Breva 750 oil pressure switch replacement

[Dave.T.]

Hello all
Last week my 750 Breva oil pressure light came on, flickering at first and within a mile stayed on constantly. The engine seems normal and I am hoping it is just a faulty switch. Does anyone have any advice on replacing it as it is very difficult to gain access to.
Many thanks for any advice, Dave.

[MotoGuzzi]

Maybe the oil pressure switch is fine and doing its job. Drop the sump and take a peek inside the sump. Sludge/debris in/on the oil pickup screen?  Have you recently change the oil and filter? Not sure if there is a way to test the OPS by itself or not.

[Chuck in Indiana]

Sure do. If you don't know it, the cam bearing is located by the oil pressure switch. When you have the switch out, whatever you do, don't turn the engine. You'll not only ruin your day, but your whole weekend. 
Here's a picture from the Aero engine thread that shows the hole in the cam bearing and end of the pressure switch.

[Dave.T.]

I last changed the oil and filter about 6 months ago(about 2000 miles). The oil level is checked regularly and has never been low. I have ordered a switch so I will be changing it anyway. If that doesnt fix it I will do as you say. I didnt even know there was a screen in the sump, is this a common problem?
Thanks for the suggestion.

[MotoGuzzi]

I don't know it to be a common problem. However, the same thing happened with me and when i dropped the sump i found a decent amount of sludge and piece of gasket material. Cleaned it all out and the oil light went out.

[v65tt]

Sure do. If you don't know it, the cam bearing is located by the oil pressure switch. When you have the switch out, whatever you do, don't turn the engine. You'll not only ruin your day, but your whole weekend. 
Here's a picture from the Aero engine thread that shows the hole in the cam bearing and end of the pressure switch.

I turned my old v35 lump with the sender removed, the cam bearing moved but was easy to relocate with a carefull prod from a small flat blade

[Dave.T.]

The problem is that I can't get to the switch. It is between the cylinders, the airbox is directly above it and the throttle bodies either side of it. I was wondering if someone else had changed it on this model. If so what is the best way of gaining access to the switch?
Thanks.

[Chuck in Indiana]

Sure, you can do it carefully, but the OP sez it's hard to get to. If it's hard just to change it out, I'll bet he'd really have a tough time finessing that cam bearing..

[v65tt]

My TT has a very similar airbox and night mare access

In the end did mine by removing the battery and disconnecting the airbox from the carbs and sliding the whole unit back untill i could get into the oil pressure switch

Breva layout is almost the same ( throttle bodies instead of carbs)

[Dave.T.]

Thanks for the suggestion. I've just had a look and the airbox assembly goes all the way back to and is hard up against the rear mudguard. It also has several electrical components mounted on it! I dont think it would move without removing a lot of other components.
Thanks.

[v65tt]

if you get really desperate could you unbolt the lower frame rails and lower the engine down a bit?

[Antietam Classic Cycle]

Sure do. If you don't know it, the cam bearing is located by the oil pressure switch. When you have the switch out, whatever you do, don't turn the engine. You'll not only ruin your day, but your whole weekend. 
Here's a picture from the Aero engine thread that shows the hole in the cam bearing and end of the pressure switch.

The B750 is a little different/better:



#9 locates the cam.



and a normal looking oil pressure sender screws into it.



The V50 IIs I've worked on both have the same sort of set-up.

[Chuck in Indiana]

Ahh, that would be an improvement, for sure.. 

[Dave.T.]

I finally got it out! I had to disconnect the linkage on the bottom of the left hand throttle to gain access. Then I cut a 22mm spanner in half to enable me to get a purchase on it. Took about 2 hours of swearing and cut knuckles. I still have to fit the new one when it comes, should be another couple of fun filled hours. Fingers crossed it will then be OK???

[MotoGuzzi]