Front forks and getting ready for chrome – 18 Jun 2014.

Front forks.

I’m chopping and changing a bit but I’ve now rebuilt the front forks. The fork springs on these old Guzzis are very soft so I’ve invested in some progressive rate springs to see if this improves things. They should still be compliant but less likely to bottom out than the originals. Guzzis use cartridge dampers in the front forks. Here are the parts that make up the arrangement.

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Shown is the damper (with the rod retracted), damper extension rod, spring seat, a locating cup and a circlip. You screw the extension rod onto the damper and fix it with the lock nut, pull the lot out to full length and drop on the spring. The instructions for fitting the springs show the tighter coils at the top (nearest the damper). I can’t see any reason why this should really matter but I did as I was told. You then need to get the spring seat and locating cup on and fit the circlip while the spring is compressed. Now you can do this by just pushing the spring down but it’s fiddly because you can also push the damper rod in at the same time. What I do is, once the spring is on, I compress it just a bit and poke a screwdriver in one of the holes in the damper extension rod. You can then turn the spring gradually putting more coils below the screwdriver, compressing the spring. This is enough to be able to fit everything.

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You can then get the spring seat and locating cap on with enough room to fit the circlip without having to fight the spring pressure.

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When you pull out the screwdriver and release the spring all the force will be on that circlip. Make sure you used a new one. 28p for two at the local engineering shop is a good investment. Just to be safe, I screw a bolt with a big washer into the bottom of the extension rod before I pull the screwdriver out. That way, if the circlip fails, you won’t be crawling around the workshop looking in dark corners for the bits that got fired off if the clip fails. It’s not been a problem with a new clip but once, reusing an old bent one that didn’t seat quite right, resulted in a search of the driveway when it shot out of the open garage door and I didn’t have another.

That’s the insides done.

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I changed the fork oil seals which are in the lower fork legs. They didn’t leak before but I’m using new fork stanchions as the old ones were well bent (and Guzzi stanchions are cheap) so replacement seemed sensible. I always have trouble getting these out. I blunted a little pry bar I have and forced some oil pipe over it and used that to lever the old seal out a little bit at a time and working round the seal. The hose protects the top of the fork leg when you lever on it but you do have to be careful not to damage the inside of the fork leg with the tip of the pry bar.

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The replacement seal must be driven in square. I start by gently knocking the seal into the top of the fork leg with a plastic mallet. Then I find a suitable socket from that 3/4 inch drive set that’s only ever used for bashing things and drive it home.

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I always drive the seal in as far as it will go. There is more space than you need because originally there were two ordinary seals fitted to each fork leg stacked on top of each other. For years replacements have been a special double-lipped seal which is better designed for the sliding action of the forks. I still fit the circlip inside the fork leg although it is nowhere near holding the later type fork seal.

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Next I unwrapped the new fork stanchion and fitted its top plug and new O-ring.

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Then I fitted the damper and spring assembly inside. The hex on the top of the damper mates with the inside of the cap. The special screw used to mount the instruments is fitted to hold the damper in place. I’ve got to make a couple of these screws as mine are bent and I can’t find any replacements. Luckily I have a friend with a lathe.

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Next I smear a bit of oil on the stanchion and fit it and the spring into the lower fork leg. In the picture, you can’t see it but, I have protected the fork leg before I clamped it in the vice!

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Once that’s gone in you should turn the stanchion until the little tab sticking out of the locating cap on the end of the spring matches a cutout inside the fork leg. The idea is that this will stop the internals turning when you put this screw and crush washer up through the base of the fork leg into the damper extension rod.

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However, I’ve never ever, even with a new locating cup, managed to get this to work. It doesn’t seem to matter as I have no problem doing up the bolt. Originally this bolt had a fibre washer to seal it. I use aluminium crush washers instead just because I know I won’t split it and get a leak. I do the same with the fork drain plug screws although here I temporarily used a fibre one as I’d run out. I’ll replace it soon. Again, a fibre washer will seal well enough but can split especially if you’re having to reuse it after changing the fork oil at some point.

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I did the other fork and fitted the dust covers.

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I shall probably change the covers for gaiters like I have on the S3. I know they’re not original and are a bit ugly but  they do protect the most important part of the stanchion from damage.

Prep for chroming.

If I don’t get some bits and pieces chromed soon it’s going to hinder progress but, before I can send stuff off, I need to do some preparation.

Firstly the horns. I bought some nice (expensive) Voxbell horns as per original when I put the bike back on the road over 10 years ago. They started to rust within a year. I could change them as originals are still available but I can’t see why I shouldn’t be able to rechrome them. So I drilled out the rivets, removed the grilles, and fitted a couple of nuts and bolts temporarily so that the lot doesn’t fall to bits when I’m not looking. I’ll refit the covers with stainless nuts and bolts. Here’s one grille removed and one to go. The horn still works.

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Next the handlebars. Now Rhino has “swan neck” clip on bars. For some reason, in all the time that I’ve owned him, the left had bar has been about an inch shorter than the right. The end of the bar was at a slight angle so I can only assume that it was damaged in an accident before I got him. It would have had to have been some slide though to wear that much away. I’d always managed before by just leaving a bit of handlebar grip overhanging the end of the bar. Not the whole inch but a bit. I decided to weld on a piece of tube to correct this and found that a damaged crashbar in one of my boxes of scrap parts would provide what I needed. I have a metal chop saw so cut the end of the bar square and chopped a bit out of the donor crashbar. I removed the chrome either side of  the join and beveled the edges then used my MIG welder to tack the two together, checked for straightness then completed the welds. I cut it to length and set to with files and emery cloth until I got this.

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It won’t matter if the weld shows a bit after chroming as, once again the grip will cover my repair.

I also dismantled the brake plates to remove the brake shoe cams. The cams have lost their chrome where they pass through the brake plates. One of the front brake shoes used to stick from time to time because of this so I’ll get them all done as well as the external linkages.

The locks for the two very distinctive V7Sport toolboxes are pitted. The replacements sold today would look more at home on a filing cabinet so I decided to take the originals apart. I used the excellent information on Gregory Benders site here http://www.thisoldtractor.com/moto_guzzi_loopframe_tool_box_lock_rebuild.html and measured all the little pins that came out and taped them in order to a bit of paper in the hope that I’ll be able to put everything back how it was eventually. Now I should be able to get the lock bodies and barrels rechromed.

And finally…

I’ve had all the brake shoes relined. Although you can still buy replacement shoes for a V7Sport, I spent similar money getting the originals relined. The original linings were very hard and it looked like they would probably never wear out although a couple were beginning to come adrift. Long life is nice but they were hard and used to go shiny. I would have to dismantle the brakes, roughen up the linings (not breathing in the asbestos) and go through the rigmarole of adjusting everything just to get a few weeks good braking. Then the performance would start all over again. I reasoned that, although the new brake shoes would be asbestos free, they were likely to be to a similar spec as the old.

I contacted a number of relining firms explaining what I wanted, the weight of the bike etc and asked for recommendations. A couple just said they’d use their usual materials which was no help, another quoted the lining they use on classic cars but one firm gave clear suggestions based on experience with other classic bikes. This firm Industrial Friction Materials Ltd, http://www.industrialfriction.com, are based in Cardiff and had been recommended. I took my brakes in and had a chat with the owner who showed me different linings and discussed their pros and cons. I was instructed to come back in 2 hours to collect the relined shoes. It was a sunny day so I went for lunch in Cardiff Bay and had an ice cream and a bit of a wander then rolled up in time for the shoes to come out of the bonding/curing oven. They were the most expensive of the companies I approached but seemed the most helpful and knowledgeable.

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For reference the front shoes were lined using Ferotec D3920, a molded lining. The rears lined with Ferotec 3806 which is a woven type. It will be a while before I can see if this is an improvement over the originals which were remarkably bad given the impressive spec and look of the brakes on the V7Sport.

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2 thoughts on “Front forks and getting ready for chrome – 18 Jun 2014.

  1. I like the polished fork lowers…I had mine powdered but I like what you have done with yours. Have you put oil in the forks yet? Any problems with doing that?

    1. I’ve done nothing to the fork lowers other than rub them over with Autosol. That’s their original finish. The forks on later bikes like my S3 are not so nicely made and painted. No oil in the forks yet. Not usually a problem getting it in. I undo the top screws that secure the internal damper a bit, push them down, then remove them completely. Oil can then be squirted down the holes and it will find its way to the bottom.

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