336° Camshaft.

[Deleted account 111026]

I'm in the process of fitting a 336° camshaft to a 1000cc 'big-valve' motor.
Apparently BMWs instructions are to reduce the fitted valve spring length from about 38mm to 36mm.
I've searched the parts lists for bikes that were listed as having the 336 camshaft as an option and all specify standard valve springs without an additional spacer for below the bottom spring seat.
Also, when measuring the free length of a handful of new valve springs, I've measuered a difference of up to 0.9mm!
I can't believe each BMW dealers would have had a lathe in the corner for turning spacers, so how necessary are they?
As the camshaft is longer duration with only slightly more lift, it should be easier on the valves anyway.
Has anyone else fitted this camshaft and have they encountered any valve related problems?

 

[richie moore]

I have a lot of experiance with these cams , first what do you call a big valve motor. you will have a lot of probs with this cam eg tickover and unless you do a lot of other work the 308 is a better bet. for the extra hp at the top of the rev range you can gain you will get endless coughing and spitting at low rpm. you need to tell me more about your engine and i will tell you what to do for the best result.