Lucky Phil

So finally got to the bottom of this gearbox housing crack. I'm down around 1.5 mm deep on a 3.5 mm thick case. Its a strange thing, something tells me it may be production related as opposed to consequential. No proof of this just a feeling in the water. Like the crack is generated during the casting cooling process. The area it originated from is the tightest casting corner I've ever seen. I dont think its from the squeeze of the mount bolt and in reality there is a front engine mount and the upper gearbox mount (that seems to crack) and the lower gearbox mount sharing what is a modest load in engineering terms. Seems well triangulated mounting to me and the thought that the cracking is limited to the green frame bikes without the additional lower frame to crankcase members is blown away as this is from a later bike as well. Hmmm, dont know. Next step is to see my friend the expert crankcase welder and machinist. Still there. ground out. Ciao

Yes good points, but I have 2 manuals from different eras with the same specs and the "5" stamped on the valve housing. Also applying the rule of thumb that's been around for 100 years and still holds true of approximately 10 psi/1000 rpm and with the high cam engines turning max rpm of 8400rpm then a 5 bar or 70psi relief valve sound about right. Also there's no guarantee with a relief valve that the original spring hasn't sagged so measuring its crack pressure wont necessarily give you a baseline. Ciao

The axle nuts are Probolt brand and I honestly cant remember what the sizes are, M20X1.5 or there abouts. I'll try and measure the size today if I can unless someone here beats me to it. They aren't cheap but on flebay you can find cheaper options in plain flanged hex style. Ciao

Oops, generally keep the chain and lock in the bedroom. Ciao

My Daytona and Centauro workshop manuals(both) give the oil pressure relief setting as 5 bar along with a 5 stamped on the valve housing. Ciao

True, I dont think there would be much more than a kilo or so to be save if you replaced every bolt with a ti one on a V11. I use them for their ability to stay looking nice forever. The weight saving is just icing on the cake. Here's the Titanium axle nuts I use on my bike. Next time I have the front wheel off I'll machine some thread off the front axle. Ciao

well after gaining some additional knowledge here on crack locations I went back and re checked my cases in the areas mentioned as problematical. The areas in question I had to strip paint from entirely as in the original images you can see some dye check finds I put down to residual paint but I wasnt really looking too hard in these locations as I thought the problem area was the lugs themselves. I wast too happy with what I found so went ahead and blended the step on the r/h side. A somewhat disappointing result I'm afraid as can be seen. I havent chased the crack all the way out so ultimately I dont know the depth as yet. Ciao

I think you can modify a 5 speed input hub fairly easily to 6 speed dimensions and they still make those probaby more economical way to go ciao

Hey Tinus89 can you re post here the images of your gearbox crack. The ones in the historical thread wont open anymore. I've seen LowRyter's l/h mount crack images so it looks like I've got some more reworking to do. Ciao

We'll find out once I can figure a way to actually get it off the bench:) Might need to enlist the help of a few 20 year olds I know. Ciao

Perish the thought Ciao

Yes docc, I'm running the extra plate. Ciao

A Dayton/Centauro and I would then assume an MGS-01 all run higher oil pressure than the V11 engine by virtue of its higher relief pressure setting. The Caruso oil pump has the potential to support pressure by virtue of its greater pumping volume. It also means that it can cover system losses better if things get to a dire stated internally for whatever reasons. A friend of mine had a relatively new MK4 Le mans years ago that would put the oil pressure light on in the summer at idle once warm running one particular grade of oil which I cant remember now. It was ok with 20W-50 under the same conditions though. I have always though that maybe the Guzzi engine is a little marginal with oil pressure at low rpm and high temps, Maybe. Ciao

Ok good to know. I didnt realize they cracked there as well. May need to do some blending there also or remove the whole corner as luhbo mentioned. Ciao