When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ignition/Tuner/ECM/Fuel InjectionNeed advice on ignition issues? Questions about a tuner? Have questions about a EFI calibration or Fuel Injection? Tips on Engine Diagnostics, how to get codes, and what they mean. Find your answers here.
I'm leaning towards another intake leak. I've fixed 2. Cracked o-ring on the front cylinder injector. New intake seals. HPI has a seal/ o-ring rebuild kit for 55mm throttle bodies. I'll start there. Thank you for your time and responses. 👊
Pull the throttle body / manifold and check how the manifold rings line up with the intake ports. In 06 the port configuration changed along with the manifold rings. IIRC the SnS motor uses the early rings. If the rings are wrong, the connection will leak.
Yep, if the bike is a 2006 and S&S uses the early (offset bolt pattern) intake mounting the flanges for the 2006 (symetrical bolt pattern) it will, for sure, cause an intake leak.
Simply spray some WD40, carb cleaner, or brake cleaner onto the flanges at the heads while the engine is idling. If the rpms change, up or down, you have an intake leak caused by the incompatible bolt patterns.
Note: Pay particular attention NOT to get the overspray into the intake (a/f or throttle body) which will cause the rpms to change producing a misdiagnosis.
Let us know what you find,
Bob
PS - If you have the original ECM you may want to plug it in and see how the idle behaves...just for diagnosis purposes.u
I think I'll forever be battling this issue. So I ordered a 58mm throttle hog from S&S. Sorry thundermax, guess you were just doing your job. Thanks all
So did you verify the bolt pattern from flange to head is correct?
Based on the picture showing the sealing oring it appears to me it was not sitting correctly as if the bolt patterns were not compatible.
Also the rubber seals are torn which usually indicates some movement after flanges were tightened...usually to get air cleaner backing plate to mount up?
Bob
I believe that's the case. This throttle body and intake were originally on a "built" 80ci motor with millennium jugs. My mechanic used everything he could when we put the S&S motor on. Checked with S&S about throttle body size, but didn't verify intake fitment. I'm thinking this has been the cause of my thundermax issues since buying the bike. The last seals were torn as well and I noticed quite a bit of movement when I removed the air cleaner backing plate. The bolts were tight and there was at least an 1/8 - 1/4" of movement. Are you suggesting dry fitting with air cleaner backing plate before tightening down the flanges?
Take a flange off the TB. Put it up against an intake port on the head. With the bolt holes lined up is the port in the middle of the flange?
If the flange bolt holes line up with the head bolt holes AND the port hole in the flange is in the middle of the port you are golden. If not you need to install the correct flanges for the heads you have.
Bob
I believe that's the case. This throttle body and intake were originally on a "built" 80ci motor with millennium jugs. My mechanic used everything he could when we put the S&S motor on. Checked with S&S about throttle body size, but didn't verify intake fitment. I'm thinking this has been the cause of my thundermax issues since buying the bike. The last seals were torn as well and I noticed quite a bit of movement when I removed the air cleaner backing plate. The bolts were tight and there was at least an 1/8 - 1/4" of movement. Are you suggesting dry fitting with air cleaner backing plate before tightening down the flanges?
So it came off an EFI sportster? Spacing may be off.
Flanges are wrong. Just found a side note on S&S site that informs of the need to purchase the off set flanges for '06 models. My mechanic ordered me a new 58mm throttle body from S&S on Friday. All I needed was the correct flanges. Ugh. 6 years of issues.
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.
Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.
