Found source for discontinued 77-79 front caliper pistons

[Guest]

I have a '78 GS 750 and when I went to rebuild the front calipers found that the pistons are discontinued. Mine were trashed. Only Wemoto (in UK) carried a replacement, was going to be pricey. I did some research and found out that the Yamaha XS series and Honda GL 1000 both used nearly the same size piston along the way. Stock size for the gs750 '77-79 is 41mm tall and 38.10mm OD, The XS/GL replacements I found are either 38.0 or 38.1mm OD, and 41.25 to 41.3 mm tall.

I went with these from HVC cycles in the US, they are stainless, 38.0mm OD and 41.25mm tall http://www.hvccycle.com/brake-caliper-pistons.html $27.75ea P/N HVC200106-5. I did not find the larger diameter 38.10 pistons from other makers until after I placed my order, or I would have gone with them to stay with factory spec. Although these are 0.1 mm under spec, they sealed nicely with new factory seals, function great, and have not leaked.

Here are the sources I found, hopefully this will simplify the search from some others on here. Most of these are stainless, but not all.
http://www.hvccycle.com/brake-caliper-pistons.html
http://www.ebay.com/itm/Yamaha-XS-6...Parts_Accessories&hash=item4169f3d1ad&vxp=mtr
http://www.partsnmore.com/parts/honda/gl1000/?filters[fitting]=custom&filters[page]=2
http://motorcyclesolutionsllc.com/h...s400-sr500-xs650-xs750-gl1000-mcs-011-mcs-011

These should work for GS 750's from 1977-1979, B, C, E, EC, EN, and N models. This is just my research, so double check your specs and see what will work for you. I am just listing what worked for me, if you choose to go with any of these you assume all of the risk for the change. I only used HVC cycle, and can not vouch for any of the other manufacturers.

 

[Guest]

Thanks for the info.

 

[cornishgs]

for my gs550 I had early calipers with 38 x 32mm pistons couldn't find any so have used some pattern ones 35mm x 38mm from Honda cb900

no fitting problems also suzuki gt250 and gt 550 list caliper pistons as 38mm x 35 so lots around on ebay also stainless ones .

 

[tatu]

A handy post, thanks for sharing.

 

[jfranzino]

Thanks for the great info CrazyCloud! Quick sanity check: the stock rear caliper pistons are the same dimensions, correct?

 

[Guest]

Jfranzino, I think the rears are the same diameter but much shorter, like 38mm x 22mm or so?

 

[tanner_03]

Thanks CrazyCloud, found mine through the HVC link you provided.

I've also got a 1978 GS750, but my (super rusted) front brake piston measured about 43mm OD, so maybe it wasn't stock? I went with the 42.8mm x 38.75mm "Kawasaki Brake Caliper Piston: Replacement for Kawasaki Part Number 43048-006" on this page - http://www.hvccycle.com/brake-caliper-pistons.html

The top of the piston is slightly different, such that the cap from my old one doesn't fit. But it seals well, no leaks. I also got the seal kit from HVC - Kawasaki KH,KZ Brake Caliper Rebuild Kit, 32-1289.

 

[hannibal]

Suzuki sells rebuild kits including (steel?) piston for both the 38mm and 43mm calipers.

 

[roeme]

Suzuki sells rebuild kits including (steel?) piston for both the 38mm and 43mm calipers.

Any place online to get them?

 

[hannibal]

Any of the OEM dealers carry them. My favorite is PartsOutlaw.com. We use the code BANG to get free or reduced shipping. Not sure that would help with shipping to Switzerland.