You're good on the ring locating pins.

You really need to remove the feeler gauge. It's not hard to wobble and not slide it. Feeler gauge will make it impossible to test the wobble.

As far as the piston clearances.. I wasn't going to say anything as I don't know your experience and skills... In my experience and with my skills it's hard to get accurate repeatable readings with the telescoping gauges and a caliper. A dial bore gauge and micrometer is much easier and it's what I use.

Feeler gauge reading as mentioned by RT325 would be interesting... not accurate, but I'd be curious what size fit.

RT325 also mentioned something else... fin ring is LOUD on that model if you don't have all the stock little rubber blocks in place in between the fins... and most of the time they've fallen out... there's like 20 or 30 of them.

In summary, that piston looks great, if rod wobble is less than 2mm without feeler gauge that should be good, piston clearance by your measurements is good.... I'd run it. Wiseco is a great piston. Forged. Much stronger than stock. And yours looks to be sealing great, no signs of blow by past the rings.

Rubber blocks would quiet it down some... I think they are still available from Yamaha or you can make something similar from short pieces of rubber fuel line wedged in the fins to dampen vibration.

I will remove the feeler gauge and try the wobble measurement again.

My skills are sub par for sure haha
Unfortunately I don’t have access to a bore gauge. It did take a while to get repeated measurements with the tools I used.

Does rt25 mention sticking a feeler gauge between the piston and cylinder? I will read back and see. I can also try that and post what I get

I’ve seen all the YouTube videos I can find of these bikes and they all seem to have the “noise” some more than other of course.
I will also check if the rubber blocks are still available.

Thanks you all for the continued input and help

I wrote another essay & left it hovering when someone arrived, then lost it adding a pic. Anyway, here's a pic [if it takes as rejected it] of my TY cylinder with fuel hose or something squashed in there. Not sure if i did that or was like it but could do the head too. Other thing i lost was saying on my "86 kx125 it used to develop a rattle like that after a so many meetings of severe flogging--125 on full song all the time--& the gudgeon eye of the piston went egg shaped & had vertical movement you could feel by grabbing the pin & going straight up & down. Every regular genuine [in a kawy box] piston kit did it eventually & the original never did & reverted to that for the weekend meet if still waiting for a new one. Don't think for a minute that yours is doing that but easy to try while in bits. Get the pin right hole where it sits not 9/10 home. Anyway was only a thought.

Haha I’ll definitely try something like that on the fins when I put it back together.

I did order a few new gaskets and new piston pin and bearing oem stuff. Just to rule that out.

Slide the pin and bearing in the rod too--too compare old with new but pretty much never ware/wear there much, but in the early days of our DT2MX & RT2MX we had little end bearing cages break up. No real reason just a bad bunch of bearings that year maybe.

Stock was a bunch of little square blocks... one row near front and one row near back on each side. Some in the head fins too.

Pic is different model but same principle. If you look at fins you can often see where blocks were unless it's been repainted.







.

Edit

Found the part number for those rubber blocks
434-11161-00
Gonna order some. I think they could help with some of the noise

Found this pack of 10
hvccycle.net/yamaha-cylinder-head-fin-ab...ack-521-11161-01-00/

Hiya again, still following this great topic. I took some photos here and to follow of the blocks on my 175 cylinder & head before prising them out for repaint. I think there’s one missing off the head. These things definitely work let me know if you need measurements




Sent from my iPhone using Tapatalk

2 of 2



Sent from my iPhone using Tapatalk

Sent from my iPhone using Tapatalk