Front brake Master Cylinders


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Lebanon NY
I have a copy of a list of axle sizes used on bikes. I think I've seen one for front forks sizes.
Has any one ever compiled a list like that for other things?
Such as bore diameters of front brake master cylinders?
I was wondering because I need a new mater cylinder for the 81. I will use a single disc brake.
I like using Yamaha's MC's. I like the way the lever adjusts and looks right. Others the levers won't match the clutch lever.
I have a saved search on Ebay for used Yamaha MC's and there are over 2600 items. None tell me the bore size.
If there was a list that told the bore sizes then I could narrow the search.
There are a lot of new after market sets that have the MC and clutch perch with matching adjustable levers. Some don't tell the bore size, the ones that do sat 12.7 mm.
They come in a lot of colors.
Others on here have spoken about using MC's from other Yamaha's. I can't seem to find these references by searching the forum. If any has used others could you tell me what models and years worked.
Yamaha TTR225 2001-2004
Yamaha TTR250 1999-2006
Yamaha TW200 Trailway 2000-2013
Yamaha XT225 2001-2007
you can use the stock lever, mirror, and brake light switch on these. They are a small bore, 10mm IIRC, But with a stainless line I like them. Ran one on resto for years. The banjo is on the front not the end like the XS650 MC
Thanks for your list gggGary. I'll narrow my search to them to get one for a single disc set up.
Those are 11mm MC's. I have one from a TTR225 on my '78 now. I quite like the better and more progressive feel but am not crazy about all the extra lever freeplay, but I'm growing used to it, lol. I have another MC with a 1/2" (12.7mm) bore that I'm going to try on my other 650. This size is about midway between the stock 14mm and the 11mm. I'm hoping it will be a good compromise, better feel than the stock 14mm but less lever travel than the 11mm. This MC came off a Yamaha Vision.

What I do to find out what bikes to search from is look up a MC I know is the size I want on Partzilla, then check out it's rebuild kit to get a list of other bikes that have that size MC. Here's the listing for the Vision rebuild kit. At around $63, I won't be buying one anytime soon lol, but luckily Banggood has 1/2" MC rebuild kits for less than $2 each .....

Something to keep in mind is that many of these MC's from the cruiser models like the Virago or V-Star are angled like the 650 Special unit. You may not want that. That's why I specifically searched out one from a standard style bike.
5twins, searching like that is a good idea. I just don't know what bore size other bikes use.
I'm using lower flatter bars on my bikes. On the 83 I have a set of bars off one of my Baja mini bikes, I still have the stock bars. I would like to sell that 81. I keep the bars to go with it. Perhaps the new owner will like them.

The size is usually stamped on the MC. If the seller provides the right pics, you can usually spot it. Here's the 11mm one on my '78. You can clearly see the "11" stamped on it .....

I was aware that most M/C's are marked with the size on them. Seems odd that some metric M/C's use an SAE size marking.
I'll have to look closer at the pics to see if I can make out the numbers.
Well, I ordered some brake parts.
On the bikes where I took off high bars and put on lower bars The brake line from the M/C down to the junction is too long. They run about 20.5 inches long. I ordered some about 15.3 inches long. This should let the brake line run in a straight line from M/C to junction. It bows out quite a bit now.
I ordered A TTR 225 M/C to try. It should work well with a single caliper. If this works well I'll get a one piece brake line.
I ordered a set of the M/C and clutch lever, it has a 12.7 mm bore. It should work on the 75 with the dual disk.
I also ordered a couple sets of brake pads. Nice to have spares.
When they come in I'll report back on how they work.


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Hey Leo,

I have an 81 that i am looking to do replace the M/C and clutch lever/assemblies and swap for a shorter brake line for the same reason you mentioned. Did you put those parts on the 81 or on the 75 you mentioned? if on the 81, how'd that workout for you?