Roller Rockers
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Road Master
Joined: Feb 2014
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From: TN
Well I guess I am going to ask a question or two for my knowledge. What is correcting valve train geometry? I've seen it mentioned several times especially for high lift cams. And second, running a lift of .625 to .650 how much does that shorten the life of the valve train.
Thanks
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HDF Community Team
Joined: Jun 2006
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From: san antonio
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Joined: May 2008
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From: Ashland Ohio
If one goes down a few notches in cam lift, one other thing I would do is get rid of the springs in the 120r. These are double springs with near 500 lbs over the nose. IMHO, that is WAY overkill for a street ridden 120r. AV&V makes some nice beehives that fit right in and can handle the 660 lift fine and doesn't beat up everything to death.
Yes, the 120r came with the exact same stuff as does the current 103, including the **** ***** for lifters. Same lifters, same rocker shafts, same everything but the pushrods. The 120r has base gaskets on the bottoms of the cylinders and not o-rings, so MOCO supplies these engines with +30 pushrods. That means the pushrods are .030" longer. I took those pushrods and put in a 95 build for a buddy. He didn't want adjustables, and I like having pushrods around .140 into the hole, instead of 100. So, on that bike... I was 130 in the hole and it was nice and quiet. Whn I swapped my lifters out, I went with Smith quickies for the pushrods.
You REALLY cannot compare what goes on in a car with the bike you have, because the BIG thing is you are not driving the car while riding on top of the engine. Pushrod engines can and will make valvetrain noises. Some engines are better that others.
My big thing is the springs are too much for a street bike and the lifters the 120r comes with are pure junk.
Yes, the 120r came with the exact same stuff as does the current 103, including the **** ***** for lifters. Same lifters, same rocker shafts, same everything but the pushrods. The 120r has base gaskets on the bottoms of the cylinders and not o-rings, so MOCO supplies these engines with +30 pushrods. That means the pushrods are .030" longer. I took those pushrods and put in a 95 build for a buddy. He didn't want adjustables, and I like having pushrods around .140 into the hole, instead of 100. So, on that bike... I was 130 in the hole and it was nice and quiet. Whn I swapped my lifters out, I went with Smith quickies for the pushrods.
You REALLY cannot compare what goes on in a car with the bike you have, because the BIG thing is you are not driving the car while riding on top of the engine. Pushrod engines can and will make valvetrain noises. Some engines are better that others.
My big thing is the springs are too much for a street bike and the lifters the 120r comes with are pure junk.
Last edited by wurk_truk; Jun 18, 2014 at 09:21 PM.
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Joined: Sep 2013
Posts: 22
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From: Riverview Florida
wurk thanks for the response to my questions. You and Steve from GMR are on the same page with respect to the springs and lifters. Although he mentioned a different set of springs, and cutting the seats to have the right stem heights, and geometry, .010 over pistons bringing it to 11:1, lifters, and keeping the 266e cams bringing it to around 140 HP. It would considerably increase reliability, and quiet it down considerably. The biggest part of the noise is the stiff springs from what I`m being told.
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