Engine Knock on Start up

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Nov 18, 2013 | 02:57 PM

#11

gipper

Road Master

Joined: Jul 2010

Posts: 1,042

Likes: 86

From: Centeral Coast, California

Before you go chasing a phantom problem that doesn't really exist, ask some questions from people in the know on your cams about reversion. It's something I recently learned about that showed up in my bike after installing the Woods TW-222.

Reversion is caused by the overlap in your cams, which is essentially (as best I understand it) exhaust gasses that are popping (so to speak) right behind your throttle body. It's harmless, and is too be expected when installing a more aggressive set of cams than your stock cams.

I was bothered by the same sound in my bike, and have been told by many on this website, and by Fuel Moto, that it's to be expected and is not problematic. I almost don't notice mine anymore, and like yours it goes away when there's more velocity to push the gasses down the header.

Ask the dealer that you bought the cams from if reversion should be expected from them.

Nov 19, 2013 | 08:16 PM

#12

garbear

Intermediate

Joined: Apr 2011

Posts: 34

Likes: 0

From: near Milwaukee

Quote:

Originally Posted by jimvac49

Thanks for all the advice. Looks like I need to change the lifters.
I had one other thought. Could be carbon knock? I sprayed water into the throttle body several months ago, but it didn't seem to do anything.
Thanks again.

Never really heard of the carbon knock thing?? I heard water will steam and "clean" the piston top like a car with a bad head gasket. Beware it may wind up in the bottom end as well.

I put Jims lifters in 2 bikes now with adjustable pushrods and it was money well spent, way quieter. Tons of brands out there, will you do it yourself?

Nov 19, 2013 | 10:31 PM

#13

TUCCI

Extreme HDF Member

Joined: Jun 2011

Posts: 10,216

Likes: 224

From: Glendale AZ

Quote:

Originally Posted by DTTJGlide

If it sounds like an exhaust leak it's most likely a lifter, if you put in adjustable pushrods when you changed cams it's an easy fix. I'd replace them all, not with HD lifters, S&S, Comp Cams, or Gatermans are some of the best.

I have a similar problem and ended up changing all the lifter and push rods at 3 full turns lash. Still does it, I didn't figure it would help but I needed to be sure the mexico made lifters weren't an issue.
I'm going to go back to dino oil on my next rotation, don't expect much of a difference but the oil is thinner than the dino equivalent not to mention I change it at 3k miles. I know, I know I just started an oil thread