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Discussion Starter · #1 ·
I have a question. I'll try to keep it as short as possible, but I tend to get long-winded, so please bear with me...

I'm replacing the rearsets on my bike. Last year I put a set of Bohemian Racing ones on, and the anodizing faded. I got a new set from them for nothing, so I'm just redoing what I already did. I'm having the same problem I did last year with the feed line from the reservoir to the MC. The rearsets move the MC up and back and cause the feed line to kink. Last year I somehow managed to get it to work with the stock line, but it was a PITA.

I bought some Tygon tubing in hopes it would work better, but it's not, so I am thinking of removing the reservoir and just using the Tygon as the reservoir - like the cool guys do! ;D

I was trying to come up with a solution for capping the line, and this morning I went to Lowe's and found some brass fittings that should work, except I don't know if there is the potential for nasty chemical reactions between the brake fluid and the brass. 1st question: Would it be okay to plug the line with a brass fitting.

Brake reservoirs have a a rubber diaphragm in them that follows the fluid down and prevents a vapor lock that would stop the fluid from flowing to the calipers as the pads wear. I obviously wouldn't have anything like that in my planned solution. 2nd question: Should I worry about this, or is it a non-issue?

A poster on another forum said he just caps the line with a bolt, and that if venting is desired, a small hole could be drilled through the center of the bolt. If I decide to drill a hole, that would eliminate question 2, but create more questions about contaminants having an easy entry into the reservoir and fluid. I bought two pieces of brass. One is fluted on one side for inserting in the tube and threaded on the other. The other is a threaded cap. It would be very easy to drill a small hole in the cap to vent it. I'm going to position the cap under the right frame cover, so I'm not too worried about dirt and other bits getting in there, but am worried about the fluid attracting water from the very humid air we have in NOVA. So, I guess question 3 is to drill or not to drill. Unless I can be convinced otherwise, I'm leaning towards not drilling.

My final question regards getting the fluid into the system. I have a Mityvac, and all the assorted tubing, but am not looking forward to the back and forth of getting a small volume of fluid into a very small (5/16") opening without spilling it all over my bike, sucking a little into the system, refilling, sucking, repeat, repeat, repeat. However, if I replace the vacuum pump with an air pump, I should be able to force the fluid into the bleeder, through the caliper, MC, and up into the tube/reservoir. If this works, I could even cap the reservoir and force just a bit more fluid in to pressurize the air above it in the tube, which would at least partially eliminate my feared vapor lock scenario. Question 4 (in two parts): Has anyone filled their system "backwards?" Does it work?

So, that's it. If you made it to the end of this post without falling asleep or being distracted by something shiny, I congratulate you and await your responses.

Thanks in advance.
 

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I was trying to come up with a solution for capping the line, and this morning I went to Lowe's and found some brass fittings that should work, except I don't know if there is the potential for nasty chemical reactions between the brake fluid and the brass. 1st question: Would it be okay to plug the line with a brass fitting.

Brake reservoirs have a a rubber diaphragm in them that follows the fluid down and prevents a vapor lock that would stop the fluid from flowing to the calipers as the pads wear. I obviously wouldn't have anything like that in my planned solution. 2nd question: Should I worry about this, or is it a non-issue?

A poster on another forum said he just caps the line with a bolt, and that if venting is desired, a small hole could be drilled through the center of the bolt. If I decide to drill a hole, that would eliminate question 2, but create more questions about contaminants having an easy entry into the reservoir and fluid.
This might be easier. Honda designed a kit to do exactly what you are trying to do. If you just want the plug, the part number is listed as well. At least you wouldn't have to worry about it not working.

http://tyga-performance.com/site/product_info.php?products_id=459

I guess it comes that way from the factory on some of the HRC GP bikes. I dunno. Never owned one.
 

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Instead of brass fitting I would try to find a nylon bolt in the hardware section with the right diameter and cut it short to make a plug.

The tubing is somewhat flexible so I'm pretty sure as long as you make the tube long enough to leave some air in it you shouldn't have a problem with vapor lock.

I have seen people use a surynge to "back fill" a brake system. It would be a little harder to keep the lines on since you don't have the suction of the vacuum holding them on for you, I'm sure going slowly would be key.

 

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I doubt you'll have problems with brass corrosion from the brake fluid. Brake fluid is composed of organic compounds and solvents so it's hell on plastic and paint but it doesn't attack metal.

I would also go with not drilling. The seal from your plug at the top probably isn't going to be tight enough to allow a vapor lock and as you mentioned you're talking about a very small volume anyway.
 

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I would also go with not drilling. The seal from your plug at the top probably isn't going to be tight enough to allow a vapor lock and as you mentioned you're talking about a very small volume anyway.
If you drill, you could angle a 1/16" bit so it exits below the top thread. This would keep the head and shoulder of the bolt from being an airtight seal. It would also let you "tighten" the bolt slowly to purge air that might seep in, simply by cutting the top of the tubing without removing it.
 

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Discussion Starter · #7 ·
Thanks for all the input. The brass fitting appears to fit into the tubing very solidly - so much so that I didn't push it past the first ridge on the fitting for fear of not being able to get it back out without cutting the tubing off it. I've decided to fill the fluid conventionally. The turkey baster also fits well into the tubing, so I can use that as a funnel. I just need to secure it in an upright position, and I have plenty of painter's tape to slay that dragon.

Tonight I'm going to attack this, and let anyone interested know how it all works out.
 

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Interested on how this turns out. I have a friend who has a race/track bike and he used this same idea because he crashed and didn't want to replace the res. But he did mention that he keeps an eye on it and checks it before and after every race/trackday and looks for leaks, damage or wear. Its something that is constantly on his mind.
 

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Discussion Starter · #9 ·
I really don't use my rear brake much. Hell, the whole thing could fall off, and I probably wouldn't even notice it until I was stopped at a traffic light on a incline. However, I do agree this will require me to increase my inspections/maintenance of it over what it is now - which is basically non-existent beyond being sure that the pedal activates the brake light, so I pass my yearly inspection. ;D
 

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I was speaking to a trackday coach about the use of the rear brake. His first question to me was what group I ride in. When I said "yellow" intermiediate he said stay off it. He says that at the moment I wouldn't gain much from it and it would be more of an issue to learn it correctly and may hinder me from learning and mastering other skills that I need right now. He also mentioned that he actually introduces air into the system to make it a softer brake, so that it doesn't bring the wheel to completely stop. He does this on purpose since he only uses it to settle the bike going over hills and into and out of turns to help his line if he is off line after passing or something. He said to use it correctly your sensitivity to changes in pitch forward and aft and from side to side has to be very high.
 

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Discussion Starter · #11 ·
I will just drag it a little sometimes when slowing just to try to retain some sort of feel for it, but when I need to brake, I'm just on the front.
 

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Discussion Starter · #12 ·
Well, here is how it turned out:

 

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I have had mine as only a tube for some time now, I never use my rear brack on the track though. I have the tube much shorter, maybe 4"-5".

I would change the clamps you have to this style clamp for better security

I have found that the PVC tubing may cloud a little over time, but for the cost of tubing it is worth just changing it out and doing a bleed every now and then, maybe once a year.
 

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Discussion Starter · #15 ·
It's 5/16" ID Tygon 2075. I got it from KurveyGirl. It's the second of the two options here.

I'm sure you can find it at some local suppliers, but I didn't have any luck a AutoZone. NAPA or Pep Boys might have it. :dontknow:

I think I might reposition the cap to be more upright. I don't like it laying on it's side like it is.
 

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Discussion Starter · #17 ·
That is a definite possibility. I'd just have to drop the fluid level a bit. I'd also need to figure out how to secure it - the brass fitting is nice, but it's a fair amount of weight at the top of a not very rigid tube. Don't want it flopping about under there. ;D
 

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Discussion Starter · #20 ·
The one you see on the right is just for symmetry. There is also one on the left and they are TechSpec, but I didn't cut them. Short story long: With the stock rearsets, either the button snap or zipper pull on the left leg of my Aerostich suite was wearing the finish off the bottom portion of the frame. I decided against trying to repaint it, because it just would have worn off again.

I contacted TechSpec, and they said they could cut any shape I wanted (for a price), as long as I provided them a template. I made templates out of a file folder, sent them off, and BOOM! Custom Frame Protectors. The flash on the camera makes it look a little grayer than it is. Here's a picture of the one on the left, that is actually covering the "damage." It also looks grayer in this shot than it really is.

 
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