Piston's

nmdesertrider · Post by **nmdesertrider** » December 17th, 2010, 9:06 am

Rumor has it that Wiseco are being made now in China- and they are heavier than they used to be.

http://www.youtube.com/user/500bigbore · December 17th, 2010, 9:29 am

china yes, weight not too much. I've seen 6 different versions of the wiseco now

the last one with cuts was 374grams, the newest coated one is 410 grams, stil 21 grams lighter than the full round version.

They're getting better tho. This coated version has material reinforcing the skirt in better ways and hepls to keep it round as it grows.

I'm considering a coated style wiseco for my next engine. I'll lighten it tho

dubious01 · Post by **dubious01** » December 17th, 2010, 10:16 am

My custom turbo pistons for my zx14, with ceramic coating top and sides were $650 , for 4.... no rings included

100hp honda · Post by **100hp honda** » December 18th, 2010, 2:51 am

box still says made in usa. maybe some are made in china but i dont think all are. atleast not yet

Post by **AlisoBob** » December 18th, 2010, 9:15 am

Maybe just the box was "Made in USA".

100hp honda · Post by **100hp honda** » December 18th, 2010, 1:33 pm

checked these 2 wiseco. i can tell you theres less than .0005 difference between them. nearly exact on the bottom skirt, about .0003 90* from wristpin. im putting in fresh plating so this doesnt meen jack shit to me. if i was putting them in a new cylinder then obviously they would need to be a certain size. i have no idea what size a new cylinder is so i cant say whether these would drop right in with proper clearance. i doubt they would be very far off but you never know.

NightBiker07 · Post by **NightBiker07** » December 18th, 2010, 1:35 pm

100hp honda wrote:ya bob, how do they make more power ?

only 1 reason guys dont like wiseco.......... because theyre too fuckin dumb to know how they work. . not meening bob in particular but people in general. half the blame goes to machines shops. alot of so called professionals out there that cant bore a hole to save their ass (gss is good example, but certainly not the only example), customer doesnt double check the work before assembly, half way down the driveway the damn thing is froze up. how is that a pistons fault ?? tell me that. seems me and Pstoffers the only mofos on the planet able to run wiseco for years on end with no siezures

Ive had a wiseco in my 250 for 3 hard years. When it lost compression, the piston and jug was SPOTLESS except the ONE spot a piece of bearing managed to tear up the cylinder wall/piston.....

riverman · Post by **riverman** » April 16th, 2011, 1:34 pm

I bought a Vertex. Nothing ventured nothing gained. Bsides I can blame Bob if it's bad.

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Now 3 to 4 weeks wait at the machine shop. He said I'm a little behind.

Gmbond · Post by **Gmbond** » April 16th, 2011, 3:05 pm

I went 90mm vertex also. Haven't ran the bike yet. Lol

Couldn't beat the price for the vertex kit, and Roosty seems like a standup guy who knows his stuff and he recommends it. I didn't buy from Roosty, however even tho his price was good. I went local for the piston and bore.

Post by **AlisoBob** » April 16th, 2011, 5:11 pm

Take your Vertex, and sand a light chamfer on every edge that contacts the cylinder... even the gudgeon pin relief.

Sand out all the imperfections on the underside of the skirt and pin boss area.

Get some quality machine work done

Clean everything until its spotless. I like to use PAM. It gets ALL the micro-grit out.

Put it together with LOTS of two cycle oil. I even dump extra oil in the crankcase on top of that. Start it up with the choke on... and leave it on!

Its going to smoke like a bitch, but who cares. Run it till it gets hot with the choke on. You want extra fuel and oil in there while everything grinds together....

You'll be rewarded with a top end that looks great , even after years of service.

seanmx57 · Post by **seanmx57** » April 17th, 2011, 1:00 pm

what's the point of sanding the interior imperfections? Sleep better

Post by **AlisoBob** » April 17th, 2011, 2:38 pm

Imperfections = stress risers = potential cracks

5 minutes of work = no worries

Okotokian · Post by **Okotokian** » May 11th, 2011, 1:04 pm

Well the 94CR500 was running good with the PJ.
Was time for a top end due to low compression (Wiseco at that time).
So I had Millemnium Tech bore/coat the cylinder and size up a ProX for it.
I also ordered a 39.5mm PWK. Ripped it completely apart and double checked everything.
Result: Broke it in as per Bob's procedure and is great from 1/8 throttle to top end BUT it will not idle.
I've tried 40, 42, 45, 50 pilots with the air screw 0.5, 1.0 1.5, 2.0, 2.5 turns out and it still dies.
More specifically: I tried again with a 42 pilot, a/s 0.5 out, 1.0, 1.5 out, 2.0 out 2.5 out with the choke on and all it does is idle for 30 secs and die. I have to give it a small amount of throttle just to keep it idling. The black plastic screw is all the way in and does have the slide opened a small amount.
-If I feather the throttle to keep it going for 20 secs then turn the choke off it completely dies every time...
Slomo on the other site says that the ProX does not completely cover the exhaust port and will therefore have idling issues. I am friggin dissapointed for sure. Spent full days on the carb alone and have gotten nowhere.
As I said, it ran great before redoing the top end...
Any feedback on that? I'm going to St. Anthonys sand dunes tomorrow with a CR500 that can't idle

blownbillybob · Post by **blownbillybob** » May 11th, 2011, 1:26 pm

Did you try putting the pj back on to eliminate the pwk seems like everything you did to the carb didn't make a difference, what about a vacuum leak, it could also be possible that when they assembled the carb the o-ring in the jet block got buggered up

Okotokian · Post by **Okotokian** » May 11th, 2011, 3:08 pm

I pulled the jet block off as well, blew all 3 ports/circuits out (they were clear anyway). The jet block gaskets are all nicely glued in place. Every port/hole/britincali on the carb is clear and clean.
She's all paddle tired up and in the truck. It'll just have to feather the throttle all weekend.
I'll put the PJ on some other time, then learn the leak down test I guess.

Post by **AlisoBob** » May 11th, 2011, 3:58 pm

Theres a brass idle speed screw available for the PWK. It opens the slide slightly more.

You can also clip a little off the spring, so the black plastic screw raises the slide slightly more too.

Try either one, the snipped spring is free and will probably do the trick.

Yea, Pro-X has got issues.

Vertex all the way.

100hp honda · Post by **100hp honda** » May 11th, 2011, 4:34 pm

thought prox only had a problem if the port was widened ? personally dont think thats your problem though. is it new or used carb ? be real cautious of used ebay shit. lord only knows what backyard modifications someone may have done. if its new im a little stumped. can you barely hold the throttle open and it idles steady at 1000rpm or so ? to me that suggests the plastic screw aint holding the slide correct. not sure about the airleak. had massive airleak on mine and it still idled.

Okotokian · Post by **Okotokian** » May 11th, 2011, 8:32 pm

I was reading old posts (3 times) of Bob's on the other site that said ProX was the way to go hehe! And thats what I installed.
The carb is (almost new) bought from the guy on Ebay who has been selling a CR500/lectron carb methanol engine for a hefty price. It's honed to 40mm, seems good just can't idle.
I was thinking about cuttiing the spring too. Good idea Bobby.

2strokekyle · Post by **2strokekyle** » May 11th, 2011, 8:57 pm

Bored carb?? The slide isn't "windowed" is it?? That would make it lean at all but WOT, it would be leanest at low slide openings. I had a pj punched out to 41. It was worthless for all but wide open. It had a 58 pilot I think and it still only idled sometimes...

Okotokian · Post by **Okotokian** » May 11th, 2011, 9:51 pm

Hmm interesting. The 6.0 slide seems unaltered. Ebay seller "formulaguy" described it as follows: "Brand New 39.5mm Keihin PWK carb, smooth bored closer inlet of 40mm. Nice power add on."

-When I get to the dunes I'll throw in a 55 pilot, I have a 60 as well.
I know 50 seemed the worst but I really couldn't tell the "much" difference between the 40 and the 50.

coley13 · Post by **coley13** » May 12th, 2011, 12:28 am

Bob that steak on the PAM can is seriously under cooked...

blownbillybob · Post by **blownbillybob** » May 12th, 2011, 7:16 am

I got a pro-x in 2 of my trail bikes with a stock port with, and a stock PJ and it idles all day long, now I'm not saying the piston is not the problem but I would switich out carbs before a piston?????

quicfix500 · Post by **quicfix500** » May 12th, 2011, 8:28 am

AlisoBob wrote:Theres a brass idle speed screw available for the PWK. It opens the slide slightly more.

You can also clip a little off the spring, so the black plastic screw raises the slide slightly more too.

Try either one, the snipped spring is free and will probably do the trick.

Yea, Pro-X has got issues.

Vertex all the way.

Do the idle screw trick first, takes 2 minutes . no excuse not to try it.

BannedCR500Riders.com

Piston's

New top end with ProX won't idle