PISTON HELP

HI ALL I HAVE BEEN LOOKING AT PISTONS ON THE TKR PISTON WEB SITE .THEY SHOW A PISTON PLUS ALSO EVERY MEASURMENT.HAVE HAD A LOOK AT TZR .ALSO VR 150. BOTH YAMAHA.VR 150 MEASURES BORE 59.0 .LENGTH 66.40.PIN 16.COMPRESSION HEIGHT 33.40.30.0 .PIN LENGTH 16X50.5.THEY ONLY DIFFER IN LENGTH TZR 66.50 AND COMPRESSION HEIGHT 33.60.30.0.IF ANYBODY COULD HELP .I DO NOT WANT TO COCK UP AGAIN.IF VR PISTON FITS IT WILL FIT STRAIGHT FROM THE BOX .THANKS.

I don't really understand why you don't just use the standard type of piston Nige,
if your still talking about a 125, I used one to race, go to work and to play with.
4 two years open carb 10000 RPM none stop everywhere never had one fail on me m8

cheers.my barrel is at chiselspeed at mo . they have me a piston ported yamaha piston sorted.135cc i think .they are making me a leg burner expansion pipe aswell so hopefuly a real goer .my old borgo piston had chrome rings and to be honest the barell what was used with that piston as only got slight score marks on exhaust side .did you ever use chrome rings

yes I 'e used them but the problem is the bore wears-out first - not so good with cylinders
now getting so hard to come-by and rings can be obtained easier than cylinders can.
So for preference this time I'm using a loose competition steel liner just to
run-in then I'll copper and chrome the liner to make the interference-fit after.
So for a while I'll be running it with 3 loose sections plus the head and liner,
only held in-place by the head nuts - I've had to make my own cylinder because
of not being able to obtain a J 125 one, which I'd have preferred but the times not been
wasted though (I hope) .
This one will have a seven transfer port system and computer style cooling for optimum
power, hoping for about 40% cooler running, by my reckoning anyway.
I just have to finish cutting out the ports in the liner and we're done - fingers crossed
Good to hear yours is now finally all coming together too m8 - nice one,
(maybe we'll form a club team) Ha Ha

very trick .you dark horse.sounds like something wildcat might have done.have you got les raffertys lost note book .very skillful and complicated .that should fly when it is done .race ya

mine's a little different from les's first I have the sleeve in the centre of the barrel at the top AND
at the bottom a minor point ha ha, also it's 8 port not 5 Nige but I'll be well happy if it goes as well
as my old J one's did, nothing wrong with them and so so very reliable more importantly.
It should be ready by the end of this weekend - so keep your fingers crossed for me m8

wow littlewilly any chance of you writing a book on two stroke tuning
i think you must be the (missing link) on lambretta tuning 10000 rpm
j ranges ,loose sleeved ,seven, or was it eight transfer port cylinders,
its just what everyones been waiting for, any chance of some pics
of the cylinder or diagrams or details ,or are they secret & just in your head

A wildcat 5 port had 4 transfer ports + an exhaust = 5 port, of course there is an inlet
port also, in a piston ported engine but only the ports that are exposed when the engine
is @ BDC are counted when describing a cylinder.
Mine has 7 transfer ports + an exhaust port = making it an 8 port cylinder
I am not by trade a scooter tuner, although I have done some experimental work for a
a small one man company at Watford Hurts but he moved up north with the business.
a very polite lad who asked me to help him when he wanted a new type of 225 cylinder.
Almost any member interested in a look at the new cylinder can, I will PM photos on request.
after this weekend it should be fitted together for running-in.

P S I wont be displaying them in the forum in case the wrong person sees them

LITTLE WILLY .ARE YOU TERRY SHEPERD

oo yes id like to see some pics of the barrel littlewilly i like a nice bit
of engineering . i think he,s arthur himself ,come out of retirement

OR DID YOU HAVE SOMTHING TO DO WITH AF BULTACO CONVERSION MAYBE.COME ON WILLY WHO ARE YOU.

I don't remember even having a chat to Arthur, I'm just a semi retired engineer, rebuilding

old classic engines 4 people these days.

sounds like some hard quality work has gone on with that cylinder, good on ya.

any progress on the mega port monster barrell willy i cant imagine this sort of
groundbreaking lambretta tuning , especialy eight ports around such a small cylinder
must be time consuming (engineering & mental) to produce, it took a week of tuning & grinding
to produce 1 ,5 port barrell so yours must have taken ages ,good on y willy it must be hard

i know, yer willie wonka arent you

drat drat & trebble (3 port) drat ,i knew this info was secret , youve certainly
dreamed alot about this .

All I can say now is, it starts first time & runs - but I'm a little bit concerned whether
the forged, high silicon, chocolate piston can take the thermal loadings @ speed

looking foreword to the,, proof ,pics .. or lack of anything

Any news on this exciting development yet littlewilly or just another good idea that's run out of steam ?

No steam just a little vapour maybe, running temperature is very low which is pleasing but as it's
not been used in anger, so that's not very conclusive. I've been talked into doing another cylinder
for a friend, who says he'll forgo the (pre-assembly) running-in process so's both barrels sleeves
can be plated 4 pressing together at the same time.
It starts and runs nicely, the port timings are tried and tested and the temperature innervations
seem effective (so far) though, I will be adding some T5 type spacers to support the copper fins
in place later, as their only 1mm thick all the way to the cylinder sleeve