Well having fought two other motors to a standstill, its now time to look at the motor that came with my bike. This has an obvious oil leakage from behind the magneto so the oil seal there at least is gone. I want to renew all the gaskets and seals and obviously whilst doing this its sensible to change the bearings and any bushes as appropriate.
I'm going to take this fairly quickly as a more detailed description of a strip down has been given already- this is mainly to present and organise my pictures so I can use them as a record in case needed.
Firstly remove the chain sprocket using the puller
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| Sprocket extractor |
Remove the cylinder head, 4 nuts and washer
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| Removing the head |
... and pull up the cylinder block
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| Pulling off the barrel |
releasing the piston.
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| Barrel off |
I numbered the bolts from 1-8 clockwise around the motor starting at the bolt lying at the rear cylinder block stud as number 1- shown here.
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| Numbering the bolts, no 1 id top centre of photograph, numbering proceeds clockwise. |
I stored the bolts in order using a cardboard strip- in case interested, in this motor at least the bolts have the following lengths (I'm assuming that the bolts were in the right holes to begin with!).
1: 80mm
2: 55mm
3: 80mm
4: 80mm
5: 80mm
6: 55mm
7: 72mm
8: 80mm
Bolts 2 and 6 enter the steel case inserts and in my view really need to be 65mm
Crankcase through bolt 50mm
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| Bolts stored in order |
I removed the brake lever and its circlip (not shown) but left the inner circlip securing the pedal driver to the case and removed the case by tapping it with a rubber mallet. Unlike my other motors this one separated relatively easily.
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| Removing the lhs case |
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| LHS case removed, clutch cup and 80t gear revealed. |
Remove the "Omega" clip at the bottom of the clutch cup- press down and inward.
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| Tab of omega clip visible in notch, press in and down with a screwdriver. |
remove the clip and..
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| Clip removed |
... pull off the clutch cup
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| Remove the clutch cup- it just pulls off. |
Note the shim on top of the 80t mainshaft gear (don't lose it)
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| 80t gear shim |
Remove the clutch by compressing with the special bracket using case bolts 1 and 3- do not over compress or you will cause the clutch to slip in the next stage.
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| Fitting the clutch compressor, use bolts 1 and 3 |
Fit the gear locking tool (home made in my case) to lock the 80t gear using bolt no 4 and an 8mm bolt through the engine mounting hole. Not shown here- see previous rebuild post.
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| My home made clutch locking tool. |
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| Clutch locker in use (old picture) |
Unscrew the clutch nut abd take off the two spring washers. Remove the clutch release mechanism
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| Clutch release mechanism, spring ends (bearing on lower) and spring. |
Turing to the other side of the motor, remove the circlip and washer from the end of the gearchange pushrod so that the change lever is disconnected.
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| Gear change lever secured to shift rod |
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| Close up, E clip and washer |
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| E clip and washer removed |
On the lhs of the motor the 80t gear should just slip off. in this case it was unusually stiff, you may need to push it down and twist to release the gears . It helps if the motor is in neutral and I suspect this one was somehow tangled with the gear change dogs. I made a mental note to inspect the gear change system later.
Removing the 80t double dogged gear.
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| continued |
Removing this gear usually leaves the main shaft in position- in my case it seemed to fall out of its bearing inside the case, the gear and dog fell loose and the bush separated from the gear. I couldn't remove all these parts until I had further separated the cases.
I went on to remove the clutch centre- the cover just lifted off.
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| Clutch basket |
The clutch turned out to be a five plate unit- probably because this was the higher powered higher compression later motor
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| Basket removed- 5 plate clutch. |
The clutch centre is held on by its circlip.
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| Clutch centre, held by circlip onto crankshaft |
I removed the circlip with circlip pliers.
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| Removing circlip, note that mainshaft is in position but seems to be loose and is drooping down. It fell out completely moments later |
Once the circlip was removed the clutch centre should slide off although it may need levering. In this case it simply lifted off with a gentle hand pull.
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| Clutch centre |
There should be an O ring below the clutch- at this stage I couldn't see it so I continued with the strip (found it later).
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| clutch centre removed |
At this stage I turned the motor over to remove the centre to rhs case bolt and nut. As I turned the motor the main shaft simply fell out of its bearing - this hasn't happened before. I unscrewed and removed the short centre to rhs case bolt and its associated lock washers.
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| Crankcase internal bolt |
Note the main shaft became loose and dropped out as I turned the cases to work on the other side. To remove this I needed to split the remaining two cases.
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| 80t gear removed, mainshaft has fallen out. |
To my surprise a gentle tap was all that was needed to start the cases separating - it should have taken more than that so I suspect this joint hadn't been gas tight either!
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| Cases beginning to separate |
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| ...and still separating.. |
I could now remove the main shaft, the gears on it just fell off. It seemed to me that it had been jammed on the gear change fork which looked a bit worn, I will need to compare this with those from other motors.
Once the centre case was removed the lay shaft double gear unit could be lifted off its shaft, note the shim on top of this gear unit and once again there was no shim below even though the manual shows one in this position. I now know better than to try and replace it!
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| Layshaft double gear column- shim from the top, no shim beneath. |
The crank shaft also lifted out-much more easily than in previous motors. I did find the clutch O ring on the crank shaft just below the splined section. This was in very poor condition, brittle and marked from the splines.
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| Found it! The clutch O ring wasn't missing but hard and flattened in the groove on the crankshaft below the splines. |
The pedal shaft lifted out easily
The circlip and thrust washer were removed from the gear change push rod so that the fork can be lifted off. Note that the parts book shows only a circlip in this position but in every motor I have stripped I have also found a flat washer mimicking the attachment system on the gear change lever side.
The gear change fork should slide off although in my case the shaft was a little burred and the fork didn't come off easily. I wondered if this had meant that the gear change was unusually stiff and I'll investigate polishing to improve the slide. If this doesn't work I'll need to replace some of these components; rod, bush or fork.
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| Washer and circlip from gearchange rod |
I tapped out the main bearing from the rhs case, The oil seal in this position had simply fallen apart and this explains why the motor had leaked in this position.
At this stage I cleaned all the cases, removing old gasket and gritty grease deposits. I could then tap out all oil seals and bearings.
More of a surprise was that the crankshaft oil seal mounting hole below the magneto was slightly out of round and cracked top and bottom. This could have been the cause of the seal failure. I may have to replace this case, but as this is the case with the engine number stamped on it, any swap would
obviously change the originality so I'd like to keep it if at all possible.
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| Oops this opening and oil seal mounting hole is distorted and cracked. The broken seal has been removed. |
I managed to restore the roundness using a socket which was exactly the same size as the seal, tapping this through a few times restored a nice rounded profile. I will use some jointing compound when I replace the seal to try and block and leakage along the cracks and hold the seal in place. Hopefully it will not be significantly off centre
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| Socket fitted perfectly, tapping it through to restore shape |
o
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| Finished, socket moves easily through with even gaps |
I also needed to replace the pushrod oil seal. In this case I didn't have a new manufacturer's seal so I removed the gear change lever by knocking back the positions where the case had been peened over the pivot rod
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| Gearchange rod oil seal removed- visible below the fork |
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| Knocking back the peening that holds the fork pivot rod prior to removing the fork |
I could then line up a drill and use a flat-end mill to mill the hole out to 14mm.
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| Oil seal hole milled out to 14mm using a flat end mill |
I could then fit a normal (non metal cased) seal 14x6x3 and refit the gear change pivot.
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| 14x6x3 oil seal inserted |
Changing the bearings and oil seals in the other cases was straight forward and proceeded as described previously, except that two bearings (mainshaft and rhs crank shaft) were just too loose and fell out again even with mild heat. They would certainly not stay in position in use so I secured them using Loctite 620 heat resistant retaining compound. I polished the gear change rod and re-reamed its bush to 6mm. This ensured that the rod could slide easily through the bush and the fork slide easily along the rod. I honed the I side of the clutch turret and pedal shaft exit on the clutch side crankcase as both were scored and had been leaking.
I removed the 4 O rings from the driver unit, 2 large external and 2 smaller internal. Simple matter to replace.
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| Brake pedal driver and o rings removed |
Use plenty of oil and insert the driver into the clutch side crankcase and secure with the inner circlip. The unit is stiff to turn with new O rings but I. Hoping it will ease up with use. Ive found that its easier to fit the case if this brake driver unit is fixed in the case and cant slide inwards along the pedal shaft. Use plenty of grease on the pedal shaft, use the special insert wedge if you have it.
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| Driver inserted to lhs case and retained with circlip |
I replaced the clutch cup O ring. Opinion is divided as the old rings seem to be a better fit, but in this case the seal had clearly been leaking so I replaced it.
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| Clutch cup, old O ring top, new bottom. Different sizes |
I removed the clutch bearing using two sockets. A 30mm socket fits over the spring base to press (just) on the outer race of the bearing. A 6mm socket on the other side fits inside the bearing to press on the spring base. Using a vice I could press the spring base out of the bearing and into the larger socket.
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| How remove the clutch bearing- spring base emerging from the bearing and fits inside the 30mm socket. Extraction shown mid-way. |
Use an appropriately sized socket to press the new bearing onto the spring base, press only on the inner race.
The layshaft bottom dogged gear slipped off the shaft and the bush fell out if it. I was concerned that this shaft may be worn but measurement showed it has a diameter of 11.96mm all the way along. This doesn't seem to be much wear so I will reuse it even though it seems a loose fit in the case bearing. The new dogged gear bush 21t is a much tighter fit in the gear and needed no retaining compound when pressed in with the vise. The bush was too small to slip onto the shaft at all so I reamed it to a smooth sliding fit.
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| Layshaft components, dogged 21t gear has lost its bush which just fell out. New bus is a tight fit. New bush upper, old bush lower. |
Before starting the reassembly I applied assembly grease to all the bearings
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| Assembly lube added to bearings in the RHS case |
The gear change was already assembled so I assembled the main shaft including the large shim below the dogged gear and the smaller shim above it. I added the sliding dog ensuring that it was the correct way round (recessed centre downwards)
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| Adding the mainshaft |
Latching the gear change fork into the dog, add the layshaft and pedal shaft, rotate everything to make sure it all drops down into position.
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| Gearbox assembled- this is a bit fiddly but the dog will engage with the fork and the lay shaft and pedal shaft will mesh. |
Use a suitable sealant to stick the gasket to one face of the case, and smear the other case with a film of sealant as well. I used Blue Hylomar but didn't really like it as it tended to lump up- perhaps its too old. In the end I used Wellseal brushed onto each case. I could then fit the crankshaft and assemble the centre and rhs cases.
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| Adding the gasket |
In the event I found the new bearings were too tight on the crank to allow it to be inserted by hand and my puller didnt work. I chilled the shaft in a -20 deg freezer for 90 mins and used a heated socket to contact warm the bearing. The crank then slipped in easily.
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| Centre and RHS cases assembled- Wellseal illustrated. |
Pay attention to the top end of the gaskets where they pass up to the cylinder block base. These can slip out, make sure that they are in place. Also make sure the clip of the sliding unit fits between the two lugs in the case and that the sliding member is fitted the right way round- narrow side downwards. Secure the two cases with the through bolt. Don't screw this up tight to avoid distortion of the cases.
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| Through case bolt secured but not over-tightened. |
Turning the motor over
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| Motor from the LHSnote layshaft and gear change rods in position in holes in the case, pedal driver spring clip engaged between lugs in the case |
I slipped the O ring onto the main shaft
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| New O ring on the crankshaft |
and pushed it down by hand
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| Sliding the O ring down |
It was pushed finally into place by adding the clutch centre and pushing that down; securing it with the circlip.
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| Clutch centre fitted and secured with the circlip. |
I added the clutch basket and plates
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| Clutch basket in position |
Add the 80t dogged gear and press it down and rotate to make sure its engaged. Do not forget the shim on top of this gear.
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| 80t gear fitted and shim added |
I applied assembly lube on the other crank shaft bearing and Wellseal to the edge of the case.
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| Assembly lube on LHS case, Wellseal added to flange |
Before sticking the new gasket on.
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| Gasket stuck on |
I could then assemble the clutch on the crankshaft- and Yes, I had forgotten that and had added the Wellseal too early!
This is the gear immobiliser fitted into place.Tighten the clutch nut until the clutch slips and the piston starts to move.
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| Locking device in use, tighten the clutch release mechanism until the clutch slips and the con rod moves. |
Fit the clutch cup and omega clip and grease the inside of the pedal shaft opening and the clutch turret before pressing the lhs case down. It needs to go over the pedal shaft first (use plenty of grease on the shaft and if you have the special wedge use that too). The driver unit is still secured in this case by the circlip and its a tight fit over the pedal shaft. Once the pedal shaft has entered the driver, push over the clutch turret so that the cup enters the turret. Finally as you continue to press down check that the main shaft enters its bearing- I used contact heating again on this bearing before assembling the case to ensure a smooth assembly.
Refit the 8 case screws and tighten these, tighten the through bolt from the right hand side.
Refit the 4 cylinder barrel studs (if you removed them), add the cylinder base gasket- secured with Wellseal, and slip the cylinder down over the piston. I tried using a ring compressor but actually it was easier just to use my fingers.
Add the cylinder head and secure with the 4 nuts and spring washers.
I attached the magneto backplate... This was interesting. The plate has a notch put on in the factory that should align with a notch on the crankcase when timing is approximately correct. I've always had trouble timing this motor and I've been having to use full retard, taking up all the adjustment in the slot even to get in the right ballpark. Similarly access to the points has been hard for adjustment as they don't appear in the centre of a window at max opening. Now that the magneto is disassembled, and the motor is on the bench, it's clear that these slots cannot coincide. When they are aligned the backplate screw holes are completely hidden! I tried another backplate, the earlier type with orange ignition coil and with this alignment was perfect. I am left wondering whether the backplate was changed at some point and the magneto updated to use the newer style black plastic ign coil, but the backplate used wasn't quite right for the Quickly? The old backplate I used to test fit has sadly a dead ign coil so I can't simply fit that one and I'll need to replace the coil if I'm to switch back and regain timing control. In the meantime I'll press on with this one.
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| Backplate markings aligned, mounting screw holes hidden. |
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| Close up, marks aligned, screw hole hidden |
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| Older style magneto backplate, marks aligned, screw hole nicely situated in the centre of the adjustment slot. |
The new black coil will accept a full size HT lead but this is too stiff and inflexible to route around the mag and out of the case. Especially as the Ign coil directs the cable backwards where it has to make a rapid bend against the crankcase. This makes installation of a full size cable very awkward and the rigidity makes timing adjustment very difficult. I therefore installed the thinner cable that Quicklies come with.
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| Two thicknesses of HT cable |
The cap doesn't quite close around the thinner cable so I used a small grommet first, this will fit inside the cap and make a good seal with the cable.
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| Grommet fitted below coil lead cap |
Even so the HT lead is still bent sharply on exit from the coil.
Still I completed assembly, and fitted the motor in the frame. I checked spark, added oil and fuel and hey presto she fired up! For the first time since I've had the bike it runs easily and responds to throttle!! Still needs a bit of a tune and adjustment, and I need to sort out the niggling problems with the wheels etc then it should be finished!!
The Quickly mainshaft only has one oil seal on the sprocket side (not magneto) and it's 12 x 32 x 7
Crankshaft has 2 seals - 20 x 35 x 7 and 15 x 24 x 7. With 2 x 6202 bearings
