So I have to wonder what effect a little squished into the exhaust port header gasket would have on a stock stage 1 bike. Everyone seems more concerned with a tiny bit of gasket material squeezing into the exhaust head port rather than they are with an exhaust leak from a poor sealing gasket. From what I can tell after installing my new exhaust with stock gaskets, even at multiple times of torquing down and re torquing the flange nuts, 120 inch pounds isn't much. What is suppose to be the ill effects? The way the header pipes are designed, I don't think its possible to squeeze enough gasket material into the port to do a thing? If its tightened to that point (over tightened), you'd probably end up replacing the gasket because of a leak.

 

Getting a good seal is no less important to me, the gasket squishing into the port is just an additional concern; the effect is a restriction in your exhaust tract, which negatively impacts performance. I don't particularly promote a specific gasket, but I do share the experience I had with the OEM's and the SEs, in case others have simmilar issues, it is a potential option to try to resolve problems. There is nothing wrong with OEM exhaust gaskets per se, they just did not work for my application. Many people swear by them and simply won't use anything else, I use whatever works. If "you don't think it is possible to squeeze enough material into the port to do a thing", consider this example of port cross section area reduction with only 1mm squished into the port: original 39mm port or 11.94 square cm vs. 37mm or 10.74 square cm. That is just about a 11% restriction, factor the perfomance loss however you like, it's still a loss. I actually had more than 1 mm in the port, but I had a great seal. Best explanation I can offer.

 

I appreciate the explanation. I asked because I did not know. I also am a little concerned because when I installed my new exhaust, I used stock gaskets and I torqued to the recommended 120 inch pound final torque. I stll have not been able to get off of my road for a ride, but while making some other mods I have run the bike in the garage. So when I did go back and check the flange nuts, I eneded up torquing again, and it semed like more than it should have been. Hence another reason for my question. I was also offering my observation based on what I saw. I welcomed your opinion Thanks.

 

I never re-torque the flange nuts hot, and I only do it once to the lower value of 100 in/lbs, after a complete cool down. Those OEM tapered gaskets are very soft, if you torqued them warm, used antisieze or some kind of lubricant on the threads, or just retorqued them too many times, you may have tightened them too much.

 

I didn't use anything on the threads. I also ony retorqued once, however the bike had run for about 3 or 4 minutes prior but had been allowed to cool some. Live and learn. So how will I be able to tell if they are over torqued?

 

I'm not sure you are over-torqued. The recommended 100-120 in/lb is based on the soft gasket application, not the fastener's limit. Over-tightened is a little misleading, I should have said over-compressing the gasket. The gasket will always "give", to a point. In order to excced the basic torque limits for the flange stud and nut, you would have to tighten them so much that the gasket would completely compress and squish out to the point you that you have metal on metal contact between the pipe primary flange and the port. You will have gasket material squishing into into the port long before that point. This should also help to illustrate the concern for gasket material squished into the port when installing an exhaust. I mentioned the anti-seize and hot re-torque, because they are the most common cause of "over-compressing" the gaskets. Actually the manual proceedures do not include re-torquing, it is just a generic exhaust practice that a lot of folks choose to follow. For your specific situation and concerns, I would pull the exhaust again, inspect the gasket condition, if they are not squished into the ports, wire brush the flange studs clean, get new flange nuts, re-install the exhaust followng the manual proceedures and tighten to the lower or middle value of the quoted range. Run it and check for leaks, if it leaks let it cool down completely and torque again to the higher quoted value, if it still leaks, replace the gaskets with new ones , or just go ahead and replace the gaskets now and forget about it.

 

Thanks for the advice. Since this is a brand new exhaust install and as I mentioned, I did not exceed 120 inch pounds, on either of the tourquing procedures and also looking at the flange in relation to the head distance (even and still a decent distance apart), I think I'm going to at least run the bike down the road before I make the decision to pull the entire touring exhaust off again on a whim? I was much more careful than most. At this point the muddy gravel road I live on is still impassable by motorcycle after a long cold winter, so I probably won't get my first road ride in until Merorial day if I am lucky! In any event, I think I'd be more pissed at myself if while removing and reinstalling the new exhaust, I managed to scratch and or otherwise damage the new pipe, only to find that the gaskets and torque were just fine. I do thank you for your knowleagable input. Thanks Again, Rick

 

Sounds like a good plan, run it and see what you got first. Sorry to hear you're mudded in, hope your road dries up soon.