Author Topic: Trx250r piston (Read 3973 times)

Bhoycey · « **on:** September 21, 2016, 06:32:21 AM »

Hi guys I have blown my piston is there different pistons for the long and short rod engines. My engine is long rod I bought a trx piston but gudgeon to gudeon the piston I've taken out is quite a bit taller that the wiseco I've bought for it. Could the damaged piston be a yz250 piston if so what year of piston would it be thanks

Langbolt · « **Reply #1 on:** September 21, 2016, 08:29:02 AM »

Does the OLD piston you took out have a boost port on the intake side ? ('87-89 style) or a half moon a the bottom of the skirt ? ('86)

A 'YZ piston starts at 70mm and requires a 2mm spacer plate.

Do you know the year of your Cylinder ? '86 is wide open intake..... '87-89 has the vertical bridges.

Maybe take a pic or two and we can get you sorted out

Bhoycey · « **Reply #2 on:** September 22, 2016, 07:30:27 AM »

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Bhoycey · « **Reply #3 on:** September 22, 2016, 07:32:11 AM »

Hi langbolt these are pics of old and new id be grateful if you could shed light on where I have gone wrong thanx

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Langbolt · « **Reply #4 on:** September 22, 2016, 03:04:31 PM »

Looks like the OLD one was an OEM Honda Piston from an '86. ART made the pistons for Honda.

The New piston has the Boost port found in the '87-89 series Pistons.

Sorry Mate, You're gonna have to get an '86 style piston to solve your problem.

Please take a pic of the INTAKE of your Cylinder.....just want to confirm you have an '86 Cylinder too.

Did you buy a W562 instead of a W526 ?

Are you sure it's a long rod

What is Stamped on the beam of the connecting rod ? KA4 is Short rod 125.5mm & HA2 is long rod 130.5mm

http://www.eddie-sanders-racing.com/product_p/short%20rod%20125.3.htm

http://www.eddie-sanders-racing.com/product_p/long%20rod%20130.3.htm

Bhoycey · « **Reply #5 on:** September 22, 2016, 03:19:30 PM »

Thanks for your help it is running a Base plate and double gaskets when I stripped it. I bought 2 rebuilt engines one of which was ct 330 the other was supposed to be a 1988. From what I see it's more of a 86 piston I will get more pics tomorrow thanks again.

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Langbolt · « **Reply #6 on:** September 22, 2016, 03:46:09 PM »

Sounds like an Long Rod '86 Motor.....SO the Piston & Cylinder are from an '86 and the Connecting rod is from a '87-'89 which requires the 2 Gaskets & 0.190" Space Plate to take into account the change in piston pin height between those years,

If the Cylinder is a '88......then just run that NEW piston you have with 1 base gasket and NO SPACER PLATE.