Master cylinder kit problem

[Rev.Rick]

Hey Y'all I got a question. I'm in the process of replacing my brake lines and rebuilding the front master cylinder. I my mastercylinder kit came today but there's a problem. The plunger is to big. I have a 1980 XS1100 special. The kit for that calls for a 17mm, however it obvious that this is not the correct mastercylinder for this bike. I know this isn't much to go on but I do believe this to be a Yamaha mastercylinder. However it has a flat bowl on it instead of the slanted one that was on my 850 special (due to the funky special handle bars). I know that the standard 850's have a flat bowl. Is there a difference between the mastercylinders on a 1100special and a standard. the only identifing numbers I see on this one is Nissin 14. the cap and bowl are indentical to the special other. the difference is the size of the plunger. please help if y'all can. I want to get the right parts and be riding! Rick

[bikerphil]

The Yamaha front MC rebuild kit (P/N 1J3-W0041-20-00) is listed for both the 80 Special and 80 Standard. That leads me to believe there is no difference in the units other than the slanted cup. Check with your supplier, they might have shipped you the wrong kit.

Source: http://www.yamaha-motor.com/sport/my...starthere.aspx

[CatatonicBug]

The OEM master cylinders should be the same. Can you post a picture of the MC you have, so we might be able to identify it? It's not uncommon for folks to change out the old MCs for a newer one when parts are hard to come by. I had to do that with my rear MC, as the rebuild kits for the '81 MNS are not available anywhere.

[Rev.Rick]

Here's my atempt at posting some pics of the master cylinder




IMG]http://i953.photobucket.com/albums/ae14/lordservant1014/mastercylinder002.jpg[/IMG]

IMG]http://i953.photobucket.com/albums/ae14/lordservant1014/mastercylinder001.jpg[/IMG]

[Rev.Rick]

It only got one hers another

[Rev.Rick]

Got one more



Sorry I didn't get them all in one post. Anyway it certainly looks like a Yamaha MC but instead of the 17mm plunger they sent me in the rebuild kit, this mc has a 14mm? plunger

[CatatonicBug]

That is definitely NOT an XS master cylinder. The lids on the XS ones are perfect rectangles, not a trapezoid like that.

[Incubus]

The master on my XS11 is marked Nissan 11/16. I'm thinking your PO used a different master. Many bikes use a 14mm plunger, including vintage Honda CB750s (SOHC 1969 to 78). The ones I know of are all single disk systems. I wouldn't think that would be a large enough barrel on the master to properly operate a dual disk braking system. But I am certainly no expert.

Patrick

[Larrym]

Trape-ZoidBerg (Futurama...)

That is definitely NOT an XS master cylinder. The lids on the XS ones are perfect rectangles, not a trapezoid like that.

The one on my special:

.........................

[CatatonicBug]

The one on my special:

.........................

I stand corrected.

This is from an SF, and it looks very much like Rick's:



But this is what's on my LH:





I didn't realize they were so different. Of course, I should have realized the fact that the LH front only operates the right front caliper, while all the others do both fronts.

Apparently, though they all seem to look the same from a distance, the Standards all have the same MC part number (1J3-25850-23-00), and the Specials have one of their own (3J6-25850-00-00), except the SF has it's own (2G2-25850-01-00), and the LH (4H7-25850-01-00). I had no idea!

[DiverRay]

The 14 on the MC is the bore diameter. It is NOT a stock unit for the '79 or '80 Special. You have a NON OEM MC on the bike. I would look into getting a MC with a larger bore, or try to find out what that came off. My guess is a 400 to 650 Yamaha.

[Rev.Rick]

Thanks to all for your help. I know this master cylinder was different from the one on my xs850 special. I ran into the same problem with it when I changed the special handle bars out for superbike bars. The MC for my special set at quite an angle on the straighter superbike bars. This made it a pain to fill the reservoir without spilling the fluid. The 850 standards had a different MC that bolted on the front side of the bars instead of on top, so it set level when placed on the superbike bars. I have now put superbike bars on my XS1100 special so I think I need to get a MC that bolts on the front of the bars. I suppose the MC for the standard XS1100 would work.

[DiverRay]

PNM, IIRC, s who I bought a replacement MC from. It went on a standard, and works great! It was about $80, I think.

[Rev.Rick]

I,ve got this kit I just bought for the larger bore MC. I got a great deal from georgefix on it but it still was $30. I can't afford to lose that money right now, so I'm going to try and find a used MC off a stardard xs and rebuild it. Wife is way past being over me spending money on this thing. Not to whine because it's too late now, but I gave $1200 cash plus a restored XS850 for this bike. I bought the 850 for $1000 and probably put 10 to 15 hundred into it just last winter. I wanted what I wanted and looks like I didn't let my better judgment rule when I made this deal. This 1100 has only 800 miles on a completely rebuilt engine, near prefect stock exhaust, great tires, so far no electrical issues. but hey it shouldn't have for the deal I made. I should have checked it out better but like I said I had love in my eyes (love can be blind). She was kinda ill over me making such a deal after I spent so much time and money on the 850. She doesn't understand why I had to have an xs1100 (I do) then to keep running into issues which cost a little here and there is put her over the top. She told me yesterday I should just sell it and get something else (Whatttttt!). Too much into it now to do that . Did I mention I'm not going to whine?

[bikerphil]

so I'm going to try and find a used MC off a stardard xs

Send a PM to member Andreas, he'll probably have one for you.