No longer avaible from partslist, 3TB is avaible and price 360dollars..So yes EBAY, i recon JJ have one for you? Hard to tell how its possible to make the scratches in that area, didnt happen when engine was on bike running. Yamaha 1988 XT600 XT 600 Engine Cylinder Jug Barrel Piston Set | eBay

I've milled off most of mine when I rebuild them. Most I just take 2-3thousanths, I have taken .015 off one(the head, not cylinder but can do the same). The timing is effected a little, it goes retarded some but not enough to have running issues. If you need/want to take more off getting a thicker copper gasket can bring back the height, I don't know what would be the limit , I use .043" copper as a oem replacement, I imagine .0625" would be my max thickness.

I actually do have 1 or 2 or 3 heads/covers here if you need a set ,plus a freshly bored cylinder and matching Wiseco piston. Need a complete running motor ?

Oh and for the temp sensors , I use 6mm x 1.o Trail Techs , either the individual TTO readouts or the Vapor computer,
http://www.ebay.com/itm/Trail-Tech-T...580acd&vxp=mtr

Do you think this is the reason behind the blown gasket?

Motor has new piston/jug/valves/chain from previous owner.

I ordered a new gasket yesterday, will it still be of use if head gets milled or would I need to not open in case a thicker gasket is needed.

This puts a tamper on things.....

It'll work as long as not much is milled off, that's a likely cause of the blown gasket. It's impossible to tell how deep those marks are with pictures. If it can be kept to less than .015" then there won't be issues with the oem gasket , it is tightening up the squish but still workable and timing won't be off too bad. Wait to open package till head is milled.

Just remember when reinstalling, the timing marks on the cam won't end up perfectly even, the chain is newish so that'll keep it within reason. If they need to take more off then you'll need a thicker head gasket, or a thicker base gasket and a bit turned off the piston top to get the proper squish back or pre-detonation can start easier.

Can you measure how far from the top of the cylinder does the piston come up to? In you picture the piston appears to be almost even with the cylinder top, it should be more in the .03" area ideally on these.

its a weiso piston in there would that change the measurement?

Clean the top off and get the number stamped on it. If it's a std comp piston it should still be close to .03", a higher comp will be closer but either way it shouldn't be less than .015" with .02" better.

What do you use to clean the piston top?

Got a wire brush ? Some degreaser or carb cleaner works but with it still on the motr you don't want a bunch of junk going down. Should be fairly easy to clean of with a wire brush, just don't get too aggressive.

The piston does appear to be a standard comp , being that it's a flat top.


EDIT, after looking at some pistons I have on hand for the XT, your does indeed look to be the standard comp due to only 2 valve reliefs on the exhaust side and the slight dish(far right). The 10.75:1 101mm(middle) that I have is completely flat and has all 4 valve cuts so will be only approx .015" below cylinder surface. The 11.5:1 102mm JE is quite different (Left) still will be .015" below cylinder at the edges,

http://imagizer.imageshack.us/v2/800...673/qwgT9j.jpg
http://imagizer.imageshack.us/v2/800...911/FuSKMZ.jpg

Any ideas on cost to mill a head?

For me zero ,I do my own machining, don't really know what some will charge, maybe $50, maybe be $100( shouldn't be, but some areas??). Get a quote first from a local machine shop . Make sure they'll do it for a set price up front so no surprises. Otherwise send it to me and I'll do it. Can't remember where your from.

NY

See if you can have someone local do for a decent price, shipping will still cost a bit may $30-$35 both ways, plus a bit of down time.

Thanks i'll look into it

I also feel I need to replace the rocker head because I've had rocket noise for last 2000 miles :(

We all have rocket noise :clap:

Speak for yourself, mine don't have noises , mine have rattles :innocent:
,



Ajax , depending what and how loud your rockers are it may just be one or 2 getting on the loose side and in need of adjusting. All theses motors have some rattling to an extent, it's the design. There is a limit but there have been that make just an awful rattle from new, but live a long life with no issues.

Also that Wiseco piston is a forged slug , it usually has another .001"-.0015 clearance in the bore for expansion, compared to oem, so can have a bit more noise. Depends who bored it out and what they used for tolerances.