TY175 front brake

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xyeovillian

TY175 front brake

Postby xyeovillian » Thu Sep 01, 2005 4:04 pm

How can I improve my front brake, can't seem to get any feel with it very spongey & won't lock up like the rear brake. I have fitted new Sammy Miller linings when I got the bike about 18 months ago, after todays inspection they were a bit glazed, cleaned up the drum with emery cloth & the linings. So does it mean a new cable as the old one looks old! Alltered the inner cable to work with the new linings when fitted. Will David Lahey be along soon :?:



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Postby David Lahey » Thu Sep 01, 2005 10:34 pm

You know me pretty well whoever you are. I would have been along sooner except for a Father's Day party at my son's Kindy tonight.

No matter how well your TY175 brakes are prepared they will not be as good as a modern disc front brake so I hope you are not expecting too much regarding feel and power.

To get them as good as possible you may need to spend some real money and I'll get to that last.

To get them to a reasonable standard here are some suggestions:

Make up a new cable using the heaviest inner you can get and the outer with the best low friction lining. This should cost less than $15 if you do the soldering yourself.

Use a decent high quality lever assembly. Those cheap taiwanese lever sets cost more in loss of feel and lack of ergonomics than you save in $$$. I use a clutch lever assembly from an RM80X for my TY front brakes. They aren't cheap but work very well.

While you are making the cable, straighten out the steel elbow that has the adjuster on it from the standard Yamaha cable. I suggest you use an oxy torch to soften it and it will straighten nicely. Don't make it completely straight but take out most of the elbow.

Make sure the actuating arm on the brake cam makes an angle of 90 degrees with the cable just as the shoes hit the drum.

Make sure that there is no play in the wheel bearings. Bikes of that age have a tendency for the outer casing of the wheel bearings to become loose in their seats from having the bearings changed many times.

Make sure the shoes have exactly the same radius as the drum. Sometimes it takes 15 times of riding the bike then pulling it apart and shaping the shoes before a new set of shoes touches the drum all over the shoes. This is because new shoes are usually made to fit a new drum while most drums have some wear. Shape the shoes while they are still mounted to the backing plate so you don't accidentally mix them up.
I use a flat file to shape shoes.

OK now for the expensive bit:

Have the hub either resleeved (if it is quite worn) or skimmed (if it is only a little bit worn) by a good machinist. This becomes expensive if you need to cut the spokes to get the hub out. Having this done is very important because the braking surface evenness (imperfections like grooves and rust pits) and the surface finish (on a microscopic scale) are what determine how strong your brake can be. It is surface area in contact with the shoe that does the work. The ideal drum surface is almost a smooth as a mirror and the same applies to the shoes.

I might have forgotten something but that is enough for tonight.



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Postby David Lahey » Fri Sep 02, 2005 7:43 pm

Yes I knew there was something I forgot. What brand are the brake shoes you bought from Sammy Miller? Not all brake shoes are created equal and I haven't bought any from Sammy Miller so don't know about them.
I have found that EBC brand shoes do work great in OSSA MARs, KT250s, Alpinas, Cota 348s and yes last but not least TY250s and TY175s. The best are the MX pattern because they come with water grooves cut already. Yamaha TY shoes are OK but are not as good as the EBC for feel and power. The downside of the EBC is that they have metal particles in the friction material which tends to wear the drums out faster than metal-free friction material like the Yamaha shoes.



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Postby PA » Fri Sep 02, 2005 8:26 pm

David you forgot to mention that Lambswool does not make a very good brake liner.

Very informative reply David. Someone on here always knows the best way to do something.



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Phil
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Drum Machining

Postby Phil » Sat Sep 03, 2005 8:58 am

Hi David
You dont have to pull your wheel apart to machine them just have them done in a turret milling machine (Bridgeport type )I've done TY Yamahas to Sherpa T Bultacos
It takes a little longer to machine but you have'nt got the cost of pulling your wheel apart.
Thanks Phil.



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Postby BJ » Sat Sep 03, 2005 4:15 pm

OK Phil

I'll bring the 348T front wheel with to Sedgwick and you can weld the crack and spin the hub if it needs it.......I won't be overcharged just cause I'm a mug, but Sue will appreciate someone looking after her old relic :oops: ........I mean the bike PA! :lol:

Let me know if you can and how much.


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http://www.parlagully.com

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BJ getting off the track

Postby Phil » Sun Sep 04, 2005 7:37 am

Hi BJ
What I said is that I can machine the brake drum surface without pulling the wheel apart, having said that send me a photo of the hub highlighting
the crack.

Thanks Phil

PTR engineering




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