Topic: Chronic problem with drive chain slack.

[seanbarney41]

Of course I had the opposite problem, but here's some interesting reading for you about the offset front sprocket and wider swing arm on the 77/78 bikes. I did a LOT of research into this topic and, as others have noted, you may not have what you think you have motor/frame-wise.

http://forums.sohc4.net/index.php?topic=103649.0

 It has the chain oiler and the carb boots are a different size. 

yeah, that sounds like a 'pre 77' motor...could be the previous owner already corrected the driveline offset mis-match

[Ira]

Update on this:  Everyone who suggested a chain line issue was right.  Even though it looked ok from the focal length of my camera phone, it was obviously wrong from five feet back, with the bike on a lift.  In fact, when I took the "new" chain off it was extremely worn laterally.  It could almost be flexed into a letter "C"!

So- I swapped my '77 carrier for a '75 sprocket carrier and the correct axle spacers.  This was possibly due to the expertise and generosity of a local ChiVinMoto member and sohc4 expert- if you live in Chicago, you know who I'm talking about!  He knew exactly what to do had the right parts on hand.

Now I have a correct '75 chain line, proper wheel spacing and a new, stronger, standard chain.

[Tugboat]

Well done! Glad to hear it all worked out for ya.

[bollingball]

Yep 10mm makes a lot of difference.
Ken

[Holubs]

My brother was the original owner of my F1.  He is a doctor, and didn't realize that you had to adjust on BOTH sides of the rear wheel equally when you tightened the chain!  He only tightened the chain side adjuster to adjust the chain.  He totaled the bike after 5000 miles, which wasn't due to the chain adjustment technique.  When I bought the F1 from his insurance company the original chain could be bent sideways into a "C".

Holubs