I posted earlier this year about a problem with my 06 Road King Custom. I bought the bike in Sept last year from a dealership and wasnt offered a warranty because of too many modifications by the previous owner. 4 3/8 SE flywheels 103 big bore kit, woods gear driven cams and SE HTCC CNC ported heads. After 43000 miles on the build I bought the bike and and it developed issues namely a collapsed lifter because of material in the pump and filter. The dealership agreed to rebuild waving the labor charges and discounting the parts. We couldnt find replacement HTCC pistons so went with a 3 7/8 flat top with new stroker flywheels, new cylinders, same heads and new SE 251 cams, billet cam plate and hydraulic tensioners. Running D&D Boarzillas 2 into1 exhaust with 52mm throttle body. Picked it up Sunday and it runs and sounds great the only complaint I have is a whistle throught the throttle body at low idle. It sounds like its pulling a ton of air with each intake stroke. Not sure where to go from here like I said it runs great but I cant get used to the low idle whistle. Im sure it has something to do with the cams and the flat tops and HTCC heads.

 

normal, some seem to make more noise than others depending on the build and the way they draw air through the intake. put some ear plugs in and run it!

 

I was hoping for some suggestions to eliminate the whistle. I understand the ports and valves in the HTCC heads are bigger but there has to be a better setup without spending an arm and a leg. I was thinking different cams the dino looks good, starts to level out at 90+ rpm at 3000rpm up to 6000 rpm topping at 98. I'm not looking for the fastest bike in town just want it strong on the road. I wanted to keep the heads but I guess the lack of HTCC pistons is the heart of the problem.

 

Don't know squat about this whistle thing (sorry), but those numbers seem very low for such a build and 103ci is borderline-to-way-too-small for a Boarzilla. What is your CCP? If below 190psi, consider milling the heads/decking the cylinders/reducing headgasket thickness to get it between 190-195psi (9.2 to 9.5:1 corrected CR) and trade the Boarzilla for a Fatcat.

 

Which air cleaner do you have on the bike?

 

Sounds more like a vacuum leak some where. I would start spraying water around the intake and throttle body seals and go from there..

 

You would be better off spraying it with WD40

 

It does sound like perhaps a gasket leak somewhere.....?
Scott

 

A whistle sound at low rpm could be coming from the head breathers

 

Sprayed around head gasket and manifold with carb cleaner, no leaks. Running Stage 1 air filter, and I'm told the pressure is well above 100. What I really neded to start with was another set of the HTCC pistons. It sounds great and runs strong I just hate hearing it at a stop light.