Breva 1100 Gearbox Replacement - AKA the Guzzi from hell

[Pescatore]

Impressive speed and good discipline for reading the manuals.
How's the swingarm bearing looking? Any grease in there?

[SemperVee]

 Brilliant!  Love a story with a happy ending!  Good on ya!

[BrevaIsTheName]

Thanks again y'all! It definitely isn't over yet, but good to know for sure. I'm still a little worried about that clutch rod bushing, but even if it isn't there, hopefully the input shaft is supported enough for it to be a non-issue when looking at "what connects where".

Yes, swingarm bearings looked pretty good actually! Likely because this old girl has barely been ridden. 20 years old and only 15,000 mi. I added a very generous helping of lithium grease and inspected the rollers which all looked good. Will be greasing the hell out of the CARC splines too when we get to that step-- maybe even today!

There was quite the mess of oil crud on the LH engine case, but the breather hose clamp wasn't even installed to the oil recovery tank, so I think that issue is/sorted. I will try and create a guide when all of this is said and done: the service manual is the best of any I've seen on previous bikes, but some steps need more detail. For example, unless you have very low-profile u-joints socket extensions (the kind that don't come from harbor-freight) it is virtually impossible to remove the clutch slave cylinder before the frame comes off and so working around the clutch line in an ergonomic nightmare. It's better to pull the line off from the master cylinder and thread it out of the frame-- this way you can also re-bleed the line and test the clutch before putting the whole thing together.

I have more to say but will do so later when I have pictures to provide intermission from the inarticulate word bombs I've been leaving thus far. If anyone has any insight into that bushing thing, do let me know!

[Huzo]

If I was stuck by the roadside, I’d like to have you with me. You have an indefatigable approach and a cheery good humour.
Bravo Sir…! 
Your Breva is fortunate to have you.

[DoubleGuzzi]

Doing all this outside, I can't decide on whether you're totally crazy! 
I hope that you give your Breva's smaller sibling plenty of lurve & attention - poor under-rated thing. It's not a "baby" it's a svelte small block, with mid-sized 750cc - the V35 is the baby!
Buy yerself a cheapo gazebo with zip up sides, for the bikes and it can even serve multi-purposes: beer tent, barbies etc.
 

[BrevaIsTheName]

It's been done! Everything buttoned up for now. I will have to come in next week and reinstall a new swingarm pin and castle nut, since the old threads were so chewed as to prevent the nut from screwing in all the way and providing preload. It's.. rideable as it stands, but I wouldn't take it on any trips until the new one gets here Thursday.

last night I went out for a celebratory photoshoot-- while I'm still painfully anxious (and will be for the next few hundred miles), but at least "La mia Brevonna" is still a hell of a girl to look at. (see pics below)

Resident CARC experts, is there anything I should watch out for when reassembling the rear driveline? I clicked the driveshaft into the front input shaft all the way, but the rear final drive just kind of slotted into place. It doesn't have a retaining clip in the rear, does it? And is it possible for the driveshaft not to be pushed in and aligned after buttoning the whole gearbox/swingarm/FD assembly into place? Just checking all my bases here. Seeing as this is the largest job I've ever done, I will be semi-shocked to find out I did everything correctly. Currently still sweating every tiny noise that comes from the bike, but so far the actual sound from the gearbox and shaft seem to be near zero.

On a related note, how many miles would y'all need to put on a repair such as this before feeling comfortable and trusting the bike again? Everything runs perfect after about a dozen miles so far, but I don't know if that is the calm before any sort of storm!











There are a few other things I will add after this post to any would-be shadetree mechanic attempting this job themselves, but for now I will collect my thoughts and relish in the simple beauty of this Moto Guzzi.

[guzzisteve]

The rear is assembled - driveshaft then swingarm then bolt on rear drive. Otherwise you can't get driveshaft clicked on to trans shaft while holding all that bulk & weight. Goes easier. 

Glad you got it- from another shadetree,  ride safe.

[BrevaIsTheName]

Thank you!! This is exactly what I did. Sounds like all bases are, hopefully, covered. Ride safe indeed. I'm just glad this awesome community exists :)

[BrevaIsTheName]

Okay, since I have a bit of time today I wanted to address some points that are either not mentioned in the service manual or may catch someone off-guard, should they attempt this repair on their own.

• When removing the clutch slave cylinder, ENSURE you have a push rod from the old gearbox or on hand, ordered as a separate part. The two rear bushings near the thrust washer stack come out, but the far (cylindrical) bushing is retained in the gearbox.
• The gearshift linkage is awkwardly held hanging until the side cover/rearsets are reinstalled. There is no direction specified for what angle it should be installed along the gearbox splines. Make a note of where yours was installed or prepare to adjust the linkage as necessary. A linkage installed at too low of an angle will catch the frame, making it feel like 1st gear won't engage and leaving only half shifts. Addressing this early will spare you the heart attack of thinking your brand new eBay transmission is faulty!
• The thick part of the cardan unit attaches to the input shaft of the gearbox. The yoke has a retaining clip which affixes it to the shaft. You will know it's installed correctly when you hear a click, but taking it out can be a pain. The only effective way to remove the shaft is to have a friend hit the part of the yoke closest to the gearbox with a hammer or mallet while you pull simultaneously. Make sure to grease liberally upon reinstallation.
• Take photos and pay attention to the original routing of vacuum and fuel lines. The bike was assembled very carefully with attention to this detail, so you must do the same.
• Since this is such a big job, I implore you to I-Mark everything. Use a paint marker to draw lines across fasteners and their mounting points. Use a torque wrench. Go slow. Write everything down. This CANNOT be done in an afternoon by your average joe, so don't count on your memory as it will fail you.

Having an organized workstation helps a lot-- stay organized, go slow and think like an engineer. Then you will be fine.

...unless this job catastrophically fails. In which case I will be back here with even more updates and a much, much more frantic warning!
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