How to improve front brakes?

I'm in the process of restoring my first project bike - 1982 xj550 maxim. The bike was never really used so it is in good condition. The one thing the PO did was upgrade to braided SS brake lines. However I find the front brakes are very weak and I am unable to lock them even with full force (I'm not taking the bike on the street yet but have tested it in my back alley). I have filed the brake pads, changed the brake fluid, and adjusted the brake lever- none of which has helped. The rotor is clean and in good conditoin. The pads are seated correctly (with very little drag). I did order new pads however when they came in they didn't fit so I will order a second pair today.

Is there anything else I can do? Is it possible to upgrade to a double piston caliper? Or is it normal for these bikes to have weak front brakes? My previous bike was a modern sportbike so maybe I'm just used to something different.

Thanks for any input.

Dave

 

It sounds to me like your lines are flexing and/or your master is not holding full pressure. You most certainly should be able to lock it up.

Has the master and caliper seals been serviced? How old are the lines?

 

Thanks wizard.
I don't know how old the lines are. They look like they are in good shape however given the lack of performance I will have them replaced. Since I also don't know when the seals were last serviced I think I'll replace the following:

New lines
New pads (and shoes)
New seals/bladder

Am I missing anything? Banjo bolts/crush washers?

Again, first timer here.

Thanks,

Dave

 

Should replace the crush washers. Bolts should be reusable but new never hurts.

XJ4Ever, logo in the top right corner can get you what you need quick and at a good price.

 

Shouldn't it take ages for braided steel lines to deteriorate? Whenever the topic of switching to braided lines comes up people mention how rubber lines have a short lifespan but steel lines will outlast the bike.

 

Placing the parts order today.

Thanks again.

 

Sry I didn't see your post Madmusk. I'm not sure how long SS lines last but the ones on there now seem to be a bit too long. If you check my photo gallery you can see there is some slack in the line.... so I think they should go regardless.
Thanks.

 

The lines could be ok. Then again they could not be.

You could rebuild the caliper and master first and then see if that solves your problem. If it did, lines should be fine.

 

SS lines are a bitch to bleed..... could be some air in the lines, but I would suspect the MC and/or caliper is in need of a rebuild....

 

and that ^ was post #500 for me!

 

Agreed. Yes those lines are too long, but this sounds like a MC issue. Give it a really kick ass bleed to be sure no air is there, that front disc should lock up tight when you want it too, shouldn't be soft at all.

Grats on 500, JM.

 

Just orderd rebuild kits for the caliper and MC. When I install them I will bleed the lines again. Just so I'm on the same page- are SS lines hard to bleed because they trap more air than rubber (hence all those little bubbles)?

Thanks for the input everyone

 

SS lines aren't any harder to bleed than rubber lines.

YAMAHAs are just hard to bleed, period. My personal theory is that the rough machining in the caliper bore traps microbubbles that simply take time to "work" out.

I agree it's more likely a master cylinder or caliper issue though. You can get the original brakes as hard as grabbing a rock with SS lines and everything rebuilt.

 

Im gonna bleed mine again they're firm but this makes me think they can be better!

 

TIP***

After you get them as good as they can be, ride the bike for a few days. Run it through a couple dozen front brake "heat cycles." Maybe even give it 100 ~ 200 miles, depending on how you ride.

Then re-bleed. You'll get at least one big fat bubble, guaranteed.