Typically, the response to sealing the exhaust is to use the orange RTV (return to vendor?) sealant or machine o-rings. My frustration began after attempting to seal the exhaust, on the recommendation of many others, with the orange poo. Obviously, this did not work, and it blew out in every possible location where it was applied immediately. The advise I was given was to try again, make sure everything is clean and you allow it to set. This was repeated more than once with no success.
I then spent time chasing a machinist to machine some grooves in to the flange. However, chasing down o-rings to meet the size specifications was unsuccessful. The machinist was very apprehyensive of machining too far in to the wall of the flange and weakening it so we looked in to alternate methods of creating a seal when we both came up with this idea.
It is my hope that this solves not only my problem, but is able to help others seal their exhausts to help get a few extra horses out of their bikes and, most importantly, keep those TYGA SS pipes and fairings as shiny as the day they were bought.
Before you begin you should be hoping you won’t have to remove the exhausts for quite some time if this is successful. So take this opportunity to clean the carbon out your chambers and adjust the power valves using the HRC method, as the method of lining up the notches is not very accurate.
Firstly, you will need two o-rings to make a seal between the pipes and the flanges. I found the vitron o-rings from a ’98 KTM 125/200 fit perfectly (part number 0770420015). You will require two exhaust gaskets, some high temperature sealant (avoid using the orange stuff, as it seems to make things leak more). I am using 750F rated grey gunk from here: http://mochem.com. Some PTFE (teflon) tape (I heard moose sell this, though I am just using non specific plumbers tape).
For gaskets, I tried using exhaust crush gaskets that I picked up from an exhaust specialist. It worked fine on the top cylinder, however I was not able to get the pipe to bolt up to the mid mount on the front cylinder pipe. For this pipe I cut myself a silicone ‘gasket’ that I made out of a silicon bake tray. It is nice and soft and is able to withstand high temperatures. We will see how they both hold out!
This doesn’t need saying, but I’ll say it anyway. Clean everything, clean it twice, no, thrice. I am using brake cleaner to clean the parts. Make sure all the carbon is removed from the contact surfaces too.
Check to make sure your exhaust rubber mounts are good. They do have a fair amount of play, I replaced one of mine but I am sure it would have been fine as it were. If they’re too sloppy and/or perished, replace them. This should eliminate movement further.
Place the collar on the pipe (do this as soon as you can, as it’s annoying getting everything together and realising you’ve forgotten the collar!). Wrap a good amount of PTFE tape around the outside of one of the flanges, checking fit as you go till it’s a nice tight fit inside the pipe. Once you are satisfied, install the o-ring as shown in to the pipe and insert the PTFE wrapped flange in to the end of the pipe. Start by loosely mounting the exhaust to get the right angle and check the fit. The o-ring should compress and seal under the tension of the springs, and the PTFE should inhibit movement to some extent and add an extra seal.
Once you are satisfied it will go together, apply sealant to both the clean exhaust port where the flange mounts, and the outside rim of the flange. Insert the gasket in between the two surfaces and tighten the nuts on to the collar, compressing the gasket somewhat.
Install the springs on to the pipe, and finish by tightening the bolts on the collar, further compressing the crush gasket, and the rear mounting bolt.
Repeat the same procedure for the other pipe. If you have two pipes on the one side, running a clamp to hold the end cans together (sold by TYGA) can further reduce the movement in the pipes. However, running the o-rings and gaskets has reduced movement by a large margin for me, I may not run the exhaust clamp this time and see how it goes.
Remeber to leave the gasket gunk to cure. Supposedly the grey gunk I am using does not require curing, however it is probably best to leave it overnight.
CAUTION: Vitron has a temperature range up to 220C. Much higher temperatures it can burn and disintegrate, creating hydrogen fluoride. When in contact with water, it becomes hydrofluoric acid, which is highly toxic and merely touching it can result in an acid burn. It is highly possible you will not feel this burn, and left untreated can lead to cardiac arrest and/or the necessity for amputation. Fortunately it is treatable, so if you suspect you’ve come in contact with burnt vitron, seek medical assistance. Remember, wear gloves.
Coming soon ... first ride, was it successful?
_________________
MC21 Honda NSR250. TYGA 300 conversion.
|
