Pushrod Strength Choice

[Bagger]

I'm completing my 117" 2002 Road King build today. 
Just curious as to opinions.  Thinking of using SE Perfect Fit fixed length -0.030" pushrods versus Smith Brothers adjustable pushrods.  Which one would you think would most likely minimize pushrod flex, reduce valve-train harmonics, be stronger and more durable.  I'm not concerned with convenience of install and removal.

Smith Brothers ADH7125B
Adjust Pushrods 7/16" X 0.120" tapered to 3/8" 24 TPI
Weight:  Intake 154g / 5.4 oz.  Exhaust 155g / 5.5 oz
I adjusted and removed to measure.  Adjusted length Intake 10.377"  Exhaust 10.401"

SE Perfect fit -0.030"
Weight: Intake 90G / 3.15 oz. Exhaust 91g / 3.20 oz
Fixed length: Intake 10.369". Exhaust 10.485"


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[kd]

Two important considerations here.  What weight valve springs are being used and what is the rpm you want to control the valve train at.  The flex is determined by the work load and the rpm they are exposed to. IMO Weight concerns (as you've included) on the valve train are mostly very marginal under lower rpm and low spring weight stress. 

I will add that SB pushrods are built with flex abatement being their top consideration.  That said, you would need the engineering testing info on both to determine which is more appropriate to your stated major concern of flex.  Anecdotal answers will be all you will otherwise get.  Smith Brothers are very free with their information and will probably give you an honest detailed answer to this question.  I for one would like to hear the way they phrase their response if you do decide to call them.

FWIW, I removed my +.030 solids from my 120 crate when I built it up based on advice from one of the top head porter / engine builders in North America.  I explained I would use the rpm up to 6200 daily and he set the valve spring weight based on that.

[Bagger]

Two important considerations here.  What weight valve springs are being used and what is the rpm you want to control the valve train at.  The flex is determined by the work load and the rpm they are exposed to. IMO Weight concerns (as you've included) on the valve train are mostly very marginal under lower rpm and low spring weight stress. 

Valve springs are 185 lb.  Rpm range 2500 - 5000

[kd]

Two important considerations here.  What weight valve springs are being used and what is the rpm you want to control the valve train at.  The flex is determined by the work load and the rpm they are exposed to. IMO Weight concerns (as you've included) on the valve train are mostly very marginal under lower rpm and low spring weight stress. 

Valve springs are 185 lb.  Rpm range 2500 - 5000

You were responding as I was editing and adding info.  Good information though.  There are some highly qualified head gurus on the site that hopefully will give opinions that carry more weight than mine on the springs.  When My springs were selected I did as I was told. 

[Don D]

Very high level comment
Run the largest diameter that will package without hitting. There is less flex. Drill the top inner tubes at .625 one inch down from the top depth, best done by lathe and tail stock or tool post held drill. The tips on Smiths pushrods are a good design and stay seated on top. The weight is not a factor. The weakest link is the adjuster. Ignore the factions that are saying fixed length cots pushrods are more reliable when the adjustables are installed properly. That is a myth. With all the stack changes we make very few will actually be the right length unless a custom set is made.  No comment on the springs.

[kd]

FWIW Don, based on the rpm range alone my personal choice for something I was doing would be as you have said.

[Bagger]

Good info...  Sounds like preference is Smith Brothers adjustables...

[turboprop]

I'm completing my 117" 2002 Road King build today. 
Just curious as to opinions.  Thinking of using SE Perfect Fit fixed length -0.030" pushrods versus Smith Brothers adjustable pushrods.  Which one would you think would most likely minimize pushrod flex, reduce valve-train harmonics, be stronger and more durable.  I'm not concerned with convenience of install and removal.

Smith Brothers ADH7125B
Adjust Pushrods 7/16" X 0.120" tapered to 3/8" 24 TPI
Weight:  Intake 154g / 5.4 oz.  Exhaust 155g / 5.5 oz
I adjusted and removed to measure.  Adjusted length Intake 10.377"  Exhaust 10.401"

SE Perfect fit -0.030"
Weight: Intake 90G / 3.15 oz. Exhaust 91g / 3.20 oz
Fixed length: Intake 10.369". Exhaust 10.485"


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Another option is to build the engine with a set of adjustables. After the engine is broken in and you are satisfied with their adjustment, remove them without changing their length. Then send them to Smith Bros and have them make you a set of tapered fixed length rods. Also, the term fixed length is not really accurate as the Smith Bros solid pushrods are adjustable (with shims).

The real discussion is will your combination benefit from solid pushrods. The arm chair crowd here will debate and hypothesis and give advise without actually doing anything. When in doubt, call Baisley, Zippers or Scott Palmer.

IME, the TC 124 in my red bike has an intake larger than 2.1", exhaust larger than 1.7" and regularly sees >6,500 rpm. I broke it in using adjustables and transitioned to solids about a year later. The break-in tune made 153hp, a year later with a lot of miles, it cranked 160hp on the same dyno during the same month. Only real change was solid pushrods, a small jetting change and some small changes to the timing table. That being said, these solids are a pain in the butt. If you are of the arm chair crowd and constantly worried tappets and stuff, solids are not for you.

[JW113]

And the fact that it had run in miles on it, so less internal friction and maybe better ring seal than a fresh build.

-JW

[kd]

Another option is to build the engine with a set of adjustables. After the engine is broken in and you are satisfied with their adjustment, remove them without changing their length. Then send them to Smith Bros and have them make you a set of tapered fixed length rods. Also, the term fixed length is not really accurate as the Smith Bros solid pushrods are adjustable (with shims).

The real discussion is will your combination benefit from solid pushrods. The arm chair crowd here will debate and hypothesis and give advise without actually doing anything. When in doubt, call Baisley, Zippers or Scott Palmer.

IME, the TC 124 in my red bike has an intake larger than 2.1", exhaust larger than 1.7" and regularly sees >6,500 rpm. I broke it in using adjustables and transitioned to solids about a year later. The break-in tune made 153hp, a year later with a lot of miles, it cranked 160hp on the same dyno during the same month. Only real change was solid pushrods, a small jetting change and some small changes to the timing table. That being said, these solids are a pain in the butt. If you are of the arm chair crowd and constantly worried tappets and stuff, solids are not for you.

    It was Dan Baisley that did my MVA heads and gave me the advice I mentioned. 

[Thermodyne]

The biggest reason for running non adjustable rods is cost.  And on a twin cam there is very little if any time penalty as far as installing them. 

The tapered ones give you a little more clearance at the head, but that can also be accomplished by opening the hole up.

Don't agree with the above comment about weight not being a factor.  Every gram you can take out of the valve train is of value.  Its just that because of that fat overweight rocker, there just isn't any power to be gained from lighter pushrods. With that said, for a street run Harley there is no reason to favor fixed rods over adjustable rods because of weight.

Past that, for what perfect fit rods cost from SE, you can buy custom pushrods.  A set of Manton's 5/16 .118 wall chromoly rods will set you back about $60.  A set of 11/16 to 5/16 tapered .120 wall chromoly rods will run you about $104

[Bagger]

 

[itsafatboy]

I have the smith brothers , nice rods, would like to see them get the billet covers they have designed done so you have more clearance , i use sumax covers but they dont sell any longer,  they have more clearance and these rods have fat bottom adjusters ,  the other thing to think about is if you want to change cams or lifters you dont need to remove tank and rocker stuff thats a big deal to me.  SB also has .145 wall adjustables if you want more but they will require rocker removal. not sure why they went with bigger threads on these, and if you notice they are the same ones fueling sells,       

[Ohio HD]

S&S, Colony, SE parts all have proper pushrod tubes and clips to allow more room for the Twin Cam to adjust pushrods. Probably other brands as well.   

[kd]

I have the smith brothers , nice rods, would like to see them get the billet covers they have designed done so you have more clearance , i use sumax covers but they dont sell any longer,  they have more clearance and these rods have fat bottom adjusters ,  the other thing to think about is if you want to change cams or lifters you dont need to remove tank and rocker stuff thats a big deal to me.  SB also has .145 wall adjustables if you want more but they will require rocker removal. not sure why they went with bigger threads on these, and if you notice they are the same ones fueling sells,       

SB makes pushrods and they are rebranded for and sold by several other companies.

[60Gunner]

Currently running  s&s quickies but I'm all for custom made solids. SBs was out of the thickness I wanted. I'll  get bored some day, measure and change.

[hrdtail78]

Valve springs are 185 lb.  Rpm range 2500 - 5000

IMO, you will not see a loss or gain of anything with either one you choose.

[JSD]

EVO covers work for adjustables on TC. I run Crane Adj strong & light