exhaust port to wide

south central hoon · Post by **south central hoon** » July 23rd, 2010, 3:02 pm

thanks! hmm...wouldn't you expect to see blowby?

glen howell · Post by **glen howell** » July 23rd, 2010, 7:35 pm

wiseco,pro-x vertex the big 3

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glen howell · Post by **glen howell** » July 23rd, 2010, 7:39 pm

wiseco to pro-x

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glen howell · Post by **glen howell** » July 23rd, 2010, 7:43 pm

wiseco to vertex

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glen howell · Post by **glen howell** » July 23rd, 2010, 7:45 pm

vertex to pro-x

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http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » July 23rd, 2010, 7:59 pm

glen, the area beside the wrist pin is the trouble, i left my blackbook at the shop, but the vertex is wider at the cutout than the pro-x(which is narrower than stock!) wiseco had made a piston that was narrow, the old 554 and some early 636 versions that had fore-aft cuts, but later made the wide exhaust that almost went to the pinhole before they went full round.

The prox issue is that there is a clear window from the reed area, beside the pin, and out the corners of even a stock exhaust port, some worse than others.

glen howell · Post by **glen howell** » July 23rd, 2010, 8:07 pm

???? ask the engineers, even ask honda?? Eric Gore wrote a book about it ??? I still use them all thats why a flow bench is so important !!!Glen

glen howell · Post by **glen howell** » July 23rd, 2010, 8:28 pm

wiesco,vertex,pro-x

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glen howell · Post by **glen howell** » July 23rd, 2010, 8:30 pm

the late 554 and some 636

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glen howell · Post by **glen howell** » July 23rd, 2010, 8:33 pm

a 97mm honda piston for a cr-500 cylinder with special sleeve work,made by VENOLLA

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bearorso · Post by **bearorso** » July 24th, 2010, 1:17 am

glen howell wrote:wiesco,vertex,pro-x

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Is the Wiseco pictured there the new 871?

And does the Vertex come with the ex bridge holes as std?

glen howell · Post by **glen howell** » July 24th, 2010, 10:35 am

That Vertex came that way I have never gotten one drilled before.

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » July 24th, 2010, 10:57 am

somebody will have returned that vertex, its not how they come factory

The wiseco pistons have changed from wiseco ALOT thru the years.
the old 554 was 371g - had large cut intake side and pin relief fore+aft
late 554 was 360g - had small cut intake side and pin relief fore+aft
early 636 was 374g - had large cut intake side and pin relief fore+aft (554 casting # on bottom)
mid 636 was 374g - had small cut intake side and pin relief towards intake
last 636 was 431g - had small cut intake side and full round

and now they have another that sounds to be like the early 636 with the large cut intake and pin relief fore+aft

I have a box full of these old wisecos, every different one i think, gotta look back at things every once in a while

glen howell · Post by **glen howell** » July 24th, 2010, 11:02 am

Bob, See what I mean now that's pure know how ,He didn't have to go to 10 different forms to come up with the right info. ROOSTY you have my vote. Glen

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » July 24th, 2010, 11:23 am

i dont think i have that 554 listed that you have pictured

f'n wiseco flip floppin #s and specs

100hp honda · Post by **100hp honda** » July 24th, 2010, 12:04 pm

this is forged mahle 92.25mm. you can see how they went about making it light without having short circuit issues.

92.25 almost 1oz lighter than wiseco which is 3.25mm smaller

89mm wiseco boat anchor version

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » July 24th, 2010, 1:07 pm

thats from a ktoom? same pin as honda? whats the pin height like in comparison?

i'm guessing you needed the spacer on the deck because you used a long cr rod in it, why not a short cr rod?

100hp honda · Post by **100hp honda** » July 24th, 2010, 5:36 pm

ya 20mm pins on both. honda is about 8mm down lower. never checked into the short rod so i dont know.

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » July 24th, 2010, 8:22 pm

why the heck arent we using that piston?

100hp honda · Post by **100hp honda** » July 24th, 2010, 9:43 pm

i got no desire to do anything like that. maybe it would work if someone has free time to mess with it

long rod in short cases then shave the jug down alittle more ? hell i dont know

BannedCR500Riders.com

exhaust port to wide