intake seals
Thread Starter
|
Road Captain
Joined: Jan 2010
Posts: 658
Likes: 52
From: Lakeshore Wis.
intake seals
having a hard time keeping the seals in the intake where it meets the intake port on the head. Replaced them twice now. Within about 900 miles. It started completely stock, and with the aluminum intake too. It starts to back fire the instant I touch the start button. At first, just the first time that day. Then a little more often. Then, more and more! New gaskets, godd for a couple weeks, and it starts all over again! 2018 107. Clean surfaces, lightly lubed. All positioned before tightening. Also changed the injectors and o rings on the too. WTF ?! Anyone else have this happen ?
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,116
Likes: 7,638
From: Poolville
Trending Topics
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,925
Likes: 8,027
From: poway
I guess everyone missed that he was using a aluminum manifold on a 18 107.. They were plastic.
One thing to look at is the air cleaner bracket.. If you went aftermarket AC, I'd check the spacing on the air cleaner bracket. You may want to check general fit. Assemble the manifold into the rings without the seals on the head. Is there a little bit of float on the manifoldd If that is OK Assemble with the rubber seals and get the manifold as straight as possible. If not OK, you may need to trim some off the manifold. Check the fit between the AC bracket and the head. There need to be a spacer that fits perfect and the holes need to line up perfect. When you tighten the AC bolts, you need to make sure its not placing any load on the throttle body / manifold..
One thing to look at is the air cleaner bracket.. If you went aftermarket AC, I'd check the spacing on the air cleaner bracket. You may want to check general fit. Assemble the manifold into the rings without the seals on the head. Is there a little bit of float on the manifoldd If that is OK Assemble with the rubber seals and get the manifold as straight as possible. If not OK, you may need to trim some off the manifold. Check the fit between the AC bracket and the head. There need to be a spacer that fits perfect and the holes need to line up perfect. When you tighten the AC bolts, you need to make sure its not placing any load on the throttle body / manifold..
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Road Warrior
Joined: May 2011
Posts: 1,956
Likes: 439
From: florida
As max says, the AC back plate should be lined up before before snugging down the manifold. I’ll add, the manifold bolts need to be incrementally torqued down alternating between front/ rear, top/ bottom bolts while watching alignment.
Thread Starter
|
Road Captain
Joined: Jan 2010
Posts: 658
Likes: 52
From: Lakeshore Wis.
So just to reiterate part of the beginning, this issue started when the bike was factory stock, with the plastic manifold in place. Changing to the aluminum didn't change anything. Thanks to ALL that are posting. There are some very good ideas here. I pretty much "torque sequence" everything I put together. I'm a machine builder by trade. But, you still learn something everyday from people who've been there !
I will be checking the manifold without the seals next time I take it off. I think I checked the port alignment when I installed it, but will check that again as well.
So,.... Here's what's interesting now. Normally when I start the bike with fuel injection, I turn on the switch, wait for the pump to stop, then hit the button. No real reason, just the way I have done it since my 1st F.I. bike in 1996. What I started doing is, turn on the switch and hit the starter right away. In 30 to 50 starts, it has only popped once, and that was very mild,(comparatively).
Hmmm. I already changed the injectors and the O-rings twice, just because, so that's not it. But, is it possible there could be an issue with the ECM giving it too much of a shot @ startup ? Or maybe a ground or connector that is affecting that? Not positive, but I think it is the front cylinder where the issue is.
I will be checking the manifold without the seals next time I take it off. I think I checked the port alignment when I installed it, but will check that again as well.
So,.... Here's what's interesting now. Normally when I start the bike with fuel injection, I turn on the switch, wait for the pump to stop, then hit the button. No real reason, just the way I have done it since my 1st F.I. bike in 1996. What I started doing is, turn on the switch and hit the starter right away. In 30 to 50 starts, it has only popped once, and that was very mild,(comparatively).
Hmmm. I already changed the injectors and the O-rings twice, just because, so that's not it. But, is it possible there could be an issue with the ECM giving it too much of a shot @ startup ? Or maybe a ground or connector that is affecting that? Not positive, but I think it is the front cylinder where the issue is.