Brake Squeal.

General discussion about Street two-stroke Suzuki motorcycles.

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jabcb
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
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Re: Brake Squeal.

Post by jabcb »

EBC’s MD series is there old design with a solid central plate. The VMD series is the new much-better-looking design that I have.

Suzuki GTs have two different disc ODs.
The GT500/GT550/GT750 use the large OD disc, which is VMD3019. The GT250/GT380 use the small OD disc, which is VMD3014.

The GT250 cafe project has the salty_monk upgrade, which was developed by members of the Suzuki GS Resources forum.
This upgrade works on the GT250 & GT380.

The upgrade consists of:
1) an adapter plate that you buy from a GS forum member
2) a large OD disc. I used the VMD3019 but the forum lists other choices.
3) a two piston caliper from the forum’s lists of choices. I used a Kawasaki Ninja caliper.

The old GT-series disk brake setup uses round brake pads & was designed for the caliper in front of the fork tube.
The upgrade uses rectangular pads and calipers that were designed for use behind the fork tube.
It gives you much more powerful brakes & moves the weight closer the fork pivot axis. Plus it looks cooler.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Glyn.G
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Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Cheers jabcb,
Just checked the EBC website again and found the VMD3014 disc but unfortunately they are out of stock " typical ". I have e-mailed them to confirm the correct fit and price so hopefully I should be able to get one soon.
How did you locate the caliper behind the fork leg did you just swap the fork legs over and fit the disc on the left side of the wheel.
I can't seem to find the GS forum that has the member who supplies the brackets or calipers.
Kind Regards,
Glyn.
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jabcb
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Joined: Mon Dec 13, 2010 4:32 pm
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: Brake Squeal.

Post by jabcb »

Look at the parts diagrams for the GT380 & GT750.
Speedo drive has to stay on the left.
Swap the fork tubes.
There is a dust cover that is attached to the hub that will now attach to the disc. That makes it too thick so either cut it down a bit or get the GT750 dust cover.
Used plastic screws to fill in the hub holes left by removing the disc from the right side.
Used a custom brake line — they have lots of different fittings so its easy to run the line where you want.
The kit only includes the adapter. You need to separately buy the caliper & mounting bolts.

GS forum member, salty_monk, sells the kit.
The post about it is really long & includes the list of calipers that work. I got a used one via eBay.
http://www.thegsresources.com/_forum/sh ... n-78-Skunk

The post also includes a list of used discs that will work. These disc are lighter because they weren’t designed for the round brake pads used in the early 1970s. But you need a drill press or shop to enlarge the mounting holes.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Glyn.G
To the on ramp
Posts: 207
Joined: Fri May 30, 2014 5:41 am
Country: UK
Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Cheers jabcb,
I found the GS forum and have posted a query hoping Salty Monk will get in touch. I can't seem to contact him direct as I haven't been on the forum long enough. I don't know if he will post the bracket all the way to Blighty or maybe he could give me the dimensions to make my own.
Regards,
Glyn.
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jabcb
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: Brake Squeal.

Post by jabcb »

His forum member name is: salty_monk
Be sure to include the underscore.

Unfortunately the GS forum topic with lots of images was screwed over by the Photobucket policy change.
Here is a pic from that topic with a different rotor:
Image

The kit includes:
1) the roughly triangular-shaped plate that attaches the caliper to the forks
2) a small cylindrical spacer that is under the lower left bolt in the pic
3) an adapter disc for the alternate discs

The adapter disc is not used with the EBC VMD3019
Just in case you didn’t notice, I’ll repeat my statement:
For the GT380 with the stock caliper, use EBC VMD3014
For the GT380 with this salty_monk upgrade, use EBC VMD3019

The alternate discs have the correct bolt pattern but not as much offset as the stock Suzuki disc.
You use the adapter disc to get the correct offset. It goes between the disc & the hub.

Also, the bolt holes are a little too small on the alternate discs. The adapter disc is a useful template for drilling out the holes to the correct diameter.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Glyn.G
To the on ramp
Posts: 207
Joined: Fri May 30, 2014 5:41 am
Country: UK
Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Cheers again jabcb,
I think I've got all that info, I think I'll try the standard caliper with the VMD3014 first. EBC stated the disc will fit straight onto the existing hub without needing any adapter and should eliminate any brake noise. I hope they're right! Does this sound right to you about no adapter needed.
Regards,
Glyn.
Glyn.G
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Posts: 207
Joined: Fri May 30, 2014 5:41 am
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Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Just as a matter of interest would it be possible to mount a L/H GS550 caliper with the more modern rectangular pads to the R/H side of a GT380. I know the GS caliper is designed to go behind the fork leg but it looks like it could be mounted on a GT380 in front of the fork leg.
Don't worry I'm not going crazy I'm just running ideas around in my head, and believe me there's a lot of empty space in there to fit more.
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Alan H
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Re: Brake Squeal.

Post by Alan H »

GS1000 caliper fits. So do lots of others. Do a search on here.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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jabcb
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Re: Brake Squeal.

Post by jabcb »

Alan H wrote:GS1000 caliper fits. So do lots of others. Do a search on here.
+1 on that

Suzuki used the same caliper for lots of the early GS-series four strokes.
Some, if not all, of the rectangular-pad single-piston calipers from the early four strokes can be used on the two strokes.
This is an easier upgrade because you can keep the stock disc.

So you should make your caliper decision before buying a new disc.
For the stock caliper or a GS-series rectangular-pad single-piston caliper, use either the stock disc or EBC VMD3014.
For the salty_monk two-piston upgrade, use a GT500/GT550/GT750 stock disc, an EBC VMD3019, or one of his other choices.

While doing either upgrade, I suggest that you upgrade to a modern stainless steel brake line.
The custom SS brake line we just got for the GT250 cafe project was around $70.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Glyn.G
To the on ramp
Posts: 207
Joined: Fri May 30, 2014 5:41 am
Country: UK
Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Hi,
I did a search as Alan suggested but it didn't come up with much only that the mounting bolt hole centres are slightly different on the GS calipers, about 5mm-6mm. Has anyone else found this, it would be great if I could find a drawing with the actual dimensions on.
Regards,
Glyn.
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jabcb
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Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
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Location: southwestern Pennsylvania

Re: Brake Squeal.

Post by jabcb »

When you switch the caliper you also have to use the mounting bracket that was intended to be used with that caliper.

The sleuthing can be done although its rather tedious. For example, start with the 77 GT550, which has either a Tokico or Asco caliper.
Mounting bracket for Tokico is part #: 59100-33110 ==> 59100-33111
http://www.partzilla.com/parts/search/S ... parts.html
Mounting bracket for Asco is part #: 59150-34020
http://www.partzilla.com/parts/search/S ... parts.html

59150-34020 was used on lots of 4 strokes, including the 1979 GS1000EC
http://www.partzilla.com/parts/search/S ... parts.html
The fork tubes on the 1979 GS1000EC are part #s: 51130-49001 & 51140-49001 (left & right have different #s)
http://www.partzilla.com/parts/search/S ... parts.html

51130-49001 was also used on the 1980 GS1000E
http://www.partzilla.com/parts/search/S ... parts.html
The 1980 GS1000E has calipers with rectangular pads. Caliper assembly part # is 59300-49020
http://www.partzilla.com/parts/search/S ... parts.html

Here is a partial list of the bikes with the rectangular-pad caliper, 59300-49020, that will fit the two stroke forks:
http://www.partzilla.com/parts/detail/s ... 49020.html

The bracket that attaches the caliper to the fork has different part #s for the right & left side, so make sure you get the correct one.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Glyn.G
To the on ramp
Posts: 207
Joined: Fri May 30, 2014 5:41 am
Country: UK
Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Thanks jabcb,
Great information, I've found a couple of GS1000 calipers with brackets on e-bay but I just need confirmation on the dimension of the locating bolt hole centres on the caliper holder ( bracket ). I've messaged the sellers and asked for the dimension but no reply yet.
I've taken a rough measurement with a steel rule and it looks like they are 72mm-73mm between hole centres on my GT380. My eyesight ain't what it used to be.
Again thanks for all the help.
Glyn.
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: Brake Squeal.

Post by sportston »

I got a caliper and bracket off a gs750 on my gt380. Straight fit, no mods needed.
Glyn.G
To the on ramp
Posts: 207
Joined: Fri May 30, 2014 5:41 am
Country: UK
Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: Brake Squeal.

Post by Glyn.G »

Hi,
Sorry it's been a while but here's the update. In the end I purchased a GS1000 caliper and refurbished it, new piston, seal and dust covers. Fitted straight on with no mods needed and boy oh boy does it stop quick even on the standard disc, and no annoying squeal.
Thanks for all the help on this subject. I think if it wasn't for this great forum I'd have gone totally nuts by now trying to solve the problem.
Many Regards,
Glyn.
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Alan H
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Re: Brake Squeal.

Post by Alan H »

I've got 2 GS1000 calipers on the 550 and it stops very well!
viewtopic.php?f=2&t=11247&hilit=+earwig" onclick="window.open(this.href);return false;

And a pair on the GT750 too - so they both stop....

There's a 1200 Bandit master cylinder on both for the twin disc setup.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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