Yamaha XS650

Engine out , bloody thing is heavy enough to anchor a large boat amd I will dtop the forks and yokes tomorrow and strip the frame of any rust and get a coat of etch primer on it .
As for the motor the oil was like treacle and looking at the drain plug magnets and the low compression I think it will be prudent to lift the head to see what the bores and valve stem oil seals are like.
Oversize pistons are £220 and a 706cc conversion kit is £200, might go deeper and see if I can get the notoriously troublesome electric starter working
 

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Neil,
If the bore's are shot let me know, as my friend in Rotweil used to sidecar cross the XS motor, but bored to 850, and he still has loads of spares
 
It’s a long time since I had my XS2 but from what I remember they won’t stand much boring before the liner gets very thin so I went a bit mad and fitted 750 pistons with new liners and bored the barrels out a bit. There was no work needed on the heads to accommodate the pistons but any over sizing of the bores puts a lot of load on the little end which on the XS2 was just a pin in the rod with no bearings so there’s no solution if they get a bit baggy.
 
The bike hasn't had a working electric starter for as long as the previous owner had it and when it was rewired over 15 years ago the solenoid and wiring was removed.

The starter is still in place but when I pulled the starter cover all of the gearing is missing, however, having powered up the starter with jump keads it is fine do I may look for the internal gears and try to reinstate it
 
Pulled the head and barrels off the engine this morning to look at the oil burning issue, on checking it is on 0.50 oversize, the piston crowns are heavily carbonised so it looks like the valve stem oil seals might be the issue .

The bores ,pistons and rings all look fine but I have given the bores a light hone so they should be good to go. Bike is already fitted with a new continuous camchain and tensioner blades.

Engine has a number beginning with 447 which seems to indicate it is US spec ,however, on checking the con rods they are marked as 533 so the motor is definitely a Euro spec long stroke one.

Need to get one of the exhaust studs fitted with a Timesert insert and will lap in the valves and fit new valve stem oil seals.
 
Well the pulled out helicoil means that the hole is too big for a Timesert so the hole is getting alloy welded and then drilled and tapped back to standard, also on double checking in better light there is actually a mark on one of the bores so new 0.75 or 1.00 oversize pistons are needed
 
I have the 0.75 over piston kits in the garage , head is back and the front end is fitted ,today I made up a new front mudguard bracket and will try and get the prep work done on the tank and mudguard in the next few weeks and then strip it and get the frame either painted or powder coated .

Aiming to get it as a functioning rolling chassis in the next month or two and then get the motor rebuild completed when the weather gets warmer .

Will get Saddlecraft to re do the seat into a standard profile
 

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The Yamaha XS650 was a mid-size motorcycle that had different models and generations over the years. The standard model had spoked wheels and a flat seat, while the Special model had cast wheels and a stepped seat. The frame and geometry were mostly the same for both models, so you could restore it as a standard bike if you prefer
 
I always wanted the XS650B, the one with twin discs up front. I actually bought a Honda 400/4, I didn’t have it long as I thought it was hugely overrated by the media so I sold it and bought a BMW R75/6, a cracking bike but I still would like an XS650B :rolleyes:
 
I always wanted the XS650B, the one with twin discs up front. I actually bought a Honda 400/4, I didn’t have it long as I thought it was hugely overrated by the media so I sold it and bought a BMW R75/6, a cracking bike but I still would like an XS650B :rolleyes:

I’d have another 650 if one came up at the right price but not one of those horrible US Special pieces of shit that we had foisted upon us :barf

I’m biased and still prefer the older XS2 but a 650B would be nice.
 
I’d have another 650 if one came up at the right price but not one of those horrible US Special pieces of shit that we had foisted upon us :barf

I’m biased and still prefer the older XS2 but a 650B would be nice.

We both had a XS2 so I'm sure you can also remember the frame was shit, very bendy!

Tank slappers regularly too.
 
We both had a XS2 so I'm sure you can also remember the frame was shit, very bendy!

Tank slappers regularly too.

That’s what I loved about it and why I’ve still got a Kawasaki H2. Bikes should be exciting :D
 
Pulled my US Custom out the barn , I’ve got all the bits just need space to get it in the garage .
 

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Intend to get back onto thus build in the very near future , once the 1150 is on the road, I have the pistons and rings etc and then will make a list of the rest of the bits needed.
 
Spooky one appeared on the XS650 facebook page today with someone after a rear light cluster for a 650 same as one that they had fitted to a bike they built in 1991 , they posted this photo and surprise surprise it is the same bike I now have in my garage
 

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