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Valve train noise
Old 02-08-2009, 04:59 PM
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Default Valve train noise

Mike Im a little concerned about the valve train noise, with the tw7h woods cam. I have an 07 road glide its a 103. Ported and polished heads 83cc and he took 2cc off the flat to pistons, I guess to raise the compression a little more. He put in the 55 HP inc. TB shes dynod at 107.22hp 109.29 TQ. My question is will the set up be ok without roller rockers. Hearing that valve train noise screaming at 3000 gets a little scary. Doc wasent able to tune the bike I had it done here in Miami. Mike also do you think the 55 TB was an over kill, Iv herd somtimes bigger isent always better. Thanks alot, Jeff
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Old 02-09-2009, 08:49 PM
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I to have valve train noise with my 103 build and I used the kit that the MoCo put together, the stage 3 with the 251 cams. I did not substitute any of the parts, I thought the noise might be due to the heavier valve springs that came with the kit. Your thoughts on this Mike would be appreciated. Thanks
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Old 02-10-2009, 10:49 AM
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Mike Mike is offline
Join Date: May 2005
Location: Oregon
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Both posts can be addressed here.

Valve train noise can be notoriously difficult to identify and/or correct. Having said that, things to check are rocker cover clearance around the valve spring retainers, push rod rub at the top of the covers, valve/piston clearance when using oversized valves and/or thin head gaskets, valve spring to guide seal clearance when using high lift cams, cam lobe to case clearance with high lift cams and 04E cases, tappet to case clearance with high lift cams and rocker to valve collar clearance (rare). Of course, these are all things that should be checked during assembly. Since neither of these are gear drive cams, we'll skip that discussion.

Another noise source can be the valve springs themselves. Dual coil valve spring sets can have a harmonic or surge that can manifest as valve train noise, typically around 2800-3200 rpms. This is often impossible to elemenate because it is a function of the spring design and its applicataion. This has NOT been known to cause failures but is chalked up to a price we pay for the performance. Our LMR-002 oil bypass spring was designed to help address these issues.

Roller rockers were mentioned as a possible solution. We've not seen rollers help and in fact may increase the noise.

For Jeff, the HPI 55 is not a bad choice and I would have recommended the 57 with ported heads. The good news is that on EFI bikes, size is less of an issue and it's better to be too big rather than too small (people are still thinking carburetors, see Kuryakins' note on this). Curious about the "2cc off the flat tops". Was this done for clearancing? It would seem this would lower compression, but I may not be understanding just what was done.
Mike Stegmann
Performance Consultant
Team Latus Motors Harley-Davidson

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