Your Thoughts on Upgrades and Engine Life (?)
#32
11-23-2014, 07:13 AM
Although there's always a "cost" in wear and longevity on a hot rodded motor, it's negligible if it's done right and not beat to death every day.
The longer the stroke the faster the pistons are moving in the bores and that will cause a little bit of extra wear and tear on that area of the motor.
Larger displacement engines will tend to generate more heat and that is never a good thing.
In my opinion, having built hundreds of motors over the years, 88" to 95" is the optimum size for these big twin motors, headwork and cams can work wonders for performance and I know from personal experience that in most cases a small displacement motor can leave a big inch motor in the dust if it's set up properly.
The longer the stroke the faster the pistons are moving in the bores and that will cause a little bit of extra wear and tear on that area of the motor.
Larger displacement engines will tend to generate more heat and that is never a good thing.
In my opinion, having built hundreds of motors over the years, 88" to 95" is the optimum size for these big twin motors, headwork and cams can work wonders for performance and I know from personal experience that in most cases a small displacement motor can leave a big inch motor in the dust if it's set up properly.
The shorter the stroke the faster the pistons are moving
#33
11-23-2014, 07:42 AM
Ultimate HDF Member
Wrong....
At, let's say 2500 RPM on a short stroke motor the pistons have less distance to travel in the bores and are therefore moving slower.
We're not talking about RPM to road speed here, there are too many gear ratio variables to accurately relate piston speed to road speed.
RPM for RPM though...Long stroke pistons must move faster in the bores to get the job done.
Last edited by Greezey Rider; 11-23-2014 at 07:46 AM.
#34
11-23-2014, 11:17 AM
Not even remotely true. It is exactly the opposite. If you have a 3" stroke, the piston is traveling 6" per engine revolution. At six thousand rpm, 6" time six thousand equals 3,000 feet of piston travel in one minute. 4" stroke, the piston is traveling 8" per engine revolution. At six thousand rpm, 8" time six thousand equals 4,000 feet of piston travel in one minute. If you're traveling farther in the same time frame, physics dictate you're traveling faster in order for that to happen.
#35
11-23-2014, 03:11 PM
Club Member
As far as piston speed is concerned you all need to study engine geometry a bit more closely. Think about it. Plainly a piston is stationary when briefly at tdc and bdc, then accelerates to max velocity at mid-stroke, before slowing down again. The critical aspect of a fast running engine is peak piston speed. Hence a Jap bike with short stroke and egg-cups for pistons can safely run at stratospheric rpm, while a Harley with long stroke and ice-buckets for pistons cannot begin to compete, at least on rpms.
Last edited by grbrown; 11-23-2014 at 03:13 PM. Reason: Expanded.
#36
11-23-2014, 07:05 PM
#38
11-24-2014, 04:23 PM
Having been on this forum for a few years, I've read my share of stories that span the spectrum.
I've read about guys that have completely rebuilt their bikes with excellent results and others that frig up a simple spark plug change.
Some plan the their mods with care and are rewarded with fine-running machines whereas others haphazardly throw parts together then soon experience some bazaar performance issues whining like little girls the entire time.
And some riders take the time to learn their machines and how to care for them. Others proudly claim they "ride like they stole it..." and then scratch their butts trying to fix "unexpected" problems.
I have seen no scientific studies but rely on my own experience and wisdom. I've ridden for many years, crossed the US more than a couple times, and have enjoyed thousands of trouble-free touring miles. I no longer ride with guys that carry hundreds of dollars worth of tools and parts. And I certainly won't ride with guys that spend thousands of dollars on paint, chrome, and other fancy do-dads.
Remember, these are just machines made by humans. Over time, materials, technology, and skills change.
Yes, I modify my bikes but all those mods trend towards the touring I do. I carry a tire pressure gauge and that's about it.
I've read about guys that have completely rebuilt their bikes with excellent results and others that frig up a simple spark plug change.
Some plan the their mods with care and are rewarded with fine-running machines whereas others haphazardly throw parts together then soon experience some bazaar performance issues whining like little girls the entire time.
And some riders take the time to learn their machines and how to care for them. Others proudly claim they "ride like they stole it..." and then scratch their butts trying to fix "unexpected" problems.
I have seen no scientific studies but rely on my own experience and wisdom. I've ridden for many years, crossed the US more than a couple times, and have enjoyed thousands of trouble-free touring miles. I no longer ride with guys that carry hundreds of dollars worth of tools and parts. And I certainly won't ride with guys that spend thousands of dollars on paint, chrome, and other fancy do-dads.
Remember, these are just machines made by humans. Over time, materials, technology, and skills change.
Yes, I modify my bikes but all those mods trend towards the touring I do. I carry a tire pressure gauge and that's about it.
Just curious, what's wrong with carrying some tools with you on the road for that repair that can get you going? I carry a small variety of tools that I think I might need and more importantly the guys I ride might need being that some of them have no bags to store stuff....... not trying to be a dick here, just wondering that's all, I'm sure you your reasons........ one being someone wants you to do something to their bike when your out riding........Maybe? lol
#39
11-24-2014, 04:31 PM
Club Member
Just curious, what's wrong with carrying some tools with you on the road for that repair that can get you going? I carry a small variety of tools that I think I might need and more importantly the guys I ride might need being that some of them have no bags to store stuff....... not trying to be a dick here, just wondering that's all, I'm sure you your reasons........ one being someone wants you to do something to their bike when your out riding........Maybe? lol
#40
11-24-2014, 04:41 PM
Cruiser
My '99 is bored to 95" with ported heads, forged flattops, .030" head gaskets, Wood TW6HG cams advanced 4° and a bored throttle body with red injectors and high pressure regulator. It makes 98/102 with the current tune. I did the mods at 37,000 miles and it now has just shy of 156,000.
The bottom end has never been apart and shows no signs of needing to come apart any time soon. I am not nice to it.
The bottom end has never been apart and shows no signs of needing to come apart any time soon. I am not nice to it.
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