1979 GS750LN Front Master Cylinder Reservoir

[rustynissan]

Looks like PO swapped out the handlebars from the swooping downward style to the slightly swept backwards and more straight style. The bottom of the reservoir opening is set at an angle, causing the master cylinder reservoir to sit at an angle while riding and really testing the seal on the cap all the time. I see other GS750 models with a reservoir that is just a normal cylinder with flat cut top and bottom, anyone know if I can just swap them out? If so, know a good place to scoop one up?

 

[Guest]

You can as long as you’re not using a small one meant to only operate a single front brake to one that has dual front brakes. I can’t remember that actually piston sizes off hand, 10 and 12??? Someone will chime in on the specifics I’m sure. Easy to find new ones online, eBay, Amazon, or on here if you want a good used one.

 

[rustynissan]

You can as long as you’re not using a small one meant to only operate a single front brake to one that has dual front brakes.

Yeah, I was hoping to keep the piston housing (mirror mount and brake handle integrated) and just replace the reservoir. That assembly sits nice and flat now. Here's a really grainy picture:

 

[johnod]

That looks damaged to me.

 

[hannibal]

The reservoir looks slanted in the parts diagram as well so I think it's fine. Other than the slant, it looks very similar to my 750 non L MC. I'm guessing the reservoirs are interchangeable.

 

[johnod]

The O ring 750EN is the same part number, so must be same diameter at least.

 

[rustynissan]

That looks damaged to me.

It looks super weird on these handlebars that don't curve downwards! Like Salvador Dali designed it, haha! Good catch on the o-ring, that gives me confidence. I'll dig one up somewhere and try it out, thanks!