Master Cylinder

[banksy]

https://img15.imageshack.us/img15/227/cimg3602d.jpg
https://img15.imageshack.us/img15/cimg3602d.jpg/1/w3648.png

I have a problem with my XT350 master cylinder. The piston is siezed and wont move. To make matters worse the circlip has rusted in aswell. I tried getting it out with circlip pliers but no joy. Is there a way of saving this or do I need to scrap the master cylinder.
How much will yamaha charge me for a new one or are there any alternatives?

Cheers
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banksy
-CG125 07- -GS500F 04- -CBR600 98- -FJ1200 86- -XT350 91- -CBR900RR 01-

[Ichy]

You might be able to save it by leaving it soaking in plus gas or paraffin for a few day but there is a good chance that the bore will be damaged causing failure of the new piston seals in a short time. You might even be able to bore it out and then hone the bore but I think its way too much trouble.

I would look at ebay first. Any MC fitted to a bike with a similar setup, number of discs, caliper size, etc, should be fine.

Last SH one I brought was about £5 but you can expect to pay £20-£30. Not too bad when a rebuild kit is likely to be £15-£25.

No idea on the cost of a replacement but I do know a good universal MC is about £80-£90!

Actually > cheap

The angle won't matter once the lids on

Wemoto do one for about £69.
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[banksy]

im keen on keeping the mirror hole and brake light

would one from an xt600 be ok?
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banksy
-CG125 07- -GS500F 04- -CBR600 98- -FJ1200 86- -XT350 91- -CBR900RR 01-

[Ichy]

The link to the ebay one has the mirror hole and brake light switch? Just a funny angle.

Dunno, I was going to suggest one but I have no idea if the system is similar. The worst that can happen is that the brakes will be too sharp or the lever will only need a small travel to lock up the brakes.

Personally, if they are both single discs and it was cheap enough then I would buy it.
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[banksy]

ok doesnt sound too bad, could probably find a way around that

theyre both single discs but the 600 has 2 pistons
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banksy
-CG125 07- -GS500F 04- -CBR600 98- -FJ1200 86- -XT350 91- -CBR900RR 01-

[Kickstart]

Hi

Personally I would lever that circlip out (if you buy a rebuild kit it should come with a new circlip). Clean up around it and use various tools to lever one end out. It should come.

While you can use other master cylinders get one that is designed to push about the same amount of fluid (ie, area of the pistons is about the same, assuming both are opposed piston calipers, or both are sliding calipers). Using one from a twin disk setup would probably give you very dead feeling brakes requiring loads of lever pressure.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[banksy]

did try prising the circlip before but its just solid

think il try the 600 one
if the brakes are sharp il just throw some air in the lines
ok thanks guys
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banksy
-CG125 07- -GS500F 04- -CBR600 98- -FJ1200 86- -XT350 91- -CBR900RR 01-

[Kickstart]

Hi

Try a bit more. Bit of penetrating oil to help shift the corrosion. If you have a kit to rebuild it then pretty much everything you can see there will be replaced anyway.

Problem isn't so much that they will get too sharp. You can either land up with a very dead feeling lever, requiring loads of lever pressure for not much effect. Or a very spongy lever but not requriring much lever pressure (so yes this might be too sharp, but would also mean pretty much any air in the system would result in the lever coming straight back to the bar).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Ichy]

From the look of the photo the circlip is corroded to the piston. Have you tried giving the end of the piston a sharp tap to break the corrosion? Not too hard though, your not trying to force the piston down the bore.

Sorry for the dumb question but have you tried using a center punch to force the circlip round?
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[banksy]

erm no i havent... just to twist it round and break the seal?
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banksy
-CG125 07- -GS500F 04- -CBR600 98- -FJ1200 86- -XT350 91- -CBR900RR 01-

[Ichy]

Pretty much.

You don't have a lot of room but my idea is to hit the edge of the circlip hole (for the pliers) sideways or in toward the center.

You might be able to prise it with a punch if your careful.
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[banksy]

just gave it a quick go

its totally fused all the way around,

even if it could move im sure it would snap rather than come off

banging in the piston did nothing

it hasnt moved for 11 years... i think its scrap
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banksy
-CG125 07- -GS500F 04- -CBR600 98- -FJ1200 86- -XT350 91- -CBR900RR 01-

[Ichy]

[Kickstart]