Opinions Tapered D. Head Rods

[rbabos]

"always found that the front cylinder always has more wear on the minor thrust side of the cylinder than the rear cylinder does and it also runs the hottest because of the additional friction created."

I've always maintained the front cyl. runs hotter than the rear, but many here disagreed with me when I stated it a few years ago. Their thinking is it gets more air than the rear. Hotshots explanation of the rotation of the crankshaft when the piston is at BDC makes a lot of sense to me.

Also, that same rotation pulls oil to the rear..does it not?
Sorry for taking this a bit off "track"

I think it runs hotter if the cooling air was removed because it works harder to maintain a fixed rpm than the rear. Add load,  this is amplified. Cooler air hitting the front masks what's really going on with temps. I still claim it's from the uneven firing degrees between the front and rear placing more heat and wear on the fronts components. I believe the front is also prone to more oiling since back in the earlier days the front cyl case bores actually had block offs to reduce the amount of oil force up the front cyl from crank rotation.
Ron

[Hillside Motorcycle]

I was chatting with Reggie @ R&R and he mentioned the non- bushing rod change happened late 2006.

The one's we work on, are bushed...........
Scott

[Hot-Shot Motorworks]

I was chatting with Reggie @ R&R and he mentioned the non- bushing rod change happened late 2006.

The one's we work on, are bushed...........
Scott

Years back we used to have S&S make some special 7.440" rods with .927 pins and they were not bushed.  We had very good success with them.  We are now seeing those engines returning for rebuilds and with anywhere from 50,000 - 75,000 miles on them they look and feel like they did when we installed them.  If any rod was to fail on the small end these would have.  The application was in the early Evo 117" with 4 5/8" stroke X 4" bore using a short 7.440" rod and these things produced anywhaere from 160 -180 hp depending on what version you had.

[turboprop]

Harley made the change to bushing-less rods (small end) in late 2010.

[rbabos]

Harley made the change to bushing-less rods (small end) in late 2010.

That's what I remember as well. Same time parent metal pinion hole in cam plate. I don't have a problem with either one, myself.
Ron

[turboprop]

Have not heard of a single issue with the new bushing-less connecting rods. Maybe because they have only been out for a year and a half or so. I guess any issues will come out as the warranty runs out on these bikes and people start to hot rod them.

The bushing less/tapered rods should weigh a bunch less than a traditional square-end connecting rod. Would certainly make for a faster revving motor.

I wonder if these rods are able to be retrofitted to earlier cranks?

[Hot-Shot Motorworks]

Yes they can be installed on the early model T/C's.  Have many sets in stock if you need any.

[autoworker]

I saw the HD bulletin with rods minus the bushings.Now..who has seen one in a production bike?I have yet to hear of a firsthand experience or image of an actual production rod without the bushing.
Not doubting,but have yet to see or hear about one.

[turboprop]

Thanks for the offer Hot-Shot, at this point I am just thinking out loud. I will need a TC crank in the future but have not nailed down the specs. My buddy Dan Baisley thinks I should run 8" rods. Thinking right now is 4.250" bore by 4" stroke with 8" rods. The hard part is making this fit into an un-cut OEM FXR frame. Any insight?

[Jeffd]

I saw the HD bulletin with rods minus the bushings.Now..who has seen one in a production bike?I have yet to hear of a firsthand experience or image of an actual production rod without the bushing.
Not doubting,but have yet to see or hear about one.

I did see a photo of a slipped bushing in a 2011 bike. 

[Hot-Shot Motorworks]

Thanks for the offer Hot-Shot, at this point I am just thinking out loud. I will need a TC crank in the future but have not nailed down the specs. My buddy Dan Baisley thinks I should run 8" rods. Thinking right now is 4.250" bore by 4" stroke with 8" rods. The hard part is making this fit into an un-cut OEM FXR frame. Any insight?

There isn't much clearance on that frame and it might be difficult to accomplish.  Dan is very intelligent and he is correct in using an 8" rod which will greatly reduce the rod angle and make for a happier engine.  My calculation says that the cylinder height is going to raise .330 if you use a piston for a 4" stroke engine.  If you were to use a piston for a 4 3/8" stroke engine ( which has a smaller ring pack to allow a shorter compression height) this would increase the cylinder height only .1425".  You might be able to accomplish that without modifying the frame. 

[turboprop]

I'll apologize upfront to everyone else that is following this thread for going off subject here.

Dan is smart, maybe too smart sometimes. But his concerns of ring seal and chasing the tune are valid. We have looked at pistons with shorter compression heights. Also looking at other areas like rocker boxes. The Delkron website claims their rocker boxes save almost .500" compared to oem rocker boxes. I have a set of the Delkron boxes, .500" is an exaggeration, my side by side measurements show them as being .200" less than stock. Every little bit helps.  I wrestle with this every day, 8" rod all bore 114" vs a cookie cutter 124". The rod to stroke ratio of the 124 is horrible and the larger bore of the 114" allows for a larger valve and less shrouding, the 4" crank is readily available and will allow higher rpms while maintaining a reasonable piston speed. Decisions, decisions.

I am currently in possession of an S&S TC case for evo frames. This case has the S&S spread pattern, makes head selection a challenge. If I were to do an off the shelf 124", then S&S heads are available for less than $500 but flow like crap and would require an expensive 4.625" crank.

If I go the 114" route, Axtell could make a set of ductile cylinders with the S&S base pattern and the oem harley top pattern. This setup allows allot more choices for heads. A set of MVA or Hurricanes are less than $1,400. More decisions.

[Hot-Shot Motorworks]

Good Luck !!!!

[turboprop]

Like I said, I wrestle with this daily but will probably not spend a dime on it until the Taj-Mah-Motor is back in the bike. Then I will shift attention to the Smack-A-Hoe engine. Right now it is just an abstract.

[RG2007]

I have done several upgrades to late model bushing-less bikes, They look fine to me........

[Hillside Motorcycle]

2012 CVO 110" has bushings.
Scott

[BVHOG]

The first tapered rods I saw here were on an 06 cvo 103, even with my small hobby here I have seen a VERY egg shaped rear rod on an 08 Road Glide and a pair of slipped pin bushings on a 117 built over a stock welded crank. As for the non bushed rods it seems hit and miss, a friend pulled down a 2012 Saturday and it still has bushings, fuel moto has previously mentioned non bushed rods here. As for the rods themselves, my limit here other than the cvo bikes is a 107.
No way in hell am I taking the chance on those in a built 113-up.   
As for the Diesel comparison even with the relatively low rpm of the V-twin it is still a high rev motor compared to most diesels.
I have built a few diesel industrial motors and some had tapered rods some didn't. Keep in mind tapered rods would also increase the ability for oiling in comparison to the small oil hole at the top of full bushed rods.
As for opinion I think it was a really bad idea(tapered rods) in an area that was previously working just fine and I don't see benefits in this application only downsides.

[aharp]

Yep, i know the factory said 11 models are supposed to be bushing-less (which i am in favor of) but ive pulled apart several 12 models yet and had bushings in them 

[Admiral Akbar]

Non-bushed rods are not new.. I've yet to see any kind of bronze rod pin bushing on a Japanese bike..

As far as the fronts burning up the bushing, I seriously doubt that it's differences in the amount of work done buy the front cylinder. It is definitely not a difference in rod angularity between front and back cuz there ain't any difference. I'm  sure longer skirts and rod to stroke ratios help with thrust on the cylinders and ring seal fer sure.. I'd be more inclined to believe that the layout of the motor gives the front rod a bit less oil then an the back. Also explains why slipper skirts have more of a problem.. Harder target for the oilier to hit.. Also explains why reversing the rods helped..


Max

[glens]

Glens....It is difficult to describe without having illustrations of how the rod angles are in an engine.  The next time you have an opportunity to examine a disassembled engine watch the rod angles in relationship to each cylinder and you should be able to understand what I am saying.  The highest load on the front cylinder happens on the compression stroke and the highest load on the rear cylinder happens on the power stroke.  Hope this helps....

I certainly appreciate your taking the time with this for me. 

Based on what you've consistently said about this in the present thread, if one were to have at their disposal an actual (official) sectional side view "drawing" of the engine assembly, the bore centerlines would be seen to intersect below the center of the crank circle and/or the wrist pins would be located symmetrically offset away from the center of the vee.  Interesting...

I don't doubt for a moment that you're seeing the wear patterns you describe.  However my real-drawing-uninformed gut wants to say factors other than system geometry must be at play here; that it would be more of a dynamic phenomenon.

To the other aspect of this thread, I've isolated and attached pages 4 and 6 of  Harley's "2011_MY_Technical_Forum.pdf".

[attachment removed after 60 days by system]

[Don D]

Do you think "running change" may mean as stock depletes?

HotShot
You do crank work on the TC obviously. What do you do to upgrade the rods on a hard charger high compression late TC or do you?

[Jeffd]

Do you think "running change" may mean as stock depletes?

I bet that is correct but is strange that some 2011's have the bushings and some 10's don't.

[glens]

Maybe they found an old crate of them?

[Hot-Shot Motorworks]

HotShot
You do crank work on the TC obviously. What do you do to upgrade the rods on a hard charger high compression late TC or do you?

We install H-Beam Rods, in severe duty engines we turn the rods around for stability.  Reassemble, true & weld.  Pretty much a bullet proof crankshaft.  Check out the link below and this will give you more details on what we do to regular cranks.  If you have any questions, contact us.

http://www.hotshotmotorworks.com/didja_know.htm

[1FSTRK]

HotShot
You do crank work on the TC obviously. What do you do to upgrade the rods on a hard charger high compression late TC or do you?

We install H-Beam Rods, in severe duty engines we turn the rods around for stability.  Reassemble, true & weld.  Pretty much a bullet proof crankshaft.  Check out the link below and this will give you more details on what we do to regular cranks.  If you have any questions, contact us.

http://www.hotshotmotorworks.com/didja_know.htm

When you say turn the rods around does the front rod become the rear rod?
How/why is this an improvement over the original orientation