Definitive Wiseco Piston Thread

http://www.youtube.com/user/500bigbore · December 21st, 2010, 12:29 pm

OK, I've have all these versions in my archives except the new coated one.
its funny how Honda needed 2 different piston designs thru the entire lifespan of the cr500 and wiseco needs all these.

http://www.youtube.com/user/500bigbore · December 21st, 2010, 1:17 pm

kball1313 · Post by **kball1313** » December 21st, 2010, 2:26 pm

Gets actual work done, 5,000 bbm messages, 300 phone calls a day, and still manages to crank out these files!

Tharrell · Post by **Tharrell** » December 21st, 2010, 3:58 pm

That's just youth.
They should bottle and sell that shit!

2T500 · Post by **2T500** » December 22nd, 2010, 2:16 am

I add to the honda service manual (and for my engine builder) these awesome technical doc's you post Roostius and they are so helpful - big thanks to you and Millar Race Engines

Who balance's my crank for each weight variation in piston - these slugs are heavy with big variations ! the machine to balance the crank is really expensive and the Mallory metal to do it for cranks like cr500, shouldn't the piston weight factor in this?

right now I am running an oversize (90mm) weisco in my 87 motor with nothing special done to the crank other than a rebuild, should we be sending crank & piston to be balanced when fitting a different (or any non stock weight) piston or is the piston weight less of an issue ? somehow i think it is

http://www.youtube.com/user/500bigbore · December 22nd, 2010, 5:05 am

I've done alot of custom work to the pistons for guys too. We've lightened the full round version to 370 grams or so, i'll make a post for it today.
As far as crank balance work, I have the Hines Liberator balancer, i can physically do them, but i'm not up for taking hoons $ for it. Its too hit and miss trying to interprate how and where in the rpms you prefer to ride it.

2strokeforever · Post by **2strokeforever** » December 22nd, 2010, 5:27 am

but i'm not up for taking hoons $ for it

free?

j/k

http://www.youtube.com/user/500bigbore · December 22nd, 2010, 5:41 am

It was 358 grams after we lightened it

dubious01 · Post by **dubious01** » December 22nd, 2010, 9:28 am

kball1313 · Post by **kball1313** » December 22nd, 2010, 10:13 am

I was thinking about this and I need to get a tach hooked up on the motard and see what rpm window it cruises at most before the twirp swap happens. That way I can send a fresh wiseco crank i've got in at the same time.

dubious01 · Post by **dubious01** » December 25th, 2010, 11:22 pm

just bought a brand new vapor for $89 off ebay!
Nice unit, has coolant temp, and a bunch of other nice features.
Cool little unit, and cheap.

100hp honda · Post by **100hp honda** » December 26th, 2010, 12:01 am

hard to say why the shuffling. figure they should of had it sorted out 10+ years ago.

BrianPaul69 · Post by **BrianPaul69** » January 23rd, 2011, 10:13 am

100hp honda wrote:hard to say why the shuffling. figure they should of had it sorted out 10+ years ago.

Most of the changes are due to R&D, feedback from race teams and some engineer thinking he has a new idea to make the piston lighter, stronger and better performing in some way. The last variation with the coating is a good idea and also has a ring design change. I would be curious to know what actual performance differences / gains if any there are from the first Wiseco through to the last.

100hp honda · Post by **100hp honda** » January 23rd, 2011, 6:13 pm

it shouldnt take 10 years and 6 different designs to figure it out.
that tells me they didnt put much effort into it

.
the boat anchor really has me confused, why even sell that big heavy piece of crap.
fully assembled your looking at damn
near 500 grams banging around in the bore
and jack hammering on the rod and bearings.
dont take a engineer to see thats a bad idea

BrianPaul69 · Post by **BrianPaul69** » January 23rd, 2011, 6:21 pm

Whats the weight of the stock cast piston? That's the weight the crank should be balanced at from the factory and that should be the weight of any new piston (give or take a few grams) that is hung on the rod.

Regardless of bore size, brand or material used the pistons should stay within a few grams of each other. I mean who expects your average schmoe to tear out his engine, split the cases and have the crank re-balanced every time they do a rebuild? Not very practical in my book.

I'm also not sure how much material can be safely removed from a Wiseco piston to get it close to the same weight as a stock cast piston so it doesn't throw the balance way off.

blownbillybob · Post by **blownbillybob** » January 28th, 2011, 12:39 pm

Just got a wiesco in from eBay for $131.00 shipped 90.00 mm over ,weighed 527 piston-pin total my two stock piston-pins weighed 488,490 so I took some material off,got it down to 497 cut the out side by the wrist pin, made it look like the other 636# piston, I'll see how it feels this weekend I know with the stock piston that was in there no off idle vibes at all, when I first replaced the piston with 554# years ago I noticed wright away off idle vibes!!!!!

100hp honda · Post by **100hp honda** » January 28th, 2011, 4:26 pm

527g is bullshit. 92.25 with pin is 479g

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » January 28th, 2011, 4:45 pm

We get the bare piston to 350

100hp honda · Post by **100hp honda** » January 28th, 2011, 5:08 pm

350g is good. lowest i could safely get was 413g bare on 92mm bore. could probly skim 15g more but it aint worth the risk of what might happen

81cr450 · Post by **81cr450** » September 5th, 2011, 8:49 pm

That 636 was just pure lazyness, thinking they could cut out a step & no one would notice or care. Good to see they brought back the side reliefs & added coating. It "#636" could be used on some Vampire port setup though to cover any short circuit but... Thanks for the post Roostius

dannygraves · Post by **dannygraves** » September 6th, 2011, 1:06 pm

On my old gen-3 I built it with the piston it came with and just re-ringed it since it was very low hour. It had I believe the 3rd piston from the left and rode like a dream. I was having some major tuning issues and started to suspect a compression issue so I decided to just have it bored and dropped in the boat anchor and the bike vibed so bad after putting in that piston that it would physically hurt my feet to stand on the pegs at certain rpms. with the lighter piston the bike barely vibrated at all. After all the the issue ended up being the ignition coil

K-Man · Post by **K-Man** » October 6th, 2011, 5:53 pm

What part of the piston do you machine out to lighten it and can you always use your stock/previous piston as a benchmark?

johnnytheswede · Post by **johnnytheswede** » November 7th, 2011, 5:20 am

I weighted the standard piston at 89,25mm and i got 428 grams. The new Wiseco 871 at 89,50 mm was 420 grams. But the pin was a little heavier on the Wiseco, 60 grams, and the standard 40 grams, so 8 grams in difference.

Johnny

BannedCR500Riders.com

Definitive Wiseco Piston Thread

Definitive Wiseco Piston Thread

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