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FT500 Hi-Comp Piston


Virussuriv

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So i was doing my annual research on the stroker kit and landed for some reason in the wiki page.

In wich they mentioned that "Without increasing bore size, fitting an L28 with the longer stroke LD28 crank will only result in 2.9L.

In Japan and other parts of the world the popular "poormans mod" was the 3 mm~ overbore using the 89 mm ~ 90 mm Honda FT-500 / XL-500 motorcycle pistons along with the L14 rods.

The real poorman would use the much cheaper/heavier 89 mm FJ20 or even KA24 engine pistons.

All of these were cast pistons and had low endurance and would often fail when subjected to high compression and advanced ignition timing compared to custom forged pistons"

 

So i did i search in here and nothing, looked at my How to Mod.... (the bible for l28 mods) and found nothing.

The question is has someone really has done this or is this is another wiki error any input would be greatly appreciated,

cause looking at the piston and it does not seem like is hard to find specially with an overbore of 89 and the 90 mm.

They sure will be expensive to buy six of them but they really intrigue me as they look really well made.

 

Anyways heres a pic of one of them taken from ebay

 

post-3956-053848200 1295409241_thumb.jpg

 

post-3956-050108000 1295409256_thumb.jpg

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What wiki says is correct. "How to Modify" is American Based. The XL500 Piston/L14 rod is EXTENSIVELY documented in Japan and Japanese Magazines.

 

In 1989 you could get a forged Honda slug from the Honda Dealer for aroudn 2500 yen, at most $25, and a few years earlier due to the exchange rate, half that! With Rings.

 

The Weisco you have pictured will run you closer to $100 as shown with rings.

 

The XL pistons would either be 1.5mm down bore, or 1.5mm positive deck height (great with a 2mm head gasket...) depending on rod used.

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You sir is top ace in my books thank you for the info

Digging a little deeper seems like getting a hold of L14 rods is the hardest part of it.

The diff in the lenght is the only thing that can separate this from the L24 rod (correct me if i am wrong)

As for now i am trying to find specific info on the piston's Pin. Height and dish volume

 

BTW with the L24 rods the math seems very nice

Rod Ratio = Rod Length / Crank Stroke Length

L14 rod length = 136.5mm

Crank stroke length = 83.0mm

Rod ratio = 136.5/83.0 = 1.644

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Yeah, I think with the L24 Rod (133mm) you are 1.5mm down bore for a turbo, and with the L14 rod (136.5mm) you are either flush or down bore. And with the L28 rods (130mm) you are down some more again compared with the L24.... All very old stuff and all from recollection. Some of this may be applicable with the LD28 stroker maybe that's where the L28 rods come in if you want a shorter combination. It's been what...30 years? :lol:

 

The real deal was getting the pistons cheap. They won't be so cheap now, I was looking recently and found those Weiscos at the cost I quoted.

 

And yeah, finding an L13 or L14 anywhere nowadays is like combing the sand in the barnyard for Hen's Teeth! :(

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