1200cc ???

[steptoe]

 granted it is an old practice

Jonesy, don,t fall into the the trap of using a gumleaf, there,s to much variance,,

 much better to use a red iron bark leaf

[SCARFEY]

Brief explanation and good shots of the donk

http://www.youtube.com/watch?v=5wOXiYmDlg8&list=UU13b7sq1BCaaUj2MWOLNppw&index=4&feature=plcp

 

[makzy]

I've wondered that myself Scarfy, was watching them on tv one day and they interviewed some drivers and one of them said that an engine was worth about 8 grand! don't know whats involved in that 8 grand, but it would be good to find out if there was any bussiness in particular that built them, they are all built to a formullar...

[Jonesy]

Sorry Steptoe.....
I'm with Jeff on this one, rather measure with my micrometer to make that re-use or replace  decision

Although in saying that if I was stuck out in the bush with nothing more than a gum leaf to poke between the piston and bore to measure gap your "old fella's" method could come in handy

Back in them olden days they probly couldn't cast or forge a piston as accurately straight and round as they can in these modern times

Love
Jonesy.

[Christian Raith]

The cars are call Legend and use the FJ or XJR engines

http://www.motorsportworld.com.au/newsevents/news/aussie.htm

[SCARFEY]

I'm told those Aussie Racing Cars run 1200 Yamaha engines. It would be interesting to find out who builds the engines. They must have good knowledge on bearings etc.

[Christian Raith]

You mean 50 or 60 year old YOUNG fella's don't you

[excess.11]

Geoff........since then.......someone invented vernier calipers and other assorted accurate and inexpensive internal/external measuring tools.
I take note of the term........"old fellas".....phhht..........prolly some 50 or 60 year old geysers/codgers..aye?

[steptoe]

all pistons as well as being out of round are also tapered,,

a trick old fella.s used to use on an old motor to check life left, was to check the movement in the bore with the piston right way up, then put the piston in upside down with the skirt at the top of the bore and see how much more slap or play if any was present,, if a noticeable difference was seen, new pistons were put in

[Jonesy]

"the old turn the piston upside down in the bore trick"

------------------------------------------------------------------------------------

Righto tell more, whats this old trick all about?.........never heard of it

[steptoe]

 after 300k klm, it will be interesting to see how much wear there is in the bore, a good test will be "the old turn the piston upside down in the bore trick"

which is where the idea that a hone and new rings might be all that's needed as far as compression and get up and go, goes

between the thinnest and thickest bearing, the sizes vary by .0025 of a mm,{which is 1/4 of 1/4 of a mm} across the range, not between each step in size,

not to mention how the mains and littles are handling life in the fast lane 

I can feel a lengthy and involved video coming on

[petejw1966]

hey errol,
randy (davinci) on the .com site is selling
crank bearings (blue) heres a link
if ur interested, i bought a set of conrod bearings off him
a cpl of years ago.

http://www.xs11.com/forum/showthread.php?t=38360

[Jonesy]

Nuh no brawling here just putting forward my thoughts
Maybe something for in depth discussion while kicking a fire with beer in hand
too many intricacies to go into here in text.....mostly cos I'm a slow typer

[Eveready1100]

I've also found a previous thread of theirs where this subject was discussed in great depth - CLICK
Makes for a very entertaining read if you can follow mech tech talk.

As a side note and a real boost to my confidence of the piston kit, I've had a few chats with Tom about them, and it turns out he bought one of these recently and here's a snippet of his email to me

"Hi Errol

Yep I got a set of the cheap big bore pistons, I read all the pros and cons of the US site and some of the stuff they write is useful, most of it is complete bollox. My opinion of the pistons is that they are pretty damn good quality, I got my Toolmaker head on and did a full tolerance inspection, they're good pistons."

I feel much better now.

[petejw1966]

lol at brawl, no one fighting here,
i like to call it a discussion.   :-)

that could be the one,
and yep tom is very switched on.