well... it's not easy to replace the piston and rings if your not too mechanically inclined...

150 bucks for a Wiseco 97mm piston+rings+wristpin+c-clips:

Wiseco Piston Kit Yamaha XT600 84-96 97mm | eBay

YAMAHA XT600 WISECO PISTON KIT 1MM OVER XT 600 84-96 | eBay


The first link, the seller says he also sells the top end gasket if you need it..

Three hour labor is more than enough to get the old piston out and fit the new one in NOT counting the time/money for to rebore the cylinder sleeve...


Vando

Vando,
97mm is about 4th oversize, the early XT's were 95mm bore and then went up in m.5mm sizes.
Quicken,
This is not a difficult bike to work on and should have the barrel taken off and measured before buying the replacement piston, look for oval or badly scored bore.
Like Mezo said,
get a rebore, do it properly and you will reap the rewards with a Great bike.

__________________
I'm not getting older; I'm just progressing through LIFE!! Harleys do not have a throttle- they have VOLUME control!!!

Oh.. Ignore the first link on the previous post of mine.... I thought they were 96mm stock.... my bad... STILL, link #2 is a valid option!
Still, if his engine is burning up that much oil you can surely skip first size up and go to the 2nd size overbore if it's in that bad shape..


WISECO 96mm:

Stock compression: Wiseco Piston Kit Yamaha XT600 84-96 96mm | eBay

High compression: Wiseco Piston Kit Yamaha XT600 Hi-Comp 84-96 96mm | eBay

Keep in mind, +1mm overbore is in diameter! so it's 0.5mm increase from center to wall..


Vando

Thanks for all the information guys. I think the milleage is REALLY high, but got the bike for a real bargain (Equivalent of 250 pounds) and it actually still runs very well for it's age. I was really hoping to just replace the rings as I would have to find an engineering company who can do a rebore for an oversized piston, but it seems that it might be the obvious solution to do so.

The Yamaha dealers around here charge an arm and a leg for parts, if they can still source them (and if they are prepared to help as customer service sucks in this country) so I agree with you Mezo that I'd rather try and see if can find an oversized piston and someone that knows what they are doing when it somes to reboring the engine....will be nice to have a bit more power from the old muel.


The price of the Wiseco kit is really not bad seeing as replacement rings for the existing bore and piston will cost me half as much, so it might just be worth the effort. I'll also just respray the block with black engine paint while I'm at it to give it a new look....all the paint has sadly dissapeared over the years.

I am aiming to rebuild this bike completely but it completely depends on funds and time at this stage. I also use the bike quite regularly to get to work and back so that leaves me without transport for a while.

Thanks for all the VERY helpful information guys. I really appreciate that I can come and ask for advice from people who know what they are talking about.

Thanks bacardi, I checked out the updated links. I'll have to take chucky's advice and I think I'll have to open her up and check the current bore diameter first (will prove to be quite a job I suppose).

I think this bike has been through many owners, and it is very possible that someone has already rebored the engine to a larger diameter.