Specs are: .006 Intake - .012 Exhaust

2 of my Intakes are .005

1 of my Exhausts is .011

The rest are all perfect.


Would you take the time to get them perfect, or leave them?

The bike has like 34k miles on it


James

 

I wouldn't. Been there, didn't.

 

Lol

 

Anyone else?

Any truth to someone quoting Hawk: set them all to the loose side of the tolerance to get more mid range torque?

James

 

If your confident that the measurement that you have taken is accurate, as you know, are just at the spec limit. The clearance shrinks with wear. Are you thinking of opening the in spec valves?
I would, because of my ocd, make them all the same one direction or the other. What else have you got to do when it's too cold to ride?
Wouldn't a bigger gap retard the valve timing? and if so does .001mm really make any difference in torque curve?
Curious as well.

 

What else? I'm powdercoating, polishing, changing rear brake master cylinders, changing to stainless fasteners, removing thermostat housing, changing coolant tanks, removing carb heater lines.... I'm not really that busy....

LOL

I'd like to know more about putting them all to the loose end of the spec....

James

 

I'd leave it as is.

 

A good resource to understand valve timing and changes in the power curve is A. Graham Bell's '4 Stroke Performance Tuning'.

 

Your intakes are too tight and will only get tighter with use. Change them both out for the next thinner shim than is in there now.

 

That's a bit vague, since i gave two different intake measurements. Which measurement are you saying is "too tight"?

Why did you only mention the intakes?

James

 

I'd be more worried about tight exhaust valves.

 

You said you had 2 x intakes at 0.005", that makes them the same not different.
The exhaust is 0.011".
Each of these measurements are 0.001" under what they are supposed to be which is 0.006". This does fit within the tolerance of + or - 0.001" just. But seeing as you are this far in I would change the shims.
The shims go up in sizes of 0.025mm which equates to 0.001" or 0.0009" to be precise. So you would have the option of going down by either one or two shim sizes. One size down would make the intakes 0.006" and the exhaust 0.012". Two sizes down would make for 0.007" for the intakes and 0.013" for the exhaust which would mean you would not then have to change the shims for a long time.

 

Oh i realize what happened, i said two intakes are .005, and the rest are perfect (meanijg .006, so in my mind i gave two different measurements.

Anyone know more info about hawk's theory of setting them all on the loose side of the spec to get more power in a certain rpm range?

Thanks for the comments so far!
James

 

Technically less overlap on the valves will give more power in the midrange. How much and at what rpm is open to conjecture.

 

I faced having one valve .001 too tight when I last did a check. I took the cam out and changed the shim to get the correct tolerance. If you are not going to do something about it, why bother to check? Just keep riding until something fails or you loose compression.
While you're at it, quit changing your oil. That's just preventative maintenance too.
All the other things your are doing require effort but they don't help the longevity of your bike. Get that cam out!

 

OK, if you say that we have to, I guess that's the last word. I hope.

 

It was just a simple question...

James