valve lash question

[gravelman]

howdy guys i have a question on valve lash does anyone with the early 70 -73 actually run 006 int and 0012 ext lash .iwas reading the specs and i think thats a little wide myself and wuld probly be real noisy i have been running 004 -and 006 .and the bike performs well with not to much tappet noise so i was wondering if any if u guys where running the wide gap i just dont want to do it any harm my bike is 1972 xs2 any input be welcome thanks joe

 

[gggGary]

Wow, I just set the valves on the 73 I'm working on and just used .025 and .06 because that's the spec I'm used to on the later bikes. Sounded good when i fired it up...... That was about where they were when I checked them also.

 

[5twins]

I think this was a case of Yamaha using the large clearances when the 650 first came out and then realizing they clattered too much and also didn't need to be that big. They speced the big clearances for the first year only and then closed them up to .003" and .006". There was no change in the motor that would warrant the change.

http://i1020.photobucket.com/albums/af327/bmwbobz/Service Data/70-71XS1-XS1BServiceData.jpg

 

[cra-z1]

I use .004 & .006

 

[GreasyC]

On my 71 I ran .003 and .006 because that's what it recommended in the Yamaha manual for it. I experimented with going up a thou or two on each. Going bigger changed the sound and feel a bit. Bit sharper exhaust pops, I think a bit more low rpm torque. Didn't notice any extra tappet noise but it's a real noisy engine to start with so who knows. I went back to doing a bit of a loose slip fit at the stock numbers and never thought about it again.

 

[gravelman]

thanks alot guys i just wanted to get some feed back on the topic i thing i will stay with the tighter clearnce may be 04 06 thanks for ur in put joe