anyone know the difference between '85-'89 - '90+ pistons?

dannygraves · Post by **dannygraves** » October 12th, 2007, 10:13 am

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

britincali · Post by **britincali** » October 12th, 2007, 10:22 am

No difference whatsoever as far as I know.

dannygraves · Post by **dannygraves** » October 12th, 2007, 10:26 am

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

LOVEMYCR500 · Post by **LOVEMYCR500** » October 12th, 2007, 11:13 am

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.

dannygraves · Post by **dannygraves** » October 12th, 2007, 11:15 am

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.

pstoffers · Post by **pstoffers** » October 12th, 2007, 12:16 pm

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

dannygraves · Post by **dannygraves** » October 12th, 2007, 12:45 pm

cool, but what exactly is the difference?

pstoffers · Post by **pstoffers** » October 12th, 2007, 12:52 pm

Danny Check your pm's

britincali · Post by **britincali** » October 12th, 2007, 12:54 pm

pstoffers wrote:Danny Check your pm's

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

ou812 · Post by **ou812** » October 12th, 2007, 3:07 pm

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.

iggys-amsoil · Post by **iggys-amsoil** » October 12th, 2007, 3:30 pm

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.

pstoffers · Post by **pstoffers** » October 12th, 2007, 6:43 pm

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

britincali · Post by **britincali** » October 12th, 2007, 6:56 pm

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

pstoffers · Post by **pstoffers** » October 12th, 2007, 6:58 pm

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

pstoffers · Post by **pstoffers** » October 12th, 2007, 7:15 pm

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

Its an ashtray now!!!!!

britincali · Post by **britincali** » October 12th, 2007, 7:17 pm

Cool! Ive got a few ashtrays like that!

iggys-amsoil · Post by **iggys-amsoil** » October 12th, 2007, 10:55 pm

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

pstoffers · Post by **pstoffers** » October 13th, 2007, 8:22 am

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

OKaaaaaa..

90cr500guy · Post by **90cr500guy** » October 21st, 2007, 10:49 am

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

M.F.D.B. · Post by **M.F.D.B.** » October 22nd, 2007, 11:31 pm

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...

robertg · Post by **robertg** » October 30th, 2008, 3:27 pm

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.

dannygraves · Post by **dannygraves** » October 30th, 2008, 8:51 pm

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

robertg · Post by **robertg** » October 30th, 2008, 8:54 pm

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

Thanks, that's what I thought.

BannedCR500Riders.com

anyone know the difference between '85-'89 - '90+ pistons?

anyone know the difference between '85-'89 - '90+ pistons?

Re: anyone know the difference between '85-'89 - '90+ piston