BannedCR500Riders.com

I'm shopping around for wisecos and was wondering what the difference was between the pistons for '85-'89 and '90+. I am usign an '86 cylinder and at 89.5 mm bore. I noticed that they make the '90+ in and 89.75mm which would be awesome, but I don't know if it will work right or if the opening is different or what?
Thanks
Danny

No difference whatsoever as far as I know.

I seem to recall someone saying that the intake opening was different, but I'm wondering if its small and something a small grinder could easily fix

isn't the rod length shorter on the 85-88 models? If so the piston difference is probably in the piston pin height compared to the long rod models. This is the way it was with the TRX 250r quads.

na, because the pin height is the same, and the '87+ were the long rod and its the same piston through '89.
I'm starting to think it has something to do with the different head gasket.

The newer pistons will work in the all 480s & 500s

cool, but what exactly is the difference?

Danny Check your pm's

pstoffers wrote:Danny Check your pm's

What you gotta hide the differences??? Tell us man!

Ok, here is the skinny as I see it. They are same in every way except: 1) the 90's one has a slightl narrower inlet hole on the intake side, height is the same. 2) the 90's one is cast from a differant type of aluminum, it is much more white in color, the 80's one is much more silver in color.

So besides the aluminum issue of which I have no idea which is better. the only issue is on the 90's piston it would seem you got a upgrade to deal with the cracking issue by better support on the two fingers of the intake side.

dannygraves wrote:I noticed that they make the '90+ in and 89.75mm which would be awesome!
Thanks
Danny

Thats whats in mine and was glad to see that.

The one on the right is 85-89 left one is 90+

DUDE that piston is a trip man! Who chopped it up like that?

The rist pin caught a port and whala....

britincali wrote:DUDE that piston is a trip man! Who chopped it up like that?

Its an ashtray now!!!!!

Cool! Ive got a few ashtrays like that!

I bet if the holes for the exhaust bridge were not drill it wouldn't of broke.

iggys-amsoil wrote:I bet if the holes for the exhaust bridge were not drill it wouldn't of broke.

OKaaaaaa..

'82 cr480 and up can be used. Not sure about the differences, I am sure wiseco uses the same alm for all

The size of the intake port. Its larger on the older "480" style. The alloy is no different. You were prolly looking at a cast and forged aluminum side by side. An "old racers trick" was to port your motor for top end and run a 480 piston in it...

No use starting a new post but, will the old style piston work in the new style engine? New part number 13101-MAC-680, old part number, 13101-KA5-691.

The reason why I am asking is I can get the old style OEM pistons for a lot less money.

it'll work, the opening is the only difference.

dannygraves wrote:it'll work, the opening is the only difference.

Thanks, that's what I thought.