Bell Housing Leak

[moto fugazzi]

Ken,

 

Be sure to have your dealer address the other leak sources while the bike's apart: the cam plug and the two bolts. Some would say it's also a good time for a new gearbox input shaft seal and a new seal for the clutch actuation shaft.

 

Thanks for posting your results. This remains on my "To Do" list . . .

I'll have him address the cam plug as well. When I stopped in today, he also showed me that he replaced the tranny input shaft seal and the clutch actuation shaft seal. Part of what was taking so long was the extra seals he had to order once he had the bike apart. This dealer is mostly a high end Italian used car dealer (Ferrari, Maserati, etc.), and he has been building race car engines since the 70's when he moved here from Italy. They started selling Vespas and MG's in 2009. 

Ken

[docc]

Sounds like you're in good hands!

[moto fugazzi]

Finally got my bike back yesterday. Quite a few setbacks from the dealer-wrong parts ordered or sent, plus a few medical issues with the mechanic (got some metal debris in his eye, then he had some outpatient surgery done for something else a week or so later).

 

Anyway, all of the leaks are fixed, plus I have new clutch plates, shift return spring, swing arm and wheel bearings, and all new tranny seals. The dealer also took off the aftermarket foot controls and replaced them with the stock units, and the bike has never shifted this smoothly. Ever.

 

The ironic part is that I dropped it off in December of last year since it's too cold in WI to fix it during winter, and I was promised the bike would be done in March. Had I known it would take this long, I could have done it in spring, and saved a bunch of money. At least it gave me time to modify my V7C by taking off the spoked wheels and replacing them with Breva 750 cast wheels and putting on the racer exhaust and adding new hanging brackets.

Ken

[docc]

With my recent clutch failure, the time has come to address oil leaks between the back of the engine and front of the gearbox. Quite obviously, I've been putting this off for a good long time . . . yet, a *dry* clutch should be dryer than the driest wine. Dry like the 'dry heat' of Arizona. Or The Sahara. Dry as moon dust. Mine looks more like a Chimichanga.

 

I understand the two seals at the gearbox front (main seal and push-rod seal), and the engine rear main seal. I appreciate Pete's advice that the lowest two bolts on the rear of the engine should be thread sealed. And the cam bung to be sealed as well.

 

The gasket under the crankcase vent should be no problem at all: (P.42/#15 - 12 00 7600)

 

What about the simple gasket (P.31/#39) under the "Complete Flange" (P.31/#40 - 12 01 1400) Can that be easily renewed? [it appears to cradle the rear main crank bearing?] 

[Tinus89]

What about the simple gasket (P.31/#39) under the "Complete Flange" (P.31/#40 - 12 01 1400) Can that be easily renewed? [it appears to cradle the rear main crank bearing?] 

 

If you refer to Page 31 pos 40, main bearing gasket: yes, very easily. I replaced mine when I had the engine apart, it's just a paper gasket like any other. Give the mating surfaces a good clean and you're ready to go. Indeed, to not forget to seal the bottom two bolts.

[Chuck]

It's easy to replace if you don't break the flange taking the bearing carrier out.   I've never had a problem, but I've read of people that have. Two of the holes are tapped, and you can either use a puller or a couple of jack screws to slowly jack it out. In the worst case, a guy can use the crankshaft to force it out in a press. 

[docc]

This looks like the primary culprit:

[andy york]

looks like you gonna need some more of my tools

no hammers allowed

                                        

[luhbo]

The gasket of the main bearing sees the full oilpressure, so work carefully when you decide to pull the shield.

[docc]

(Both bottom flange bolts also quite wet.)

[gstallons]

Any fastener that goes into a open hole should have thread sealant on the threads . Blind hole fasteners do not need sealant . When you do supply sealant , the bolt should be completely clean and free from any oil . Same goes for the hole threads .

[docc]

Any fastener that goes into a open hole should have thread sealant on the threads . Blind hole fasteners do not need sealant . When you do supply sealant , the bolt should be completely clean and free from any oil . Same goes for the hole threads .

Good method.    The Workshop Manual does state to "apply teflon tape on the two lower fastening screws."

 

There was a little brown gunk left on them when I took them out, but no longer sealing. Appeared to be olive oil based.

[68C]

Looks like a bonded seal washer would help here, you know, a washer with an o'ring bonded inside it. Also known as a Dowty Seal.

[docc]

Like this ?

 

https://www.mcmaster.com/#standard-washers/=18o1h17

[68C]

Looks like one to me.

 

The clever part is how they seal, it does not really seal around the shank of the bolt so does not matter if on the threaded portion. Any leak will pressurise the seal outwards/radially this will make it thicker and so press tighter on the flange and the underside of the bolt head. The higher the oil pressure, the tighter the sealing action. Obviously the flange needs to be flat.