Top end rebuild

[Roy]

So I have a 1971 xs1-b 650 with unknown miles. No history from the previous owner, and no speedometer on the bike when I bought it. I have no idea about the actual mileage, but I'm guessing a lot. The cam chain seems to be stretched out enough that I can't set the ignition timing correctly. I had to grind the points backing plate a little just to get the timing close. On occasion the bike gives off a big cloud of smoke when I first start it. Not very often, but occasionally. Oh, and it's burning oil. With all that being said, I think it needs to have the top end rebuild. Do valve guides ever need replacing, or just the seals? What should I plan on money wise for this project provided I do all of the work? Thanks for all of your help.

 

[Its been a long time]

So I have a 1971 xs1-b 650 with unknown miles. No history from the previous owner, and no speedometer on the bike when I bought it. I have no idea about the actual mileage, but I'm guessing a lot. The cam chain seems to be stretched out enough that I can't set the ignition timing correctly. I had to grind the points backing plate a little just to get the timing close. On occasion the bike gives off a big cloud of smoke when I first start it. Not very often, but occasionally. Oh, and it's burning oil. With all that being said, I think it needs to have the top end rebuild. Do valve guides ever need replacing, or just the seals? What should I plan on money wise for this project provided I do all of the work? Thanks for all of your help.

Yes they do wear. You won't know for sure until you take the top end off.

 

[Jan_P]

A compression test would be a good thing first.
A Danish gentleman Heinz here on the forum need to replace valve guides.
Possibly new rings or more --- difficult to say the grand total. Before

 

[Vincenthdfan]

So I have a 1971 xs1-b 650 with unknown miles. No history from the previous owner, and no speedometer on the bike when I bought it. I have no idea about the actual mileage, but I'm guessing a lot. The cam chain seems to be stretched out enough that I can't set the ignition timing correctly. I had to grind the points backing plate a little just to get the timing close. On occasion the bike gives off a big cloud of smoke when I first start it. Not very often, but occasionally. Oh, and it's burning oil. With all that being said, I think it needs to have the top end rebuild. Do valve guides ever need replacing, or just the seals? What should I plan on money wise for this project provided I do all of the work? Thanks for all of your help.

It's certainly worth the effort and time...its gorgeous.