XS650 build.

[BrokeAss]

Crank it over and check compression, if good then upgrade the electrics to PMA alternator and electronic ignition. Only way to go with these motors...

[Northerner]

Back at it.

I’ve broken the engine down and discovered a few things I’d like opinions on. I also found a cracked friction plate in the clutch. I’ll post photos with questions

[Northerner]

Here it all is “organized” and labeled. Going to clean it all, replace seals and gaskets etc..

[Northerner]

I don’t think this is normal. Just looking to confirm some kind of modification has occurred here. Any guesses as to what?

This is the opposite side. Outer part of the lower crankcase.

[Northerner]

Some repair work here I’m assuming? This is a close up photo.

Another photo showing the same thing just further back. It’s where the kickstarter shaft inserts if I remember correctly.

[Northerner]

I guess I’m just looking for info on if this is big trouble or something minor. I know I bought a basket case and half expected stuff like this.

[mcknzAlex]

It's been years and I am surprised that you're not yet done with this build. Maintaining a classic bike nowadays is hard.

[SaddleTramp98]

Not sure what's up with your case, maybe someone on here more knowledgable can help.
You can probably find another on ebay if it turns out you need to. Since you got the whole thing apart you might as well do a big bore kit on it.

[Northerner]

I’ve looked around and it’s just a starter elimination job. I’ll plug it back up with a freeze plug, what I’ve seen on some forums after looking around. All the big bore kits I see are for 1974 and up. I believe mine is a 72. Not sure what the difference is. I think Heiden tuning has the big bore for early models but there around €900.

[Northerner]

Still not sure about the repair work. It’s where the kick start shaft inserts.

[TriNortchopz]

All the big bore kits I see are for 1974 and up. I believe mine is a 72. Not sure what the difference is.

256 vs 447? Here we go...
"- the numbers are cast into the conrod
256...136mm conrod, 22mm wrist pin, 26mm crank pin, no starter cog...306...same with a starter cog
447...130mm rod, 20mm wrist pin, 26mm crank pin, starter cog
533...140mm rod, 20mm wrist pin, 29mm crank pin...mostly sold in europe

- because the bores and strokes are the same each crank type has its own pistons...the cranks can be swapped complete with their rods and pistons...there are other differences in the motors-compression ratios, clutches, cam timing, gearbox etc .."

http://www.xs650.com/threads/256-vs-447-here-we-go.1204/

Technical Stuff

TORQUE AND REPHASE THEORY
XS650 CAMS
WHICH OIL TO USE
YAMAHA XS650 HI PERFORMANCE GEARBOX MODIFICATIONS
880cc ENGINE BUILD
CYLINDER BORES AND PISTON RINGS
MODIFYING THE ADVANCE AND RETARD MECHANISM

"(All crankcases from 72-84 are essentially identical, only XS1/B cases are different). For this build I purposely chose the roughest set in my spares stock to illustrate what can be done with a little hard work. Inspect them carefully for damage, the kick-start lug breaks, damaged threads, and very rarely cracks near the studs."

"The 880 kit can only be used with a 533 crank. This crank was used on European only XS650 engines, it has a larger 29mm crankpin, and the connecting rods have 140mm centre. This gives a rod to stroke ratio of 1.89:1 which reduces piston side thrust loads, and subsequent wear rates. Ensure you have a 533 crank; the 447 and 256 cranks will not work with the 880 conversion. If your crank is in excellent condition it can be re-used, but if it is in any way suspect then replacement of the worn parts is recommended for long engine life, these engines are very high torque and will “spit out” any suspect parts. "

http://www.smedspeed.co.uk/tech.html

[farmall]

I'd avoid throwing money at any 650cc twin since the best way to get HP without buying oddball wear parts whose replacement requires yet more oddball wear parts which may no longer be available years down the road is buy an engine that makes HP in the first place.

Many bike builders "chase statistics" when they benefit much more from simplicity and reliability. It's also a good idea to hoard stuff like spare engines if keeping a machine and the earlier ya score them the better deal ya get as supplies dry up over time. An engine is not a marriage and if a better deal comes along there's no reason not to pounce on one needing less work.

[jervinLX]

Looks like an interesting project! Subbed

[kripalwe]

[ATTACH=CONFIG]98899[/ATTACH]

Just brought this home and it will be the starting point of my first real build, looking for advice and guidance along the way. The first thing I want to do is get it running and then I’ll work on getting it to be rideable and then I’ll plug away at the details. I have a set of carbs that came with it but unassembled the motor turns and I was told it will produce spark. What would you all do at this point?

This looks so fabulous and I loved it.