Cam Chain and Valve spring Help

cscarroll · Full Member Joined: Oct 08, 2006 Posts: 112

Fellas,

About ready to build my '74 motor back up. Wanted to check a couple things.

I saw on mikesXS he sells a new front cam chain guide bar. Do I need to replace the rear portion as well? Mine show very little wear, I'm just worried with the plastic being so old, things might get brittle.

Also, I measured my valve springs (inners and outers) and they are bit undersized from what the shop manual lists for a height (.5 mm or less). Does anyone have an idea as to what the limit is before they should be replaced? My factory shop manual doesn't list a wear limit for these.

Thanks in advance. Pics to come once things get moving. Pretty excited to see this motor run as I've punched it out to 680cc.

-C

Finksies

I just replace the front guide bar aswells, and left the tensioner since it looked fine. Make sure to replace the valve seals, cheap insurance. Not sure about the springs. I just put mine back in. There is a top and bottom to the springs if u didnt know, cause i didnt and had to take the springs back apart. Good luck.

cscarroll · Full Member Joined: Oct 08, 2006 Posts: 112

Fink.

Thanks for the 2 cents. I do have new valve seals so should be good there.

grizld1

The factory manual specifies 2 mm. short of original length as the service limit. Your springs are fine.

cscarroll · Full Member Joined: Oct 08, 2006 Posts: 112

Griz,

That's what had me confused. My manual did not list the 2 mm short as the service limit.

Wish those engineers could make up their mind...

Thanks.

-C

grizld1

'78 edition, Engine section, p. 24 (all the 447 valves gear's the same). The tech writers are probably more to blame than the engineers--maybe enough guys yelled about that omission to get it corrected in later manuals!

What Happened to 650rider.com?

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