Engine type?

[Noidea]

I have a 73tx650 I tore the engine apart a because of a problem with no idle and came to the conclusion that it was the rings upon inspection I also realised the exhaust valve on the left side wasn't seating. I got new valves those are in and now Im searching for piston rings but not sure which ones to get because all the sizes are different and of all the bikes the one with the least information is the 73tx. My question is do i have the 256 or 447 type engine. On the chart for engine type it says tx650 (usa) the code is 366 and engine # s650-200101 for the regular one the code is 476 and engine number 476-200101 does that mean i have the 447? These are the rings i was going to get just want to be sure before i place my order. https://www.ebay.com/itm/YAHAMA-XS6...ash=item25e493dcc6:g:~wQAAOSwLVZVsktU&vxp=mtr

 

[TwoManyXS1Bs]

Noidea, I'd recommend caution in your '73. A wierd transitional year.
Best to measure what's in there, may have been overhauled before and who-knows-what put in there.

70, 71, 72 was 256 and 306 stuff.
73 had those, plus 366, 476, and 477.
Mid '73 saw a change to the valves.
Early '74 saw a ring change.
74-on was 477.

This last image, of the ring change, is somewhat disturbing, as it implies that there were 2 variations of 447 pistons, early ones with '256' ring geometries...

 

[650Skull]

The ID numbers quoted are from an ID chart.......... Have you checked your engine number to see what it is.

Some of the codes are odd to say the least, and they don't exist to my knowledge. I have debunked some of the ID chart engine no's that have been floating around the net. I think that 476 is not a valid engine or bike.

Looking for engine parts go HERE. been a lot of good feedback on their products from guys on this site who have made purchases

 

[MaxPete]

I just checked out that cruizenimage website - an amazing array of stuff for a remarkable range of bikes!

 

[Noidea]

yea I checked the number on on the engine it says s650-213689 same as the vin on the neck. Im not sure what that means in reference to type of engine I have 650Skull. Ive been doing some research and stuff and well based on the vin and measurment of my original piston rings (compression being 1.5mm will the double angle and the 2nd ring 1.5m with a single angle) I think i have 256. Question to toomanyxs1b's that it kind of scary seeing that information do you have a link or something so i can see more interesting information on the xs/tx's i would never known that information if not fro that and a quation if wanted better compression would it be better to get the new pistons and rings provided from the page you sent? or would it just be a waste and i would be better off with the original setup. and yes that cruzinimage site is pretty up to par I'll most likely be ordering my parts from there now thank you guys .

 

[TwoManyXS1Bs]

... the number on on the engine it says s650-213689 same as the vin on the neck.

...measurment of my original piston rings (compression being 1.5mm will the double angle and the 2nd ring 1.5m with a single angle) I think i have 256...

With that serial number, and 1.5mm thick top ring, you've probably got a normal '256' piston/ring engine. Measure the wristpin diameter to be sure. '256' will be 22mm.

Early XS650 serials and production numbers:
1970 XS1- S650-000101 to S650-006686 = 6686 bikes
1971 XS1B S650-007101 to S650-025383 = 18283 bikes (includes XS1F)
1972 XS2- S650-100101 to S650-133900 = 33800 bikes
1973 TX650 S650-200101 to S650-2?????
1974 TX650A 447-000101 to 447-012250 = 12,150 bikes

You can find early model service bulletins here:

http://www.xs650.com/threads/yamaha-xs1-xs1b-xs2-tx650-tech-bulletins-service-data-brochures.31022/

And more in-depth info on the rings here:

http://www.xs650.com/threads/xs-rings.133/page-2#post-393757