K75 Coolant Reservoir - Buyer Beware

[Motorhobo]

I've watched the plastic sight glass on my 95 K75 deteriorate over time until it finally started to crumble and crack and look like crap to boot. Earlier K's (C, RT, S) apparently had rather than a molded plastic sight glass just two outlets with a clear section of plastic tubing affixed with two hose clamps so you could replace it if it got gummy and opaque. Having checked the fiche and seeing there was only one part # the K75, I assumed all K75s were the same and I went on eBay to replace my coolant overflow bottle. I got one supposedly from a 92 K75 for $9. It had the plastic sight glass on the pic so I assumed it was right without comparing it too closely with the original part I was replacing. When it arrived, I saw that its plastic sight glass was starting to corrode as well and what's worse, the outlet nozzle was on the front side instead of the rear. I could not get it in position because the nozzle on the front bumped up against the frame and conflicted with the lines running up from the right footpeg.



So the eBay purchase was a waste of time and money and I ended up getting a new coolant overflow reservoir from Bob's for $50 (ugh). Bob's only had the bottle with the outlet on the rear of the unit. After comparing the K75 with the K75 RT, S and C on the fiche, I saw that the latter all specified the unit with the outlet on the front and the plastic tube instead of the molded plastic sight glass. I still haven't been able to find any part on the fiche that has the molded plastic piece and the outlet on the front.

So -- a word of caution -- if you want to find a cheap replacement for the cheezy coolant reservoir make sure you do more due diligence than I did, otherwise you will have a useless part and end up at the dealer at the end of the day anyway.

Van

[Scott_]

In April of '93 BMW changed the coolant bottle design from the front outlet style to the rear outlet style, per the attached SB.

Reason for change to accommodate more routing room for wiring and hoses.

[Grim]

Just throwing this out. Don't know if this will work or not but on bikes with ABS II the reservoir was relocated and mounts off the bolts for the rear inner fender. Its made of a single materiel instead of having the sight glass glued to the side. 

 Is that an option for earlier bikes?

[Motorhobo]

I don't think that would work -- the 2V Ks have then EFI laying flat directly under the seat and are held in place with a bracket that takes up all that space where the bottle appears to be in your pic.

V

[pdg]

You could probably get that later/clear coolant bottle in an earlier one, but you'd be needing to chop up the ECU mount / tool cubby under the seat.

Not sure if your secind pic is a modified ECU tray or whether it's off a low seat version, but there's more to it than that on mine.

[Motorhobo]

No tool cubby on the low seat which both of my K75s are and no room for anything else in there -- so unless anyone can come up with a way to replace that plastic sight glass with something more durable, a new unit is really the only option. You rarely if eve see them on Beemer Boneyard or Drake's K-Bike Parts site.

[Grim]

Was just a thought. I haven't messed with a 2V bike and that picture I found looked like it might fit. This is where we need Duck he would probably know or be able to dig through his shed and give a yes or no.

This is where that second picture was from. Doesn't look like a low seat but after looking for more under seat pictures I guess there is a tray already removed.
http://www.ibmwr.org/ktech/k-battery/