A screw loose – 10 Jul 2015.

Preparing to go out on The-Big-Red-One I noticed that the distributor cap was loose. It seems one of the little screws that holds a clip for the cap had successfully made a bid for freedom! There was no sign of them in the garage or on the driveway so an M4 screw, lock nut and cable tie were used as a temporary measure.

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I checked all the usual sources in Europe and, while I can get the clip from any number of places (including classic Fiat 500/126 part specialists), I can’t get the special screw as well. I turned to Harpers in the US who have them listed as being in stock and ordered two of each so I’ll have spares.

Drum brake adjustment and cable fitting – 08 Jul 2015.

Hello folks, I’m back! Computer troubles have been sorted with a new hard drive and it’s time to catch up, although one or two photos were lost. The tank, seat and rear mudguard I had trial fitted have been removed and put back into storage.

I decided to fit the brake cables (I seemed to always be moving them to get at other stuff) but, first I had to put together the levers and fit them to the bars. The lever “perches” have been rechromed as have the pivot screws. The brake lever blade is a new one while the clutch side is still the original. It had some deep scratches in it so I had a go and removing the worst of these. I couldn’t get rid of them completely though. The brake adjuster is mainly rechromed parts but I made a replacement central piece out of stainless. It’s the part the two knurled adjusters turn on and mounts the cross bar for the two cable ends.

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Front 4-shoe brake.

I haven’t got any photos of the adjustment procedure for the front brakes and it’s all a bit complicated. However, I’ll try to describe the way I’ve always done it.

The front brake is made up of two separate twin leading shoe drum brakes – one on each side of the wheel. Each of these needs to be properly adjusted then matched to the other side. It takes some work to get them “spot on” but makes all the difference between excellent (for its day) and marginal (possibly frightening) brake performance.

I start with the left side front brake and remove the tie rod joining the two brake arms on the brake hub. The left cable is the plain one while the right one has the brake light switch fitted. I fit the cable and ensure that, when the brake shoe contacts the drum the angle between the cable and the lever is close to 90°. It will be more acute when the brake is released but 90° or just under when the shoe makes contact. This angle should result in the most efficient leverage and you need all you can get. If it’s not right try moving the lever round one spline on the hub to get it closer.

I adjust the cable so that the brake just drags when the wheel is turned. Now I push the other lever on the hub so that it increases the drag on the wheel. You’re trying to double the amount of drag. Check that the lever is roughly parallel to the one with the cable and, if not, move it on its splines. Adjust the length of the tie rod by turning the end with the lock nut and refit it to the levers with the clevis pins. I then check the drag again. If all is ok the split pins can be fitted to keep the clevis pins from dropping out. Slacken off the cable adjuster so the wheel will spin freely and that’s the first side done.

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Repeat the process on the other side. I couldn’t quite get the angle of pull that I wanted. This was the best I could manage.

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You now need to synchronise the brakes on either side of the hub by balancing the pull on the cables. I make as much of the adjustment as I can at the wheel end of the cables but put one or two turns on the adjuster at the hand lever first. Going back to the left side I adjust the cable so the brake drags again. Then I slacken it off just enough for the wheel to turn freely while counting the number of flats turned on the adjuster. I turn my attention to the right hand brake and tighten the cable till the brake drags by roughly the same amount as the left one did. Next I release the cable again to check the brake will free off in the same number of turns. It usually does thank goodness! Now I do up the adjusters on both sides by the number of flats I counted and check that the wheel is harder to turn. The cable adjusters are then backed off equally on each side until the wheel will turn and the lock nuts done up. Fine adjustments can then be made at the handlebar end which won’t ruin the balance.

It’s a proper palaver but has to be done regularly (but you get quicker with practice). It’s not like a bike with hydraulic disc brakes which are basically self adjusting. I shall have to redo the adjustment as I haven’t fitted the rubber covers on the cables at the lever.

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Rear brake.

This is another twin leading shoe affair operated by cable and pedal on the left side of the bike. It’s adjusted in the same way as one side of the front brake. All those leading shoes give the best brakes possible when going forwards but make it tough holding the bike if you have to stop on a hill!

I had a problem. The cable supplied as a replacement for the rusty original would not allow me to get a good brake pull angle between the lever on the brake plate and the cable.

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This was because the cable adjuster at the wheel end was too short. The original long adjuster is needed to physically get the cable on with the lever positioned on the splines properly. In addition the new cable was slightly too long to fit properly.

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I decided I would take old and new cables to Speedy Cables in the Swansea Valley and ask them to alter the new one so it matched the original. While I was about it, I left the speedo and tach with them for a repair quote. As always the result was perfect. Here you can see the old and remade new cable and the incorrect adjuster. As you can see, it includes a brake light switch.

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The correct angle for the brake lever on the drum could now be achieved. The adjustment at the front end of the cable is to alter the pedal position.

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Clutch cable.

After all that, the clutch cable was much easier to fit and adjust. I got Speedy Cables to make this from the spec given in “Guzziology” as the last one I bought bore no resemblance to what was needed and I haven’t got one to copy. Clutch adjustment is made at three places – either end of the cable and by moving the adjuster in the arm which acts on the pushrod in the gearbox cover. This should be dealt with first to give the correct angle of attack so that the clutch will disengage properly. Then the cable is adjusted to give the (essential) amount of free play.

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I’ve done more so will be back again soon to tell you all about it.