Breva 750 Transmission oil and shaft drive oil change

[willard]

I should be picking up some 15w-50 oil for my Breva soon, and I want to change the other oils in it as well.

I know the book calls for 85w-140 for the transmission and 80w-90 for the gearbox.

First off, lets clarify. Is the "transmission' the bottom end of the engine and "gearbox" the shaft drive, or is it the other way around???

Secondly, I'm hoping changing these fluids will be fairly self explanatory, but for the life of me, I can't find any numbers or write ups on how much oil is to be added to each of these, or how to change them.

Help me wildguzzi, you're my only hope.

[theoneandonly]

g/box is 80/90
transmission is 85/140
fill g/box to level in the side
transmission , fill thro' plug at the rear , spin the wheel to coat the gears , until you can't get anymore in !
the proper way to do it is to have the swinging arm parallel to the floor . 

[willard]

g/box is 80/90
transmission is 85/140
fill g/box to level in the side
transmission , fill thro' plug at the rear , spin the wheel to coat the gears , until you can't get anymore in !
the proper way to do it is to have the swinging arm parallel to the floor .

Thank you, but you didn't clarify the terms for me, so I'm still confused.

And how do you empty out the old oil???

[GMies]

Thank you, but you didn't clarify the terms for me, so I'm still confused.

And how do you empty out the old oil???

USE Book:
 https://www.google.fi/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwims5363KXXAhUJpKQKHXjKD80QFgg1MAI&url=http%3A%2F%2Fcadrecycle.com%2Fmanuals%2Fmanuals%2FBreva%2520750%2520IE%2520MY%252006%2520English.pdf&usg=AOvVaw0ww_JsLonKtO1HTVabudMK

[willard]

USE Book:
 https://www.google.fi/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwims5363KXXAhUJpKQKHXjKD80QFgg1MAI&url=http%3A%2F%2Fcadrecycle.com%2Fmanuals%2Fmanuals%2FBreva%2520750%2520IE%2520MY%252006%2520English.pdf&usg=AOvVaw0ww_JsLonKtO1HTVabudMK

Thank you, but, again, this answers none of my questions.

[Antietam Classic Cycle]

I prefer the terms engine (15w50), transmission (thing w/five gears in your case - 80w90) and rear drive (85w140).

[Cliff]

I think what Willard is saying, and I agree, is that that book, which he has indicated knowledge of, is bloody useless especially in the points mentioned. I did give me good information on how I should get on and off the bike though. I had to search the web to find anything useful.

The rear wheel has three bolts, top, rear, bottom. Undo top and bottom to drain. Then remove rear and replace bottom to fill from the top untill it starts to come out the rear.

For the gearbox there is a rear facing bolt (rotate rear exhaust crossover to increase clearance) to drain and a bolt on the side of engine. You fill it from the side when on side stand and stop when it starts to come out when level.

[Antietam Classic Cycle]

I never use the level plugs on any old Guzzi. For the rear drive level plug to be correct, the swingarm would need to be perfectly horizontal. On the small-block 5 spd. transmission, you have no choice - the level plug is the fill plug. I prefer to drain thoroughly, measure the oil to put back in a "Ratio Rite" or other measuring cup and fill.

[willard]

Thank you two for you useful responses.

[pete roper]

If you're new to the B750 be aware that they and the other twin TB 750's sometimes suffer from the strange phenomenon of them suddenly and for no apparent reason *Disappearing* all their engine oil. I know of no definitive cause or why it happens but the Pistons and rings were redesigned when the single TB models were launched and the problem vanished!

For that reason I always encourage owners of twin TB 750 smallblocks to invest in a sump extension. Not because it will cure the problem but because the extra litre of oil it gives you means that you have a better chance of catching the problem if it occurs before the engine makes the 'Dogga-Dogga' noise! The stock 2 litre capacity is adequate for cooling and lubrication needs but if they do decide to do the 'Use the oil' trick they use it fast.

Pete

[sign216]

I wrote a tutorial on changing the transmission oil (double-click on the photos for text);  https://www.flickr.com/photos/sign216/albums/72157626993357143

And the Yahoo group, in the Maintenance + Repair section on the Links page has even more guides;  https://groups.yahoo.com/neo/groups/MG_750/info

Happy wrenching,
Joe

[willard]

Thanks for the help.

So I'm changing the engine oil right now. The oil bolt nearest the front wheel is really hard to get off, and I don't have the proper size box wrench. I was using an adjustable wrench, but it kept slipping and, I don't want to strip the bolt.

Is it okay to leave the bolt on and fill with new oil? I got almost 2 quarts out of the rear bolt, which seems like that would be most of the oil anyway.

[willard]

Also I just found a large hole in my muffler.

[willard]

A peek under the other mufflers heat shield reveals a similar hole.

And the mufflers are held on by these clamps. The left one is not tight, and I can't get it to be very tight either.

[Muzz]

Willard, the clamps are almost definitely seized. The quality of the clamp is fine, they are all stainless and therein lies the problem. Luigi does not put any nickel antiseize on the threads!~!! The bolt in all likelyhood is screwed.

I replaced the clamps with ones that have a stainless band but a steel bolt and nut. I liberally applied antiseize on it. This enables you to fully tighten the muffler on to the pipe. Italians.

Just looking, I see Pete has put the engine capacity at 2lits. Mine is an early one and the book says 1.8lits. On my first change I measured the 1.8lits and it sat dead on the full mark. This is with the oil warm, bike level and dipstick screwed in. I think on some later models they changed things a bit.

Mine has never done the "chuck the oil" bit, but I still check it regularly. Make sure the dipstick is tight. Some (including mine) did the old "send the dipstick in to orbit" thing. Fortunately the slippery foot syndrome manifested before the dogga dogga one did.

[Chuck in Indiana]

Thanks for the help.

So I'm changing the engine oil right now. The oil bolt nearest the front wheel is really hard to get off, and I don't have the proper size box wrench. I was using an adjustable wrench, but it kept slipping and, I don't want to strip the bolt.

Is it okay to leave the bolt on and fill with new oil? I got almost 2 quarts out of the rear bolt, which seems like that would be most of the oil anyway.

You will get about a 1/4 to a half cup of old oil from the front drain. You know.. proper wrenches are cheap. 

[willard]

Thanks guys. I'll put a new band on that muffler.

I took a trip up to North Carolina to see my parents yesterday. The bike did fine. Although I *almost* lost it with too much back brake after a rain shower.

I checked the oil probably five time during that 200-250 mile round trip. Pretty sure I overfilled it a bit, because it was leaking around the bottom of the engine casing and I couldn't figure out where it was coming from. The oil was full, and every time I checked it looked clean.

[Muzz]

Pretty sure I overfilled it a bit, because it was leaking around the bottom of the engine casing and I couldn't figure out where it was coming from.

Where from can be important. If you look underneath at the area between the motor and the bell housing there is a small slot. That allows any oil that gets in to the clutch area to drain away. If it is coming from there there are two possible causes, a leaking engine main seal or a leaking main seal on the gearbox. The smell of the oils is different; gearbox oil smells somewhat acrid. Placing a paper towel underneath after a ride may help localise where the oil is coming from.

Mine actually had a warranty issue with the gearbox seal. They also put another "O" ring in for the clutch pushrod seal.

[willard]

I left the bike outside overnight and there were no oil drips on the pavement this morning. It's possible that it was oil from the change that just got on the engine casing. I'll keep an eye on it in the meantime.

[Muzz]

You will get about a 1/4 to a half cup of old oil from the front drain. You know.. proper wrenches are cheap. 

It is 22mm from memory. I had to buy a single socket for my 1/2" drive socket set; it is not a "standard" size.

[malik]

On the V7C (same engine), the front drain plug is 19mm, the rear is 17mm, as is the gearbox drain plug, and the  filter is 13mm. Seeing as you really should take the filter bolt off with a socket to avoid breaking the fins on the bottom of the engine,, it would be a good idea to get a socket set. Leaning on a hefty bar on that front drain plug makes it a lot easier to get that one moving - as it is at the front in the weather, there is initial resistance. Do yourself a favour & get reasonable tools, an adjustable wrench just won't do. A socket set, a set of ring/open end spanners, and some allen keys make life easier.

Note with the allen keys, you will need to have a set which includes a 7mm for the front brake caliper.  7mm is an uncommon size, but not unusual.You should have a 14mm bit of hex in the toolkit, about an inch & a half long - that's for the front axle. I use a set of those L shaped keys, as well as a set of the hex sockets.

For sockets & spanners, you should have at least these sizes - 8mm, 10, 13, 17, 19 & 24mm, the last for the rear axle nut & the alternator. A 30mm open end or ring can come in handy occasionally, too.

A half-way decent set of tools make life easier, and they don't have to cost an arm & a leg these days.

You can download relevant manuals from the MG 750 yahoo group & from "this old tractor".  Start on your collection. There is one excellent Breva owners manual that I have which is exceptionally clear & thorough, written in English, not translated. I'm sorry I have no record where it actually came from, but it is out there as a free download.

[sign216]

You can download relevant manuals from the MG 750 yahoo group & from "this old tractor". 

Join the Yahoo group, and then look at the Files page and the Links page for repair guides and shop manuals. 
It's best viewed on a computer, on in "desktop mode" on your mobile device. 

https://groups.yahoo.com/neo/groups/MG_750/info




And...if there's a problem I can help you log in to the group, but hold back on the messages re "Yahoo is evil" and "the govt is monitoring my computer" etc, etc.  Don't get me wrong, both are probably true, but I can't help w that part.