Wheel balancing, take 2 – 30 Jul 2016.

Having successfully balanced the wheels on The Fire Bike, I decided to go ahead and do the same for The Racing Rhino, my V7Sport. These weren’t balanced when the new tyres were fitted. A lot of what follows repeats stuff I’ve done before but I’ve got the time to set it out again!

I started with the front wheel which is the important one to balance. To get it off:

  • Put the bike on the centre stand.
  • Disconnect the front brake cables from the hubs by first loosening them at the brake lever end. This is to maintain the relative adjustment of each brake shoe.

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  • Slacken the wheel spindle nut and loosen the clamp bolts in the fork lowers.

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  • Jack up the bike under the sump so the front wheel is clear of the ground. I use the trolley jack I still have from my days of working on old cars.

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  • Remove the spindle nut and withdraw the spindle.
  • Lower the wheel to the ground complete with the brake hubs.
  • Make a note of which way round the wheel goes to maintain the direction of tyre rotation and to match the brake drums with their shoes.

The wheel and its spindle can now go in my home-made balancing stand.

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It was clear that the wheel did need some weights added so I gave the rim a clean then put it back in the stand. I marked the highest point of the rim and started to add weights with masking tape until the wheel was balanced. The wheel now stopped in a different place each time it was spun and would stay wherever it was put. It needed just 15g.

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The area the weights would be stuck to was cleaned with cellulose thinners and the weights fixed permanently. The rims on the V7Sport are Borrani Record “Cross”. This means they are more deeply valanced than those fitted to my V7 700 and means that there is room to stick the weights to the inside of the valanced part.

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The front wheel was refitted to the bike and the jack removed from under the engine.

Getting the back wheel out of the V7Sport is so much easier than doing the job on my loopframe V7. There are no panniers in the way and the rear mudguard hinges up so the wheel can be got out without the need to raise the bike or lean it on its side:

  • With the bike still on the centre stand.
  • Slacken and disconnect the brake cable from the brake hub.
  • Remove the brake torque arm.
  • Remove the wheel spindle nut.
  • Slacken the clamp bolt in the swing arm.
  • Undo the “thumb bolts” and raise the mudguard.

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  • Remove the wheel spindle while holding the wheel and brake plate in place against the drive box. Note that there is a thick spacer washer on the spindle¬† between the swing arm and brake hub.

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  • The wheel, together with the brake hub, can then be pulled off the drive splines on the bevel box, lowered to the ground and removed backward under the raised mudguard. Why aren’t more bikes fitted with hinged mudguards like this?

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The wheel was then cleaned and balanced in the same way as before. It took a lot of weights (as did the rear wheel on the V7 700).

I must have over-greased the drive splines on the wheel before. The grease had been flung around inside the hub on the drive side and some had found its way out between the wheel and the bevel box. I had begun to think that the big seal in the bevel box was failing again but, no it’s grease. It’s sticky and doesn’t smell like gear oil at all.

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I think the drive splines on the hub are showing some wear but are OK for now. I checked the spokes in this wheel, having had some loose ones in the past due to broken spoke nipples and couldn’t find any.

When it came to refitting the wheel, I cleaned the grease from the splines on the wheel and drive box then re-applied it but, more sparingly this time.

I haven’t added Oko sealant to the tyres on this bike yet ( as I did to The Fire Bike) but probably will do so soon.

5 Aug 2016 update: I have added the measured amount of Oko Puncture Safe to the tyres now.

  • Front 90/90-18 has 200ml.
  • Rear 100/90-18 has 225ml.

I went for a 10 mile test ride and got home after covering 80 miles.

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Home made wheel balancer and tyre sealants – 28 Jul 2016.

Ever since buying my V7 700 I have been concerned about getting a puncture, particularly in the rear wheel. I’ve been carrying a spare tube but know it would be near impossible to replace it at the side of the road by myself. To do so the back of the bike needs to be raised a lot to allow the wheel to come out. Alternatively the tank and fairing have to come off and the bike leant on its side and the wheel removed that way. That’s all before fighting to get the tyre off and back on again. Since damaging my wrist I’ve not had any success with tyre changing at all.

I’ve had variable results with “Finilec” type foam in an aerosol as a get me home measure in the past but decided I would try a tyre sealant this time. I realise that these puncture sealants are less reliable when used in tubed tyres but, if it doesn’t seal the hole, it should at least slow down the leak. I have had a tyre go down very quickly when traveling at motorway speeds and it’s not an experience I want to repeat. I will still carry the tube so a garage can change it if the worst happens and I have to call on my breakdown/recovery insurance.

I bought enough Oko Puncture Free to do both my bikes. The instructions say that the wheels must be properly balanced before adding the sealant. This is not just because the goo in the tyres will prevent you from balancing the wheel after. If the tyre is out of balance the sealant will make this worse.

I have roughly balanced wheels before by clamping the wheel spindle and letting the wheel rotate on its bearings. This is not a good way of doing things as the drag of the grease in the bearings doesn’t let the wheel move freely enough. I looked around the internet at home made balancers and came up with this.

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The two stands were made out of the wood I had in the workshop plus four skateboard bearings as recommended elsewhere on the web. I would have made the stand from metal but I had nothing suitable. I had to be accurate in getting the stands vertical and the two lots of bearings square to the stands and at the same height.

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I’ve still got my friends bike lift in my workshop while he’s building his garage so I used this with my wooden adapter plate to get sufficient height to get the back wheel out. I’ll do the front first.

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This is a remarkably steady arrangement and you’d have to be really clumsy to have the bike fall off sideways. I was more concerned that removing a wheel at one end could upset the balance forward or backwards. It turned out that I needn’t have worried but I stood my small lift under the back wheel when I worked at the front.

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So, front wheel off first.

  • Disconnect front brake cable at hub.
  • I had to remove the sender for my additional push-bike speedometer.
  • Remove large axle nut and loosen the clamp bolts at the bottom of each fork leg.
  • Pull out the wheel spindle and lower the wheel and brake plate to the ground. It made me jump when the cover from the other side dropped on the floor with a clang. It always does that!

There is a washer on the spindle between the left hand fork leg and the brake hub.

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Once the wheel was out I put it in my wheel balancer with its spindle.

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I should have taken some pictures. The spindle turns very freely on the skateboard bearings. I spun the wheel a few times and it came to rest in a different place each time. It would also “stay put” in any position I put it. When the tyres were changed last year I was told the front had been balanced by removing half the weights that were originally on it. It seems that was true so the wheel was left as it was and refitted to the bike, retracing the steps taken to remove it.

Time to get the rear wheel off.

  • I removed the left pannier from the rack for access although I probably could have managed without doing so.
  • Remove nut and lock washer from brake torque rod at the brake hub and loosen the fixing at the swing arm end of the rod.
  • Disconnect the brake pull rod from the lever on the hub. I like to tie it to the rear shock-absorber.
  • Remove the big wheel spindle nut.
  • Loosen the spindle clamp bolt in the swing arm.
  • The torque rod can now be pulled off the brake hub.
  • I use a big bolt through the hole in the wheel spindle to turn it forwards and back while pulling it out. At the same time I hold the brake hub and wheel in place on the rear drive bevel box.

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Once again there is a washer on the left side of the spindle between the swing arm and the brake hub.

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  • Pull the wheel and brake hub together off the splines on the drive box and lower it to the floor.

The wheel was mounted in my wheel balancer which had now been modified by screwing the two halves to a large block of wood. It made things steadier and keeps the spindle in line better.

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This wheel was not balanced and I could tell just by spinning it. I could feel the heavy part going round! The trouble was that the rim was too dirty to stick weights to and I would have to clean it first. Cleaning valanced Borrani rims has been one of my least favourite jobs. However, I think that may be a thing of the past! I used “Elbow Grease” and my “Sonic Scrubber” I bought from Aldi last year. The Elbow Grease is cheap and was recommended for the job by another owner of old Guzzis.

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It got the rim clean and I could have gone on to polish it with Solvol or something but, not on this bike. The wheel was put back in the balancer and weights were added to the rim, temporarily with masking tape, opposite the heavy spot until I was happy. It took a lot of weights. I was using stick on weights and, due to the rim profile, only 5 gram ones will fit. I used 11¬Ĺ (57.5g) of these and the wheel balanced perfectly. I cleaned the area with thinners then fitted the weights properly.

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I could have used spoke weights but, these are expensive and I didn’t know what sizes to buy. I think I’ll get some of these next time.

The wheel was refitted after re-greasing the drive splines then the brakes were reconnected and adjusted. I left the pannier off for the moment.

The whole purpose of the exercise was to be able to add sealant to the bikes’ tyres. The Oko web site gives the amount to put in each tyre.

  • Rear, 4.00×18 – 225ml.
  • Front, 100/90×18 – 225ml.

The bottles hold 500ml and are not marked that accurately . I used a syringe and some tubing cut from the Oko bottle. Getting the sealant in was easy.

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  • Turn the wheel till the valve is at 4 o’clock and remove the valve core.
  • Add the measured amount.
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  • Blow the valve clear with compressed air and refit the valve core.
  • Inflate the tyre to the correct pressure.

I think I got the amounts right as I reckon there was 50ml left in the bottle.

The pannier was fitted to the bike which was then lowered to the floor.

I went for a short run on the bike. The instructions say to go gently for the first 4Km to distribute the sealant in the tyre. All felt good so I took the bike up to speed. The sealant had no adverse effect on the feel or handling of the bike that I could tell. However, I’m not a “riding god” and just ride what I’ve got!

Gearbox clutch-shaft oil seal replacement – 13 Jul 2016.

Having got access to the gearbox, it was now time to tackle the leak from its front end. Just to backtrack a little, before removing the gearbox I like to tie the clutch arm on the ‘box so it can’t swing about and get damaged. It also means the return spring can’t get lost either.

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Once the nuts have been removed the gearbox can be pulled back off the engine. It needs to be pulled back squarely.

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I transferred the gearbox to the workbench to take a look at what I’d got. It was clear where the leak was coming from. As I’d expected, the oil seal around the input (or clutch) shaft had failed. You can see where the oil has run down the front of the ‘box.

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Luckily there is no sign of any oil getting to the clutch. If this seal fails or the rear crank seal fails on the engine you are usually (but not always) OK as the clutch itself is housed inside the flywheel away from the oil.

To reach the oil seal I had to remove the clutch hub which is held in place by a peg nut and a star lock washer. These can be problematic. The first thing to do is to find which slot in the nut has got a tag from the washer folded into it.

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I abused a small screwdriver to start levering the tag clear. Then used a punch with a flat end to knock it back out of the way.

To undo the peg nut holding the splined hub you ideally need three Guzzi special tools. The first is a bracket you bolt the gearbox to so that it can’t move about. The second is a tool to fit the splines of the hub and hold it still (I keep meaning to pick up a worn out clutch plate to make one from). Finally you need a four-pronged socket to fit the hub nut.

Years ago I made a special socket by grinding a 30mm socket. It’s ugly but it works. To hold the hub nut still I used some rubber on the splines and a set of stilsons which are equally nasty.

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The hub then just slides off the splined shaft. The back of the peg nut which goes against the hub is curved as is the lock washer. This is so you can reach a tag to bend it forward. Both nut and lock washer were in good condition so I could reuse them.

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It seems that when I fitted the gearbox I broke one of my own rules. I would say that it’s worth replacing this seal whenever you have the box off because it takes so much work to reach it. However, I can see that this is still an old seal and, what is worse, I replaced the clutch hub and still left the old seal in place. This was just asking for trouble!

I also recognised some old damage I’d forgotten about. It’s very old (1970s), from before I owned the bike and is to the part of the gearbox where the seal fits. I don’t know what could have caused the wear but something appears to have let go in the clutch housing at some time. The oil seal itself has been rubbed as well.

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I tried to get the old oil seal out by putting a self-tapping screw in it and levering on it but the screw just pulled out.

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However it weakened the seal enough to be able to put a small screwdriver in the hole and lever it out that way. I noticed there is some damage to the face where the seal sits. It looks like a little triangle. I think it should be fine and won’t cause any problems. In the photo it looks neat enough to be supposed to be there.

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That wear to the “boss” on the front of the gearbox caused me a bit of a problem. Normally you would knock the new oil seal in until it is level with the surface. However the surface is now crooked. I measured the depth of the housing to the outer race of the bearing with my calipers.

9.87mm at 12 o’clock.
9.74mm at 3 o’clock.
10.17mm at 6 o’clock.
9.64mm at 9 o’clock.

I made a mistake with my first attempt. I set the seal in square but too deep so that it was partially recessed. Of course it was ruined taking it back out again. I had bought two seals which was lucky. The second time I carefully tapped the seal in until it was flush at the 6 o’clock position. This meant the seal was standing a little proud elsewhere but it was secure. To check that it was actually in square, I held a small steel rule across its face and slid the clutch hub onto the splined shaft to check the back of that was also flat on the rule. I tested it at different angles and I had got it right.

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When I oiled and slid the clutch hub partially into the seal I could see that the witness mark from the old seal also lined up well. The hub was pushed on properly and the locking washer inserted. It locates in a slot in the shaft.

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That peg nut was tightened by hand then some means was needed to lock the hub again. I didn’t resort to the stilsons this time. Instead I used a piece of wood and a small scrap of metal to jam the splines.

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I can’t find any torque figure for this nut so just did it up as tight as I could manage and then bent a tab of the lock washer forward.

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I had intended to change the oil seal at the output end of the gearbox as well while I had it on the bench. They are both the same and is why I had bought two seals but, now I haven’t got one spare. There was no sign of any leak from the back of the ‘box so I decided to refit it as it was. At least if this seal fails it can be reached just by taking the wheel and swing arm off rather than having to dismantle the whole bike or crab the frame.

Before refitting the gearbox I remove the rubber blanking plug that you use when timing the engine, from the side of the gearbox. You also need to have a long-handled screwdriver handy. I get the ‘box on the mounting studs and, if the clutch hub doesn’t slide into the driven plates I can turn the hub a touch with the screwdriver through the hole until it goes together. I find that easier than having the ‘box in gear and turning the output shaft.

Un-crabbing the frame!

This is basically the reverse of the dismantling process (but you might swear in different places). There are a few things to remember;

  • Leave the final tightening of the frame/footrest bracket bolts, front and rear engine bolts, the lower crashbar mountings, and the screws holding the plate under the battery to the gearbox until they are all in place and screwed home.
  • Adjust the swing arm bearings so there is no slack but they do not bind. The pins should project from the frame by the same amount on each side (7.1mm both sides in my case) before fitting the lock nuts.
  • Take the opportunity to grease the splines on the back of the gearbox, the driveshaft, its sleeve and the bevel box as you refit them.
  • Leave the final tightening of the four nuts holding the bevel box to the swing arm until after you’ve got the rear wheel in and the axle tightened. this is to make sure the axle is properly aligned and can be removed and inserted easily.
  • Grease the splines between the rear wheel and drive box.
  • Also grease the bushes that hold the gearchange crossover shaft in the lower frame rails.
  • Adjust the rear brake cable.
  • Adjust the front brake cables at the lever to keep the two front brake drums synchronised.

The reassembly took a little longer than the dismantling because I spent some time cleaning the exhaust system and putting it together with silicone sealant. My experiment with this was a success so I’ve done it again. The only problem is that you have to leave the exhaust and sealant for 24 hours before running the engine.

Result!

As it happened it was two days before I could get back to working on the bike. Today I removed it from the bench and re-did the carb synchronising just in case! There was no gear oil leak and this afternoon I went for a quick 50 mile ride. All seems fine.

Before going out I had removed some of the blueing from the exhaust header. I don’t use commercial chrome cleaners usually as they can damage/remove the chrome surface. However I tried a little this time. I didn’t try to get rid of all the discolouration but just reduced it. The blueing didn’t reappear during the ride but I’ll just have to see how it goes.

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