High compression pistons VS. stroker
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Tourer
Joined: Sep 2016
Posts: 375
Likes: 15
From: Illinois
Ok...so what do yall consider reasonable compression. I was thinking 10:1 was the high end of reasonable. I have saddle bags. Carrying a bottle of octane boost isnt a big deal.
if I add new pistons, I need to have the lower end rebalanced, right. I was going to do bearings anyway. Just asking.
if I add new pistons, I need to have the lower end rebalanced, right. I was going to do bearings anyway. Just asking.
Last edited by Bill wallace; Sep 16, 2018 at 06:57 AM.
Seasoned HDF Member
Joined: Jun 2015
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From: Canada
Unreasonable in my opinion.
Road Master
Joined: Apr 2012
Posts: 979
Likes: 38
From: new orleans,la
Ok...so what do yall consider reasonable compression. I was thinking 10:1 was the high end of reasonable. I have saddle bags. Carrying a bottle of octane boost isnt a big deal.
if I add new pistons, I need to have the lower end rebalanced, right. I was going to do bearings anyway. Just asking.
if I add new pistons, I need to have the lower end rebalanced, right. I was going to do bearings anyway. Just asking.
Seasoned HDF Member
Joined: Jan 2011
Posts: 157,524
Likes: 57,081
From: Michigan 15 Minutes East Of Hell
As said... no Substitute for Cubic Inches... especially when torque or Rideability is desired... now Horsepower... Horsepower is a Product of RPM [look at how it is measured] We call it "pops per quarter mile" certainly Not a product of longer stroke.. All of this assumes you know exactly what you intend to accomplish. Drag Racing??? short stroke/big bore spin it hard= Win!!! Fun to ride = Stroker... downside being more stroke equals more vibration, and harder on driveline parts [assuming you actually use it]. A simple compression increase... within reason [no spark knock] along with the correct cam... = good , cheap. Fun!! Downside=No Braggging.
Choose yer poison... only Jap Bike guys Brag about Horsepower!!!! For good reason!!!!
Choose yer poison... only Jap Bike guys Brag about Horsepower!!!! For good reason!!!!
Club Member
Joined: Mar 2009
Posts: 66,126
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From: Niles Canyon Ca.
Best thing I ever did for my 72 was poke her out to 88" went bigger 3-5/8" bore by 4-1/4" stroke with lighter flywheels @ 9 to 1 comp. Didn't make it into a street racer but the thing was a locomotive and could run 70mph all day long 2 up with gear and in the hills she'd out pull all the evo guys easy, got 60 to 75K between rebuilds on her. With some head work and a bigger cam it was a whole new animal again. Best part was it was direct bolt in no goofiness with stroker plates, longer cylinders and the related headaches fitting everything up to those bring like pipes & intakes, frame clearancing, ect..
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Joined: Nov 2006
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From: la la land jerzey
Best thing I ever did for my 72 was poke her out to 88" went bigger 3-5/8" bore by 4-1/4" stroke with lighter flywheels @ 9 to 1 comp. Didn't make it into a street racer but the thing was a locomotive and could run 70mph all day long 2 up with gear and in the hills she'd out pull all the evo guys easy, got 60 to 75K between rebuilds on her. With some head work and a bigger cam it was a whole new animal again. Best part was it was direct bolt in no goofiness with stroker plates, longer cylinders and the related headaches fitting everything up to those bring like pipes & intakes, frame clearancing, ect..
and engine mileage numbers come out the same stroker verses big bore but of course its who is driving the machine that makes it last -
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,608
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From: Cental, MI
Unless yer competing especially heads-up.. I don't recommend that Method... LOL
Best thing I ever did for my 72 was poke her out to 88" went bigger 3-5/8" bore by 4-1/4" stroke with lighter flywheels @ 9 to 1 comp. Didn't make it into a street racer but the thing was a locomotive and could run 70mph all day long 2 up with gear and in the hills she'd out pull all the evo guys easy, got 60 to 75K between rebuilds on her. With some head work and a bigger cam it was a whole new animal again. Best part was it was direct bolt in no goofiness with stroker plates, longer cylinders and the related headaches fitting everything up to those bring like pipes & intakes, frame clearancing, ect..
Anymore... If I want Performance.. I learned the Hard way... get an EVO... My shovels hang around 9: 1 [measured] compression, with a Mild Cam... even an H seems to like a bit of compression..Been riding around happily for many years this way. Since finally coming to the conclusion, aided by countless trips down Track, that EVO is Cheap, Easy, performance... and If ya can't afford that... About any Jap bike is cheapest.. biggest Performance.. I ride happily along on my "Antique".....
Even an old 1200 FLH with a number 1 cam, is unbelievably fun..
.
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Seasoned HDF Member
Joined: Jul 2014
Posts: 8,608
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From: Cental, MI
Ok...so what do y’all consider “reasonable” compression. I was thinking 10:1 was the high end of “reasonable.” I have saddle bags. Carrying a bottle of octane boost isn’t a big deal.
if I add new pistons, I need to have the lower end rebalanced, right. I was going to do bearings anyway. Just asking.
if I add new pistons, I need to have the lower end rebalanced, right. I was going to do bearings anyway. Just asking.
Bigger bore for sure tho... Nothing bad .. in fact, it was surprisingly smooth... always wished we could have torn that engine down just to see the resultant balance factor!!!!
