Vin issues motor issues

[Timmy hutts]

Hey people. I have a xs 650 bobber. Just ordered a bunch of 447 big bore parts to pump up a dead engine. Pretty sure I messed up because now that I have it a part one of the pistons says 256 on it. My head tube says s650-024946. If it is a 256 engine do I need to order rods to make everything work. I already ordered 750 cylinders and pistons and a cam to go with it. To the obi wan kenobis of the xs world help.

 

[Jan_P]

I have not heard of Pistons being marked with other than dimension -Is it not 956 on the top ???

 

[Timmy hutts]

It says 050 on the top and 956 on the side of the piston.

 

[Jan_P]

OK I am out here :Not seen that before ..not so familiar with the earlier motors
Someone else Chime in
My guess it is not Stock Pistons .And are looking fine on top .
Wild guessing again oversize ? Do you have possibility to measure diameter and Piston pin diameter.

 

[Timmy hutts]

Piston is 74mm and the piston pin was 20 mm. So I did a quick little read and everyone is saying 256 pistons are 74 mm. What do I need to make the 447 parts work. Fml

 

[Jan_P]

Well this is difficult I do know that between 533 and 477 motors there are some differences
Not familiar with 256
https://www.xs650.com/threads/447-533-pistons-whats-the-difference.7222/

The pins are in a differant position on the piston, the rods on the euro xs's are differant length, still the same bore and stroke though,

533 are the euro

447 are the rest

If it was me I would look up a parts Schematic manual online and start to compare Parts numbers.
If the same OK different Not So Perhaps someone else chimes in here online

 

[650Skull]

Engine no indicates it's an XS1b. Does the engine have provision for an electric starter motor on the crankcase

Measure the distance from the top of the piston to the pin hole position.

 

[650Skull]

That looks like 256 to me

 

[Jan_P]

Not to complicate

But Piston is 74mm and the piston pin was 20 mm

Not in the picture for a 256 .. If I see right are larger ..

 

[Timmy hutts]

That looks like 256 to me

That looks like 256 to meView attachment 242116View attachment 242115

Yeah that’s my bad forsure. Just gotta figure out how I can make it work.

 

[Timmy hutts]

Not to complicate

But Piston is 74mm and the piston pin was 20 mm

Not in the picture for a 256 .. If I see right are larger ..

Yeah I guess bottom end is coming a part. It burned like 3 litres of oil in 30 minutes trying to get it home. Figured valve seals and a top end would be on point. Guess not.

 

[Jan_P]

Just putting it out here as food for thought.
Splitting the crank is a Big Big Big job Maybe .a 5 -6 -- 700 $ US A lot can go Wrong.

Those pistons there looks almost new ..By the few pictures I may be wrong and you can have cleaned them.
But it looks as if someone have done a job there.
I Would consider to do a Ring replacement and a valve job. Have not seen the bores yet.
And checking the play in Con rod is OK
I Would try to figure out where the oil went.
But that is just me .There are many ways forward.

 

[Wingedwheel]

Looks like a 2 over piston by the markings but you say it’s 74mm? You said it was blowing oil but was it rings or a bad valve. Theres a lot of things to check before you start throwing parts at it. Are there any markings on the old rings? Can you measure the cylinders?

 

[Timmy hutts]

Just putting it out here as food for thought.
Splitting the crank is a Big Big Big job Maybe .a 5 -6 -- 700 $ US A lot can go Wrong.

Those pistons there looks almost new ..By the few pictures I may be wrong and you can have cleaned them.
But it looks as if someone have done a job there.
I Would consider to do a Ring replacement and a valve job. Have not seen the bores yet.
And checking the play in Con rod is OK
I Would try to figure out where the oil went.
But that is just me .There are many ways forward.

It went from running half decent to smoking and pumping oil through it. Piston on left is untouched. Piston on right I wiped a bit for numbers. The bores look clean to me. No scuffs clean and no ridges that I can tell. If you look at the valves though that’s untouched. It’s burning oil like crazy. Barely got it home.

 

[650Skull]

To install a 447 cam, (with the 447 camsprocket), when converting a 256 crank conrods and pistons to a 447 crank, conrods and pistons, the 256 crank can be retained but the crank sprocket has to be changed to suit the 447 cam sprocket.

That involves splitting the crank.

Pay to check conrod side play and conrod small end for wear before making any decisions. If either of the 2 fail the test, that determines if the bottom end needs to come out.

Cheaper option, if the bottom end and conrods are good, is to onsell the 447 kit and parts and reorder 256 parts

 

[Timmy hutts]

Looks like a 2 over piston by the markings but you say it’s 74mm? You said it was blowing oil but was it rings or a bad valve. Theres a lot of things to check before you start throwing parts at it. Are there any markings on the old rings? Can you measure the cylinders?

Well I basically ordered everything to redo the whole top end. It wasn’t because I had to. it was because I could. Springs, valves, cam, rockers. I was even going to try and port the head to get everything really rolling. I’m no mechanic but I learn quick. Im hoping I can pull it off. We will see though

 

[Timmy hutts]

To install a 447 cam, (with the 447 camsprocket), when converting a 256 crank conrods and pistons to a 447 crank, conrods and pistons, the 256 crank can be retained but the crank sprocket has to be changed to suit the 447 cam sprocket.

That involves splitting the crank.

Pay to check conrod side play and conrod small end for wear before making any decisions. If either of the 2 fail the test, that determines if the bottom end needs to come out.

Cheaper option, if the bottom end and conrods are good, is to onsell the 447 kit and parts and reorder 256 parts

If I was able to find a 447 crank will it interchange easy?

 

[650Skull]

Need to do due diligence before starting or else you end up buying wrong and making mistakes.

Stop where you are and reassess what you have.

Need to learn to to use your the calliper properly or get it recalibrated. There is no way that piston is 44mm especially as it is .5mm oversize.

 

[Jan_P]

As Mr Skull says the con rods needs to be checked I have a senior Mech that helps me ..He is Retired.. grumpy but Knows a lot.

I would put in the spark plugs in the head pour in some fluid I use gasoline but outdoors since it is flammable
Se how much it is leaking.

 

[650Skull]

If I was able to find a 447 crank will it interchange easy?

Not 100% sure. Think so but the 447 crank has the starter gear on it where early XS1/1B doesn't have electric start.