Wiseco pistons

[SON]

Like I said Piston of Last Resort
Use anything else First,
If nothing else available then use a Wiseco,
Warmed Run In and Clearance Checked.

[Lozza]

if you are going to run Seizeco do not use their piston to bore clearance (go wider) like as in you think your putting in a worn out piston run it in I mean as in really run it in, and use lots of oil, and rich on the carb then seize it up, cost me an Aussie title,
probobably best to get it ceramic coated better still get a few thou of ceramic put on you old piston as long as its in ok nick ie piston ring groove tolerances are in the servicable range

Bore it to Wiseco tolerances as per their instructions,
Run the piston as per their instructions,
Then pull it down again, wet rubbing any wear marking / high spots on the piston,
ALWAYS without exception warm up the engine before engaging the power band !!!

yep did that twice 1st time it tried to seize was on 1st start up it started squeeking after shut down when ya kicked it over, any who after 2 rub downs, was not happy with the marks appearing, so then took it out (honed) another thou or two, was assembled everytime with lots of oil, then run in alot, best part it didn't seize at the first race meeting it seized at the 2nd race meet

None of the above you bake the piston at 200deg C for an 1.5 hours BEFORE the cylinder is bored. Have used many old cast Wiseco's in the blue boxes after doing, never seized, even running at the edge of detonation. Worst piston increased diameter by 3 thou

[Brian Watson]

I wonder how may of you guys are absoluteley certain about air leaks..??!!I have run many "old" Wiseco without any troubles..and really..running more oil??....only makes the mixture more lean..remember... it is the fuel the cools..the more oil..the less fuel.. so LEAN.. no wonder it seizes...

[Lozza]

Massively altering the oil from 50:1(2%) to 20:1(5%) is only using 3% more oil, 1 jet is typicaly 3% change in fuel flow.

[popeye]

I've used plenty of wiesco pistons in both road bike drag bike and MX and never had an issue....
Yet I do no other people who have used them and had no luck at all...
I've also used JE pistons, Ross pistons, and Wossner as well all with good results...

[shelpi]

if you are going to run Seizeco do not use their piston to bore clearance (go wider) like as in you think your putting in a worn out piston run it in I mean as in really run it in, and use lots of oil, and rich on the carb then seize it up, cost me an Aussie title,
probobably best to get it ceramic coated better still get a few thou of ceramic put on you old piston as long as its in ok nick ie piston ring groove tolerances are in the servicable range

Bore it to Wiseco tolerances as per their instructions,
Run the piston as per their instructions,
Then pull it down again, wet rubbing any wear marking / high spots on the piston,
ALWAYS without exception warm up the engine before engaging the power band !!!

yep did that twice 1st time it tried to seize was on 1st start up it started squeeking after shut down when ya kicked it over, any who after 2 rub downs, was not happy with the marks appearing, so then took it out (honed) another thou or two, was assembled everytime with lots of oil, then run in alot, best part it didn't seize at the first race meeting it seized at the 2nd race meet

None of the above you bake the piston at 200deg C for an 1.5 hours BEFORE the cylinder is bored. Have used many old cast Wiseco's in the blue boxes after doing, never seized, even running at the edge of detonation. Worst piston increased diameter by 3 thou

nope wasnt any old blue box, what we used was new , and no have not heard of bakeing the piston and no, no air leaks, will not use Seizco ever again, no doubt there has been some success from wiseco or the company would not be in business, just funny how I had my 1st seizure after 40 years and that was after being well informed with the for mentioned info and by the way it was from older and more experienced motorcycle specialist raceing machine shops, so Ill just go back to the manufacturers item and if Im going to dabble it will be with ceramics.

[SON]

Wisecos 4 stroke pistons are OK,
It's the old air cooled 2 smokes that have been the problems
Especially the Dykes ring models,

[shelpi]

Wisecos 4 stroke pistons are OK,
It's the old air cooled 2 smokes that have been the problems
Especially the Dykes ring models,

agreed 

[davidmc]

haven't had any problems with Wiseco for years.

[sleepy]

Got to love the way all the Experts agree on this forum.
I've seen lots of siezed pistons and barrells of all makes. Ninty nine time out of one hundred the people that bored them either thought they knew more about what clearance to give a piston than the piston manufacturer did or they simple do not know how to measure a piston to get the correct fit.

[tony27]

The cylinder & piston arrived today, the 2 extra ports feed from the intakes & are nicely done. They look to be taller & steeper than the standard rear transfer.
The problem I need to sort is that the ends of the ring is midway across 1 of the new ports, a standard piston ends up with both end gaps over the new ports but there seems to be more meat available in the standard CZ piston for moving the pins. Is there a limit to how far apart the pins can be placed safely?

The new ports. Quite a bit of space between the main transfers & the boost ports to move the end of the rings to

[Lozza]

just funny how I had my 1st seizure after 40 years

Try harder 

The end gaps will run over those ports no problems if it runs through the middle of the port window. Don't move the pins it's a shite job and easy to go pear shaped.

[popeye]

Like sleepy says I think it's more a problem with incorrect clearances, or not chamfering the ports, in correct ring gap, air or water cooled bikes never had a problem, I've got 3 bike that running wiseco pistons at the moment and all going well...

[sleepy]

I'd have to agree with Lozza on this one. I would make sure you have good chamfers on the ports in question and from the photo it looks like all the ports need a little more work on the chamfers. Some motors have the ring ends over small port from new, one that springs to mind are the bigger Maico's, 400 have the ring end in the middle of the rear transfer port and the 490's have it across the de-comp port.
Moving the pegs is only a last resort job, almost impossible to get out the old ones and the pins are hardened with some small grooves up the sides that let the air space behind the pins vent. I've seen a few pin moving jobs end in disaster when they came out. Some of the early Wiseco's with dykes rings would end up with loose pins after a long hard life.

[shelpi]

Got to love the way all the Experts agree on this forum.
I've seen lots of siezed pistons and barrells of all makes. Ninty nine time out of one hundred the people that bored them either thought they knew more about what clearance to give a piston than the piston manufacturer did or they simple do not know how to measure a piston to get the correct fit.

give Dave Dyson a ring and tell him that, do you know how long he has been in the raceing business?