manifold is not wide enough for the EFI heads, you may still have an issue.
As a result, it can be difficult to get a good seal right there. Lots of guys who've tried to use EFI heads with a carb manifold have had issues with the intake seals getting sucked into the ports when the throttle is chopped from high rpm.
Wider manifolds are available in the aftermarket for precisely this situation.
In terms of the installation, first off, use hex head bolts, not the allen head original bolts your bike came with. Then you can do it with a wrench, and there will be enough room. The placement and spacing of the bolts on 07+ heads makes this possible on both sides, where it's only possible on the spark plug side with carb type heads.
Second, leave the manifold flange bolts a little bit loose until the carb and air cleaner (or whatever is supporting the carb) are on. If the carb is going to block access to the pushrod side bolts, go ahead and tighten those, but leave the spark plug side bolts a bit loose. The idea is to let the manifold move and align as the carb is forced into it's final position by the air cleaner mounting. Then tighten the manifold flange bolts.
But if the manifold is not wide enough for the EFI heads, you may still have an issue.
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