 big bore, stroker?
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what is the differance between a standard big bore kit and a stroker big bore kit? Excuse my ignorance but the term "stroker" has confused me for sometime now (speaking of engines of course!)
Nick Derry
"Whoever dies with the most toys, wins"!
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Re: big bore, stroker?
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Joined: Feb 2007
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Fe Butt
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Fe Butt
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the distance the piston travels is longer on a stroker.Crank work needed and different connecting rods.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: big bore, stroker?
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Loquacious
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Loquacious
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we should do this every weekend!
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Re: big bore, stroker?
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So does the case have to be split and remove the crank? What gives a stroker longer travel? Shorter pistons? Modified connecting rods? What is the performance differance? Why is the sky blue? Did my hamster really go to heaven?
Last edited by B00ZEfighter; 01/01/2008 10:27 PM.
Nick Derry
"Whoever dies with the most toys, wins"!
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Re: big bore, stroker?
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Loquacious
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Loquacious
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yes the case has to be split. it is a lot of work. if i was going to split the cases i would just go with the 1100 big bore and be done with it. keep your stock crank and still make 80Ibs of TQ. but i think most will be just as happy with the 904, and it is considerably cheaper
Frank
(Former)05 BA tbike pipes, ai removed, Freak, mikuni hsr 42's, 904, ported/polished head, 1mm oversized valves
NOW-2010 silver and black tbird
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Re: big bore, stroker?
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Quote:
What gives a stroker longer travel?
The crank is modified, the big end bearings (where the rods connect/mount onto the crank) are offset welded and ground to basically push the distance from the center of the crank to the center of the con rod big end bearing out farther. It gives the piston more up/down distance to travel, increases the speed the piston travels, and also increases the leverage the piston's force (combustion) while at the same time increasing displacement (engine size).
In short, a stroker is an engine with a crank modified to increase the size and power of the engine.
Expensive, but very effective.
There is no greater thrill than being shot at with no consequence. -Churchill
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Re: big bore, stroker?
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Check Pants
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Quote:
Why is the sky blue? Did my hamster really go to heaven?
WHY IS THE SKY BLUE?
The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.
However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.
As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.
The circle of life and death
We collected some garden tools and decided on the best spot for the burial to take place. It was as we were digging, thankfully in frost-free soil, that he asked me completely out of the blue, and without any awkwardness, “Do animals go to heaven?†We carried on with the task in hand as our conversation took many twists and turns. After we had buried Fudge we placed a piece of wood where there would have been a headstone had it been a human being, and then had a hot drink (he made it for me). I don’t know how it came up, but we started talking about the food chain of plants and animals. I asked whether the chain might be better considered as a circle, since every species depended in some way on all the others.
So we were not far off his original question. Now it so happens that I have been thinking quite a lot recently about the theology of creation and eschatology, and had been surprised how much reference there is in the Judaeo-Christian scriptures to the whole earth and all the things that live on it. (Traditional interpretations have tended to be rather anthropocentric.) I said that it was inconceivable to me that there could be anything that I could think of as heaven (we readily agreed that no one knew what heaven would be like), without animals, birds, bugs and the rest. It would be incomplete. And I couldn’t imagine heaven as incomplete or partial. In fact, if animals were missing there would be a sense of loss and separation. It would be as if life on earth had not been taken seriously enough. You can see that his question had really got me thinking!
SOLD: 07 Black BA, 39mm FCRs, TPUSA stage 1 head, TPUSA 813 cams, TPUSA 10.8:1 pistons, TTP #3 igniter, Specialty Spares Long Cannons, Tsukayu Hard Bags. 82HP/55tq
NEW: 19 Goldwing Tour DCT
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Re: big bore, stroker?
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Nick Derry
"Whoever dies with the most toys, wins"!
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Re: big bore, stroker?
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Oil Expert
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This shows a cross section of a (very simplified) standard crank, and the way they weld & grind it to increase it's stroke distance (and therefore the engine's overall capacity). 
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Re: big bore, stroker?
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Learned Hand
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Learned Hand
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Are you sure the welded area and ground area are the not the other way round 
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Re: big bore, stroker?
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Fe Butt
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Fe Butt
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No thats right you weld up the side away from the crank pin and grind away the other side, but in actuality the whole pin gets ground all the way around. Whats being done is the crank pin is being moved farther away from the center of the mains. I haven't been inside one of these engines yet but from what I am seeing I am guessing it isn't actually a crank pin in this engine but a one piece crankshaft. I mean the big end journal when I say crank pin.so at TDC the piston is higher in the cyl. and lower at BDC making it a longer stroke hence "stroker"
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: big bore, stroker?
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Yep, The_Dog's got it right. If you reversed the ground & welded areas you'd move the big end of the conrod closer to the crank's centre of rotation and shorten the stroke.
Of course the crank I showed is a very simplified one and the design is taken from a typical car's crank so in reality it'd probably look somewhat different but the theory's still the same. You also need to take things like the piston's rise into account, and find custom pistons where the gudgeon pin is set higher into the piston body so crown doesn't run into the valves etc.
Another way to have the same effect is to use conrods with a smaller diameter big-end journal. This allows you to simply re-grind the journal on the crank with a different centre, without the need to weld. This used to be preferred method on the old 1960's & 1970's Mini's, which originally came with a "large journal crank" but later came out with a "small journal crank". The real trick these days is to find one of the early "large" cranks that's been unmolested and is in good condition. Very useful as they're a cast iron crank and very difficult to weld.
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Re: big bore, stroker?
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Learned Hand
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Learned Hand
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Got it now,I was thinking it was the holes the pin located in that where ground and welded, you all mean the pin/big end. 
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Re: big bore, stroker?
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Check Pants
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Check Pants
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cant a "stroker" also be made by using longer con rods or by relocating (not literally...I mean by purchasing new pistons) the actual position of the piston on the con rod?
Or has my thinking all these years been way off base? (this is a good possiblity)
SOLD: 07 Black BA, 39mm FCRs, TPUSA stage 1 head, TPUSA 813 cams, TPUSA 10.8:1 pistons, TTP #3 igniter, Specialty Spares Long Cannons, Tsukayu Hard Bags. 82HP/55tq
NEW: 19 Goldwing Tour DCT
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Re: big bore, stroker?
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Learned Hand
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Longer rods will definitely give you more lift in the stroke.
It will also give you less on the bottom of the stroke.
Wrist pin positioning effectively does the same thing.
Only way to "stroke" a cylinder is to change the crank journal position.
Tony G
'03 America
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Re: big bore, stroker?
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Check Pants
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yeah..I guess thinking about it if it was done as I described it would only increase compression and not effect the downstroke.
SOLD: 07 Black BA, 39mm FCRs, TPUSA stage 1 head, TPUSA 813 cams, TPUSA 10.8:1 pistons, TTP #3 igniter, Specialty Spares Long Cannons, Tsukayu Hard Bags. 82HP/55tq
NEW: 19 Goldwing Tour DCT
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Re: big bore, stroker?
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Joined: Feb 2007
Posts: 23,200 Likes: 58
Fe Butt
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Fe Butt
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Well no it would effect the down stroke, but it wouldn't effect the total distance traveled.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: big bore, stroker?
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Joined: Mar 2007
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Check Pants
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Check Pants
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thats what I said 
SOLD: 07 Black BA, 39mm FCRs, TPUSA stage 1 head, TPUSA 813 cams, TPUSA 10.8:1 pistons, TTP #3 igniter, Specialty Spares Long Cannons, Tsukayu Hard Bags. 82HP/55tq
NEW: 19 Goldwing Tour DCT
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