So, with the bike reassembled and the project goal accomplished, I've had the opportunity to put about 250 miles on the 850T. A few things quickly became apparent, as one might imagine; nothing unusual or troubling, just the routine experiences and observations which come from daily living with such a mechanical entity. While I can live with it just fine as is, a little attention to the following will enhance the reliability and rideability. The forks are quite undersprung and the front disc brake is very poor, like a block of wood against steel. I also found a small leak at the base of the right cylinder and the rear drive leaks as well (minor leaks are a major reason for maintaining a clean bike so, first, you are aware of a potential problem very early and, second, you can more quickly pinpoint the source). Minor issues are par for the course on a 40 year old bike - note, I do not expect it to handle like any of the other decades-newer bikes in my stable. Nonetheless, these are correctable, and things that I'd like to sort out.
The first thing is getting the cylinder leaks taken care of (leaving tiny, misted droplets on my boots after a 30 mile ride). Some brief research implies that this is normal for big block Guzzi's, and should be rectified by re-torquing the cylinder heads. After sorting through various forum exchanges I determined that the torque needs to be at least 32 lb/ft and no more than 34. Unfortunately I only have a torque wrench in inch pounds, which tops out at only 3/4 of this range. Oh well. Pictured below are the rockers under the valve cover over the left side cylinder. Another 'unfortunately', the rockers have to come off for access to two of the six bolts holding the cylinder head down. It was not difficult or all that time-consuming, but I had put it off for a few weeks as the first time doing anything carries with it a little trepidation. I could feel that the six bolts loosened fairly easily (not easy, just easily enough) - judging that they needed more torque and not having a torque wrench, I simply marked each bolt with a tiny scratch so I could confirm that it had been snugged a tad (technical unit of measure) more than before. All buttoned up again, the left side is ok but the right still has a little pool of oil collecting on the lower inside. I've since borrowed a larger torque wrench to get to this job again shortly. Ugh.
The next thing to warrant attention are the fork springs, since I'd like to correct the saggy feel and dive before addressing the disc brake. I'd removed and serviced the forks during the rebuild, and put the stock springs back in; whether they ever were in the first place, they are not quite up to the task now. I called Progressive earlier in 2016 looking for springs with a heavier spring rate for this bike. I purchased the recommended springs (0.68 kg/mm) but they were 60mm too long. Or at least they were 60mm longer than the stock springs and I was sure that they could not be compressed enough to fit. Past 90 days from purchase I could not return them, but the tech told me they could be cut down a few inches. Consulting Guzziology, it was noted that a spring should generally not be much more than 1.5 inches above the top of the damper shaft at full extension (or spacer length if setting preload). The stock springs sit at exactly the top of the shaft when not compressed. Feeling that the Progressive springs would be stiffer than stock, I elected to cut the Progressives down leaving about 1.5 inches. This was a mistake! Whether they are stiffer than stock or not, I still cannot really say. The sag is better and they are compliant and not springy, they still sag several inches under bike and rider weight and then bottom out under heavy braking.
To Resolve - the cut piece can actually be used as a spacer; either with the stock spring or the Progressive. Although the total length of the Progressive spring may be prohibitively long..... I just hate to take these on and off in a trial-and-error fashion. But I cannot identify what the spring rate of the stock spring is.... Ideally, for a bike weighing about 500lbs and a rider (me) weighing about 200lbs, a spring rate of 0.95kg/mm is called for.
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| above = stock spring (420mm); below = Progressive after cut (total 480mm) |
And last, the seat. I somehow knew that this saga would end with me actually fabricating a seat for myself. After the shop which made the first cafe seat (too low and interferes with rear fender) promised to replace it, and then waiting another 2+ months, they won't do it. Options include buying a stock seat just for the pan, or using the cafe pan I have. I can't use the seat that came on my project as it is not original and was fabricated from aluminum, thus it doesn't hold its shape well and presents problems for attaching the seat cover. So cannibalizing my new cafe seat for the pan will be my approach. I also think I can cut off the top of the foam to retain the shape of the cafe seat, as they did quite a good job of this (and it requires patience and skill, two things I have only in limited supply).
Two dense foam pads from Home Depot (gardening kneelers) will serve as the base on top of the pan. Then the cafe padding, then I bought a roll of 1/2" foam to cover and smooth the underlying layers. From eBay, I found a Moto Guzzi V7 replica seat cover that has the words 'MOTO GUZZI' in block letters across the back. The hump is not the same, but close enough that I'm confident that it will fit (and still look "cafe") with a little tuck here and there and extra foam if necessary.
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| slightly photoshopped to show where it would sit higher after modification |
