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So at 17 weeks to the day after ordering I finally received my Thunderheader PN#1027 for my 90 FXSTC. One problem I have with it is that it comes within 1/4" or less of the brake hose feeding my rear master cylinder from the resevoir. That cylinder won't rotate due to the square hole how it fits in the frame bracket so I ordered some thermo-tec sleeve material, intended for spark plug wires that rest on headers, to wrap around that hose at least for the first couple inches of it. Anyone else run into this problem? Maybe 1/4" is enough air gap that it isn't an issue but it just seems awfully close to me.
Last edited by thsorens; Apr 10, 2026 at 12:46 PM.
I just checked and I have closer to 3/4" of space. I do have is a plugged bung that comes that close to my reservoir and it did cause a problem for me, but heat at the head-pipe would be significantly higher then down below.
I would similarly look for some type of heat shielding material just to be safe - time will tell if this is a real concern.
Last edited by Old Sport; Apr 10, 2026 at 01:07 PM.
Would it be possible to connect a steel line, with a piece of hose just long enough to connect to the master, and bend the steel line away from the ehhaust. Then connect the line to the reservoir with another rubber line? Again I/m just guessing because I don't know what kind of room you have to work with. Good luck.
A lot of folk just wack the pipe where its close and not seen to get a little more clearance. Id look for another solution a heat shield while helpful isnt so great either because your closing the gap and getting less air movement. Heat transfers in multiple ways. Transference being one of them. Radiant another.
Last edited by Rains2much; Apr 20, 2026 at 05:25 AM.
A lot of folk just wack the pipe where its close and not seen to get a little more clearance. Id look for another solution a heat shield while helpful isnt so great either because your closing the gap and getting less air movement. Heat transfers in multiple ways. Transference being one of them. Radiant another.
I thought about denting the pipe but not crazy about the idea. I think I'll grind the corners off the square part of the master cylinder so I can twist it away from the pipe a bit.
I thought about denting the pipe but not crazy about the idea. I think I'll grind the corners off the square part of the master cylinder so I can twist it away from the pipe a bit.
take everything I say, with a grain of salt. Im gonna tiptoe across the eggshells because its well known that I absolutely hate with a burning heat of 1000 Suns the thunder header. I realize others think its a great choice and like it. So with that disclaimer in place
Let me repeat back to you, the words that I read coming from you.
Youre thinking about grinding away the OEM part that was absolutely engineered, tested over and over again, to meet all kinds of regulations and perform stopping power, that can save your life being a brake, and youre choosing to grind near the seal, and compromise its integrity, for the sake of the bling of the blunder header.
Man, if I just spent close to two grand with tax and shipping and waited all the time for that pipe, I wouldnt want to relieve, swing at it either. I understand. Its bling, its kind of status, in your opinion it looks cool, and sounds good. I do understand. But take a serious thought and step back before you grind away your master cylinder. You know the piece that was engineered to be there in the first place, that stops you so that you dont die. Or whack the blunder header where nobodys going to see and give yourself a little clearance.
I think if I were in your shoes, I would look for a different kind of master cylinder, or maybe a way to slightly relocate it? Move the OEM bracket that holds the master cylinder?
I would dare to say that when push comes to shove, if you really evaluate at the end of the day, the advice I give on the Forum is not popular but Im usually not wrong. But its usually never the advice anyone wants to hear.
Last edited by Rains2much; Apr 20, 2026 at 11:03 AM.
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finally got my Thunderheader but......
