Piston ordered.  It was listed as for an NVT Rambler which used the DT175MX motor. 
I have had my eye on it for weeks, it is half the price of one from CMSNL, but knew if I ordered it, I would find bore damage and need a first over.

No box shown, just writing on the top showing yam part number and NVT part number.  I suppose people thought it may not actually be a genuine one and not take the chance.

Always say never miss a chance to educate others with important information they may require to get themselves out of a tight spot in the future.  Someone pipe up and tell us how there is irrefutable evidence that it is a genuine piston and a genuine bargain without a genuine box.


Piston pics











 

I believe that ART are makers of genuine Yamaha pistons, although previous castings of the letters that I have seen were on the inside of the piston.

Yes indeed.  ART make OEM pistons for Yamaha.  Good enough for me to believe the seller is correct in his assertions.

The Chinese are completely ripping off some companies. Usually they come stamped with an obviously Chinese oriented casting mark. But as of recently I've seen china mikuni's with the real mikuni casting on them. I've heard of ngk spark plugs having that issue too. Not too far fetched to think it's possible with a piston, although from looking at your pictures it "appears" to be of good quality. Not trying to point the finger either way, just throwing out my opinion!

Sat on the sofa this morning, sipping my favourite Arabica bean beverage, watching youtube vids and occasionally looking into the conservatory to give the devil bike the stink eye..

I have a couple of hours before my stomach will start growling and insisting on feeding, so I girded my loins, hitched up my pants and went to do battle with lucifers folly.

Engine on bench, ready for further assessment.  Not made my mind up whether to strip it at home or take it into work.


My word, the ally dust got right back into the intake.  Did not expect that.  The reeds stopped it going further.


A right old mess.  Not sure if it will need the crank pressing apart. That is a 0.020" feeler gauge between the thrusts and flywheels. Not sure of the max allowable, something tells me it is 0.015", but I cannot remember exactly after all this time. It looks and feels a lot, but not a lot of rock.  Edit.  Its fine, well within tolerance.
I need to get the crank out to mic up overall flywheel width before deciding on the next course of action.  I need to check it is true in any case.


Little end bearing looks fine, no discolouring or bits of alloy in it.  I have a new one in stock, so it will be discarded in any case.  I will reuse the pin.


The only score on the piston starts well below the rings, so happy to reuse them.


In respect of the new piston arriving, listed for a late 1970s NVT Rambler.  That little bit of knowledge resulted in a £80 saving over buying  from the dealer.  The holed piston was genuine in a yamaha box.  I will gladly do without the box....



 

I recently joined the "Hole in One " club too, with my 75 DT 400. What an honor. Welcome to the club.

Reading back through this thread.  It occurs that one member on here has been much maligned by a toxic character that is no longer with us for being errr toxic.

That maligned member being PJME and his motorcycle engineering business having to put up with someone spouting utter nonsense about his workmanship.  It was well documented on the 175 restoration thread that PJ had fitted a sleeve into my barrel a month or so before this debacle and he could well have done without a certain doomonger crowing when the piston blew.

It also occurs that I can do something about that and this thread is the place to do it.

Cue a pic of PJMEs work.
New sleeve fitted into old liner.  I had to look very carefully to see the fit line.  You are looking for a circular line in the dark coloured ring...  I can barely see it at all now it has been run and is the same colour as the surrounding liner.  Dunno why it looks brown in the pic though, it doesn't to the eye.  Just looks a normal colour.
edit.  It is the utility room lighting and the phone camera processing it.  Every pic taken in there looks brown.

And no, it never came loose or caused it to overheat.  I alone bear that responsibility.



 

LED and such are cold.
Better ones, are better in CRI, but old lights are so much better.

Although, camera eye vs. human eye is shiffty.

LEDS suck for the most part.

cliff

PRE-ignition.


cliff

Thanks for the positive post, 35 years i have been involved with making and fitting sleeves, there has always been lots of negativity around it, mainly by people who have either never had one done OR had one done badly. Also there are a lot that simply dont understand the process and poo poo the idea.

I have made and fitted well over 20,000 sleeves, that is since we have been logging it back in 2001 more before then. Thats a lot of cylinders!

Over the years i have learned to just let haters hate all while knowing the truth.

Anyway let me know if you need any help with your build 3.0