Hitchcocks Forum

Hi all

As mentioned in a previous post I have just installed the tuned cylinder head from our host. Everything is running smooth now and it is about time to re-torque the head bolts. But how many kilometers should I ride before I do so? I have used the composite gasket with no sealant.

best whishes
Jacob

My understanding is that you should check the head bolts once the bike has been run up to temperature, or after a short run. If you don't you run the risk of blowing the head gasket. You can always check it again in a few weeks.
If you have an alloy barrel don't over do the nut on the pushrod side as they are notorious for pulling out and only really seal the push rod tube. The manual shows the same torque for this as the head bolts, but I don't trust it.

I was told (by someone who really ought to know) that the composite gaskets don't need retorquing. I didn't and I've had no problems.

Re torquing after pulling the head , the studs and nuts flex on the first heat , things will shift , only takes 1/2 an hour .

Hi Jacob. It certainly won't hurt re-torquing the head nuts. Perhaps any time when it's convenient to whip the tank off after riding it a hundred miles or so. I always find that nuts often suffer from "stiction" so to avoid erroneous torqeing, I would loosen the nuts a half turn each loosening them in the diagonal sequence as you would tighten them, then re-torque them all sytematically. Out of interest you might which to mark the nuts as a reference to see if the re-torque does indeed give you a new tighter final nut position. Peace of mind will be worth the small effort, leaving you fresh to worry about other potential problems

CORRECTION: Out of interest you might "WISH" to mark the nuts etc. etc.

Thanks to all of you for a quick response.

At this time I have been running 40 km in total during two rides. The engine have reached maximum temperature, so all settings in bolts and studs should have taken place. Compression has not been an issue, but I believe a re-torque would not hurt, so this is what i will do. Loosening the bolts a bit first then tightening to correct torque value.

all the best
Jacob

No point backing hem off, just check the torque.

I have to disagree John M. A nut or bolt becomes locked by a sort of "stiction" after it has been allowed to settle for a while. If a nut is attempted to be turned an extra amount from its already tight state it will often trip the torque wrench over the limiter before any tightening is achieved even if the actual stretch tension on the bolt/stud is below what is recommended. So by attempting to check the torque as you suggest can be result in under-torqueing. By overcoming the stiction by loosening first, one can re-apply the tension smoothly and reasonably accurately up to the set torque figure, this second application of pressure is usually more accurate and long lasting as the gasket has settled and fully compressed after being heat cycled. A quarter to half turn back is sufficient. Obviously if the nuts/bolts have become very loose, then the stiction will be naturally overcome just by adding more torque and will not require the back turn, but if the torque wrench fails to move the nut at all, then the back turn is required, as one cannot know if the thread is tight or just stiff.

Les....stiction????? If you slacken the nuts then you are back to square one when you retighten. Simply apply a torque wrench and tighten to the correct torque setting. If there is such a thing as "stiction" (which I believe has no engineering foundation) then it will not have taken hold after such a low mileage/kilometerage but expansion and vibration, added to the explosive effects of the bang juice may have caused the torque settings to have become reduced, and that is all you are trying to correct.