1981 GS450E Rebuild

[john82q]

pete,
just regular solder like electronic stuff, you will need some active flux (the rosin core wont be good enough for steel) and the right amount of heat.

try soaking the diapharm in fresh brake fluid, it might come back.(or not)


john

[landshark]

Measure your reservoir, i may have one for you.

[pete]

pete,
just regular solder like electronic stuff, you will need some active flux (the rosin core wont be good enough for steel) and the right amount of heat.

try soaking the diapharm in fresh brake fluid, it might come back.(or not)


john

Aaah gotcha! I actually tried whacking a bit of solder on last night before I resorted to pulling the carbs off but it wouldn't stick, so I figured my solder just wasn't the right stuff. I thought I was just bein' silly, but apparently I wasn't too far off, just need some better solder

I should have some fresh brake fluid around somewhere, so I'll give that a go. Thanks for the tip!

Measure your reservoir, i may have one for you.

Cool! Will endeavour to do that tomorrow night as after tonight's effort my reservoir is officially toast. Brittle and cracked while prying it off.

[pete]

Had a bit of a frustrating night tonight.

Was hoping to get the master cylinder out so I could check the bore etc. and get started on adjusting the rear drum brake properly, but didn't quite get that far.

I managed to get the reservoir off, and this is the mess underneath:



The reservoir itself is toast. Don't know if you can tell from the first pic, but the plastic is really brittle and was breaking bits off as I was trying to pry it off the base, and then once I started to get it moving, it flexed a bit and cracked on one side:



The O ring is naturally no good as well, doesn't have much spring left in the rubber, just limp and if you look closely (you can't tell from the pic), you can see where the surface is starting to break down. If I left it too much longer it would've come out in several pieces:



The dust boot won't be keeping much dust out:



I gave the screw bases a good spray with WD (keep meaning to get some Inox to try but haven't got there yet), then tried to unscrew them with some vice grips.



As you can see, that was not successful. I'll have to try my left hand drill bits on the remains, but I can't do that with the hand drill, so not a night time job for those.

At this point, I started attempting to get the circlip from the piston out, but I managed to both lose the spring from the circlip pliers that's used to hold the different heads on, as well as bending the pins on the head that was on there.

I lucked out with the spring and the one I mistakenly bought for the mixture screw on the carbs actually fitted after trimming about a coil and half off the length, so circlip pliers back in action again.

There was also another suitable head in the toolbox so I did manage to get the circlip out:



Not pretty, and guaranteed that needs replacing.

I then foolishly attempted to pry the piston out with a screw driver, but all I managed to do was break one side of the top of the piston off. No damage to anything else thankfully, just the piston which will be being replaced anyway:



So, there she sits for now.

I've sprayed a heap of WD in the orifices to hopefully penetrate a bit around the piston so I can try using compressed air to get the piston out, hopefully sometime over Easter.

And I'll be aiming the piston at a wall when using the compressed air also, don't want any piston related injuries...

[Flaming Chainsaws]

Pete, the brake lever looks exactly like mine. I'd say it's OEM.

If you don't feel like rebuilding the master cylinder, they are available for $35. My master cylinder is brand new with new brake lines . Two finger braking.

[pete]

Pete, the brake lever looks exactly like mine. I'd say it's OEM.

If you don't feel like rebuilding the master cylinder, they are available for $35. My master cylinder is brand new with new brake lines . Two finger braking.

Is yours a slightly brown colour? My brake and clutch levers are different colours, and the clutch looks more OEM to me... but maybe it's the other way around and the brake is the OEM?

Where did you score a master cylinder for $35? I've looked on all the parts fiche's and the best I can do is get a new piston and cup set and new reservoir etc., and those will cost well over $35.

[Flaming Chainsaws]

Is yours a slightly brown colour? My brake and clutch levers are different colours, and the clutch looks more OEM to me... but maybe it's the other way around and the brake is the OEM?

Where did you score a master cylinder for $35? I've looked on all the parts fiche's and the best I can do is get a new piston and cup set and new reservoir etc., and those will cost well over $35.

Actually my brake lever is sort of brown with a purplish tint to it. I repainted it black now. My clutch lever is black. Hmmm....

Found it on eBay. It was NOS and OEM. Also complete.

Here's an aftermarket one.

http://cgi.ebay.com/ebaymotors/FRONT-BRAKE-MASTER-CYLINDER-SUZUKI-GZ250-GS425-GS450-_W0QQcmdZViewItemQQhashZitem19c4d99fbfQQitemZ110676778943QQptZMotorcyclesQ5fPartsQ5fAccessories

I guess I got lucky and found an OEM one . They have some kits available.

http://shop.ebay.com/?_from=R40&_trksid=p5197.m570.l1313&_nkw=gs450+master+cylinder&_sacat=See-All-Categories

[Charlie G]

Pete,

These photos of your brake parts are impressing upon me the need to tear into my brake systems.

cg

[pete]

Actually my brake lever is sort of brown with a purplish tint to it. I repainted it black now. My clutch lever is black. Hmmm....

Found it on eBay. It was NOS and OEM. Also complete.

Here's an aftermarket one.

http://cgi.ebay.com/ebaymotors/FRONT-BRAKE-MASTER-CYLINDER-SUZUKI-GZ250-GS425-GS450-_W0QQcmdZViewItemQQhashZitem19c4d99fbfQQitemZ110676778943QQptZMotorcyclesQ5fPartsQ5fAccessories

I guess I got lucky and found an OEM one . They have some kits available.
http://shop.ebay.com/?_from=R40&_trk...All-Categories

Hmmm... not sure.

I know mines been dropped a few times over the years going by scrapes and things, so maybe both of our brake levers are after market?

As for a master cylinder, I'm not real keen on an after market one from eBay as I don't know where it came from. Kits may be ok, but I'll probably stick with a dealer here or get them shipped from Boulevard Suzuki again.

Pete,

These photos of your brake parts are impressing upon me the need to tear into my brake systems.

cg

If you're not sure on the state of them Charlie, I'd definitely do it. Not something you want failing in the middle of a ride...

[landshark]

Pete, do you have twin calipers or single?
The reservoir i have looks like yours(so measure it and let me know), it has been fitted to the bike, but i took it off and i am now running an radial master cylinder.
If you have twin discs i maybe able to get another radial for you.

[pete]

Mine's just a single disc up front, so I'll give it a measure tonight and let you know.

Is this just the reservoir or the master cylinder as well?

Either way, it will be a great help if it fits

[pete]

Ok, measured it up tonight.

Reservoir is 70mm long x 37mm wide x 30mm deep without the lid.

The circular bit that seats in the master cylinder is about 27mm diameter.

If you're talking about the whole master cylinder as well, then according to my manual the bore of the cylinder should be about 14mm

Other than measuring that up, got nothing else done tonight...

[landshark]

I'll measure the reservoir tonight for you, I dont think the whole thing will suit as it is off a twin caliper, but the reservoir might?

[herostar]

That master cylinder is gross!

If you're already buying new brake parts, why not do the big-rotor swap that's fairly common on the bigger bikes. I think all you need is the larger rotor, an adapter plate (from someone on the forums here, or homemade if you're mechanically inclined), and the new caliper. We can do the same swap as the dual-rotor front bikes, but just with a single rotor.

I'd have to do a little digging to get the specifics, I just remember this option from when I was redoing my brakes last summer...

[pete]

I'll measure the reservoir tonight for you, I dont think the whole thing will suit as it is off a twin caliper, but the reservoir might?

I did the Babbitts Online search and looks like the reservoir is the same for heaps. Part number 59687-45100:

GN400T (1980)
GN400T (1981)
GN400TX (1980)
GN400TX (1981)
GN400XT (1980)
GN400XT (1981)
GN400XX (1980)
GN400XX (1981)
GS1000G (1980)
GS1000G (1981)
GS450E (1983)
GS450ET (1980)
GS450ET (1981)
GS450ET (1982)
GS450EX (1980)
GS450EX (1981)
GS450EX (1982)
GS450EZ (1980)
GS450EZ (1981)
GS450EZ (1982)
GS450ST (1980)
GS450ST (1981)
GS450ST (1982)
GS450SX (1980)
GS450SX (1981)
GS450SX (1982)
GS750E (1980)
GS750E (1981)
GS850G (1980)
GS850G (1981)

So I dare say it's the right one.

There's no part number for the cylinder, but the piston and cup set only seem to fit 400/450's mainly with a few of the larger single disc models, so I'd say you're right that the cylinder will be no good.

That master cylinder is gross!

If you're already buying new brake parts, why not do the big-rotor swap that's fairly common on the bigger bikes. I think all you need is the larger rotor, an adapter plate (from someone on the forums here, or homemade if you're mechanically inclined), and the new caliper. We can do the same swap as the dual-rotor front bikes, but just with a single rotor.

I'd have to do a little digging to get the specifics, I just remember this option from when I was redoing my brakes last summer...

You got that straight! Disgusting...

I'll have to look into the rotor swap. If it means I need to make brackets and things it's probably beyond my capability though and I wouldn't be confident doing that for something to do with something critical like brakes.

I also need it to pass a roadworthy certificate.

However, definitely worth looking into, time for some searching around over Easter.