Brake questions for the new guy

[ReelRacin57]

Ok I just got my first bike an 82 xs400 maxim got it for 300 bucks got it running and driving around the back yard the thing doesn't have breaks pulled the master cylinder apart needs seals bad but I don't know what model it is to get a rebuild I measured the piston in the mc aND I get 12.58 mm idk if I should just upgraded and what I should get.or rebuild it but idk what to get mikes xs is not clear at all for the 82 max. Any help to point me in the rite direction is appreciated I'm also going for a tracker look so if an up grade I'm looking that way thanks again

 

[16VGTIDave]

Welcome @RealRacin57!

I must admit that it was difficult to read your post. Even the spammers we see here on occasion use punctuation, paragraphs, and other other accepted writing techniques. Please consider using your grade school writing skills, you'll get more responses to your posts. End of lecture. [emoji2]

MikesXS is primarily focused on the XS650, and they carry few parts for 400's. Even fewer for the DOHC bikes. If you have a bike shop close to you, I'd suggest stopping in there and asking them if they can get you a rebuild kit. My local shop only stocks oil filters, but they can get most anything in 2 days. Their prices are cheaper than online once shipping is factored in, and I'm helping keep my neighbors employed.

Have you checked the caliper to see if it is seized? I should also ask if you are thinking about doing a fork swap, as that will change the brakes required. If so, rebuilding the master cylinder would then be pointless.

 

[ReelRacin57]

I would like to do a fork swap, but I'm don't know where to start with what is compatible. If its cheap enough i might start with that. trying to get it road worthy first, than do my customizing to it.

 

[16VGTIDave]

Ok. If the rest of the front brake components are in decent shape, then a rebuild kit would be cheap enough to be worth while. Just spend the least you can to get the bike inspected and on the road. The reality is that most of the parts that are required to be inspected will be replaced when you start modifying the bike. Buy or borrow used parts, if needed, to pass an inspection. Then you can ride it for a week to make sure it is reliable before you tear into it.

Replacing the forks can be done a couple ways. You can find 35mm forks to fit your clamps. Get a complete front end with wheel, fender, brakes, etc and install it. A 35mm fork isn't found on modern bikes, but the XS650 used it, as well as some older motocross bikes. The slightly more difficult option is to replace the entire front end including the steering stem. Any fork and wheel is then an option. Some can be installed simply by changing the bearings, others require modifying or replacing the steering stem. That will take some effort, but will be worth it in the long run.

 

[ReelRacin57]

All you said is very helpful. I think I'm gonna leave the forks alone for now. With that's being said will a xs650 caliper and master cylinder fit on the maxim?

 

[16VGTIDave]

I don't know for certain as I've never done it. I don't think the caliper will work at all. The master should work, though it may not fit well with the controls. There is nothing special about the XS650 master, so I wouldn't go looking for one. If you find one in working condition for cheap, that's a different story.