Building an XS1B and wondering if ...?

[Ronnie_D]

Hello Guys:

I am a big fan of this site and read the news every day. Lots of fun.

I am building a 1971 xs1b and trying to collect parts to complete. I know of a 1972 xs2 for sale, rolling parts bike.
The front end is an xs1b and a beauty.
I am just wondering if the cylinder and head (top end mainly) would fit on my xs1b bottom end?

I want to keep the numbers matching on my restore.
l am building an xs1b like this one...


thanks for your input.
Ronnie_D
surviving winters grip...

 

[XSLeo]

I wouldn't pass on the parts bike. Use that engine while you rebuild the 71.
On your 71 I might consider swapping the internals for the later 447 engines, easier to find parts.
Leo

 

[motormike]

Rebuild your stock engine. I rebuilt my 1970 Xs1 with a 73' crank assembly. Early 1970 units used needle bearings for the upper piston pin.. failure was just a matter of time. Mine pack'd up a year after I purchased it. Your stock engine can be rebuilt and keep it stock.. original as possible. The time.. $$$$$ .. will be justified and you'll be a very proud Xs1b owner.

 

[Ronnie_D]

Rebuild your stock engine. I rebuilt my 1970 Xs1 with a 73' crank assembly. Early 1970 units used needle bearings for the upper piston pin.. failure was just a matter of time. Mine pack'd up a year after I purchased it. Your stock engine can be rebuilt and keep it stock.. original as possible. The time.. $$$$$ .. will be justified and you'll be a very proud Xs1b owner.

Thanks to all for the input.
I think I will collect and rebuild with the correct parts for my engine. Perhaps find a 73 crank and do that as well.
I will buy the XS2 because I need the XS1b front end on it.

 

[motormike]

..you shouldn't need the 73' crank on your 71'.. I was told.. that dur'n the production run of 1970 motors... the needle bearing issue was discovered and they went with a standard piston pin bushing with later Xs1 engines. On Xs1 engines... you will need to cut the cam chain.. the slot that the cam chain runs in has a web between the cylinders.... this web'n was also drop'd.. but I'm not sure when. Perhaps other smart'r folks can assist.

 

[Ronnie_D]

thanks motormike

here's the xs2 parts bike

 

[motormike]

..can you provide better photos..of the wheel..both sides.... the legs look like there's a issue. .. the fender lugs are on the outside..?... are you sure it's a Xs2 unit.... with electric start.... the compression release on the LF valve cover...? or.. it's a 71' in 72' colors from a PO....

 

[Ronnie_D]

he says they are 72, 2 engines and frame. I am going on Tuesday to have a look. I am in Calgary and he is in Edmonton.
I hope it is a 71 but I don't think so.

2 other pix I have...

'

 

[Ronnie_D]

I think he just plugged it together quickly to make a roller as he just finished his 71 build.

 

[jussumguy]

It looks to me like it has a drum brake. If it came that way then it's a 70-71 ya?

 

[Ronnie_D]

he said it's a 72 with a 71 front end.

 

[TwoManyXS1Bs]

You'll want to be mindful of the camchain tensioner systems used on these bikes, and avoid any intermixing of different systems.

Here's your homework.

http://www.xs650.com/threads/cam-chain-tensioners.1056/
http://www.xs650.com/threads/top-end-noise.39691/
http://www.xs650.com/threads/excessive-timing-chain-slack.42215/
http://www.xs650.com/threads/xs-engine-fix-up.47242/

 

[jussumguy]

Oops, sorry you're right!

 

[Ronnie_D]

thank you 2m for the info. I think I will do a 71 parts restore on my 71 engine, keeping it factory stock.
I could run the 72 engine to ride her for now.