Shock absorber replacement and rubber bush swap

The shock absorbers on my bike were leaking when I got the bike and had developed an obvious squeak when under load. The original shocks are non adjustable and obviously designed with Japanese riders in mind. A sensible upgrade (considering my size and weight) would be to replace with adjustable shocks and set them for a smoother ride. I bought a pair of Biketek shocks (SHKC90) from Motorcycleparts. Co. UK. These are black shrouded shocks because exposed spring shocksdon't look "right"  on this bike. The C90 needs 335mm shocks equipped with eye mountings top and bottom. In fact for my bike the top eye mounting should be 12mm and the lower eye 10mm. This is a bit odd since both securing cap nuts are M10 but is explained because the upper mounting has a shoulder behind the thread. Despite the advertised shocks being suitable for all C90s, they actually had 10mm bushes in both eyes and so will not fit unless modified. Interestingly the suppliers acknowledged that this problem had occurred before, although surprisingly it hadn't caused them to modify their applicability statement!!! They were not able to supply them with the correct bushes. I decided that I did want to fit these shocks and therefore need to change the upper bushes. These are available as sets of 4 rubber bushes from around £5.

Shock absorber top eye as supplied with 12mm steel sleeved Bush. 

It's simple to press out the top Bush using 2 sockets and a vice. Here I'm using a 21mm 3/8 drive as receiver and 12mm 1/4 drive as press. This latter is about the same size as the inserted sleeve but has to be used because unlike the original Honda shocks, the eye on these internally. It's 21mm at the opening but narrows to 17mm in the centre. It is essential that the socket used can fit through the narrowest point or it will crack the eye as pressed. 

The smaller socket presses the sleeve though and once its about halfway out it can be removed and the rubber bush pressed out by hand. 

The empty eye showing the internal narrowing. This shape is mirrored in the shape of the bush. 

Rubber bush removed

Fitting the new bush is slightly more complicated because if you attempt to press it into the eye using the vice, the end of the bush will just flare out and jam. To prevent this and make sure that the bush enters squarely, fit a jubilee clip around the front of the bush and tighten it to make a small compressor. Flood the area with silicone lube and then press in using the vice. The clip holds the rubber  compressed so that it can enter the eye evenly. Once its started remove the clip and press the rest of the way in and tap it fully home with a socket.

Coil, CDI unit and flasher relay

I'm hoping that swapping the cdi unit and coil might cure my running problems. At least one report on the owners forum implicated the coil in problems like mine where the motor simply refuses to give above half throttle. Trouble is for both of these items you can't test them, you have to substitute and see if anything is better. The flasher is a separate issue... Seems that my indicators flash very fast, and in this model of bike the relay is located with the first two items inside the frame. This means that its conveniently replaced at the same time.

Start by removing both side covers.

Disconnect the battery and then remove the clamp screw that holds the retaining bracket and remove the battery

Unscrewing the bty retaining clamp. 

This exposes the battery tray

... which is removed by taking out the 2 10mm machine screws

The battery holder then comes off

Revealing the internal component holder that fixes the flasher relay and the CDI unit inside the frame. This is held by a screw at top and bottom on the rhs  and a stud that passes through the body and is secured with a larger flange nut on the lhs.

Internal components bracket, left and external bracket holding reg/rectifier and starter relay. The larger black box at extreme lhs is the cdi unit and the smaller box to the right and just above it is the flasher relay.

Central flange nut on lhs securing internal holder.

However, before this can be removed its necessary to remove the exterior bracket that holds the finned regulator/rectifier and starter relay, these share a top screw. This is held by a single 10mm screw. This bracket will then fold down. 

You can then remove the top and bottom bolts from the internal bracket on the rhs and the nut from the stud on the lhs  that secure the internal component bracket and lever this out of the frame.

Removing the rectifier bracket common screw

Both brackets will then hang on their wires.

The internal component bracket carries two boxes, each held on by a rubber clamp strip.. The larger of these is the cdi unit, the smaller is the flasher relay.

Both pull off their mounts and can be easily swapped for the replacement units. The flasher unit just pulls off but the CDI has a retaining clip that has to be depressed before the multiplug will come apart.

connections to both relays

Its hard to see the coil but this is attached to the inside of the frame at the top. Its just visible below at the top of the cavity with its two LT wire supply

Internal components removed, coil just visible inside the frame top right (green and white wires)

The coil is held on its own little bracket which is in turn secured to the bike by the upper of the two 10mm flange nuts seen below.

Removing this nut and the coil can be finagled out. Its necessary to disconnect the HT cap and feed the HT lead back into the frame to allow the coil to come backwards and out of the cut out... coil coming out...

... and here pulled through and out of the body. The spark plug cap unscrews from the end of the HT lead so that it can eventually be pulled right back through. Make a note of the route though as you have to feed the new one through the same route.

Coil now out, I found some cracking in the insulation around the HT lead entry point.

Cracked cover to coil/lead junction

Coil held in its bracket removed from frame

I replaced the coil using a Chinese copy at £7.95. It fitted perfectly and here its been replaced in the bracket and the bracket replaced in the frame.

Replacement coil fitted

Reinserting the internal component holder.

Refitting was pretty straightforward, I found no problems although re-routing the HT lead was a bit fiddly.

Road test showed... WOW a great improvement! I cant tell which of these components was at fault but owing to the cracking on the cover I suspect the coil- or maybe just the HT lead itself. Unfortunately the HT lead isn't replaceable and the price of fitting a joiner, new lead and cap is about the same as a complete replacement coil which obviously gives a neater job so I went for that. I was able to get a genuine Honda Old stock cdi unit for £10 so overall a very cheap repair and I'm impressed with the reult. Asd a bonus my indicators also work better now, flashing slower and more quietly.

Checking and lubrication of starter chain; making a new starter cover gasket.

This is a very simple post but I list it for completeness and because often the obvious stuff is hardest to find! I have been concerned about the general noise from the electric starter mechanism, I didn't know if its clutch is slipping or if the chain is worn. There is also no provision for lubricating the starter chain and I doubt this has been done since the bike was new.

Stripping is very straightforward, you need to remove the leg shields and the gear-change lever. This means removing the single retaining bolt on its underside completely. The split in the lever can be enlarged by wedging with a screwdriver before the change lever is pulled off its splines.

Next remove the  rear lhs sprocket cover, simply two bolts at top and bottom, I found the bottom one was slightly longer although I note the parts manual says they are the same at M6 28mm.

Rear lhs sprocket cover, retaining bolts top and bottom

This reveals the neutral switch connection (green/red wire) which is a bit odd; there is no terminal on the wire, it simply pushes through a hole in the brass post of the switch and is held by spring pressure. 

It simply pulls out

Electrical connections to to the alternator need to be disconnected; these comprise one multi-block connector and one bullet connector (black lead) and are hidden beneath the rubber protective boot under the frame.

The second (rearmost) wire loom clamp has to be removed.

The second wire loom clamp needs to be removed to put enough movement into the leads.

The alternator leads are pulled out of the boot and disconnected at the multiblock (centre) and black wire bullet seen here hanging free on the left

The starter cover is held on by 4 bolts, at the top, bottom and both sides. 

The retaining bolts are of uneven length- here they are in plan, the longest bolt goes to the bottom

The cover then pulls off although it is retained by magnetic attraction of the coils on the inside of the cover and the magnets on the rotor. The top and bottom bolts are fitted through orientation bushes to keep the cover in the correct place. This is important because the coils which must fit into the rotor must be positioned correctly.

The cover then pulls free.

There is a gasket beneath the cover but provided the oil seals are functional its main purpose is to keep environmental dirt out rather than keeping oil in. In my case it was fragmented when I removed the cover.
This exposes the starter mechanism, the chain loops behind the alternator rotor and over the drive pulley at the top.

Starter mechanism, chain behinds rotor, remains of gasket visible.

Starter mechanism- note positioning bush in upper screw hole.

I ordered a complete gasket set (Hi Level 995263) as this was only twice the cost of a separate starter cover gasket. To my surprise this kit doesn't include a starter cover gasket which is surprising since the kit is specified for electric start models! I'm not going to buy a gasket separately so I will make one out of nitrile sheet- this should be reusable. The upper positioning bush remained in the crankcase, but the lower came off with the cover and has to be removed before I can draw around it to make a gasket.  These bushes cannot simply be grabbed as they will crush, its necessary  to insert a 6.5mm drill to fill the centre and prevent crushing

... before wrapping a short strip of nitrile around the bush

... and withdrawing it together with the drill bit using a pair of pliers.

I also removed the cable clamp nut and guide plate (8mm)

Cable clamp- bottom and 8mm retaining bolt (bottom).

The cover would now lie flat and I placed it on a sheet of nitrile to draw around.

The case lies flat once the cable guide and position bush are removed.

I laid the shaped nitrile on the back of the case and used a drill bit held in my hand to drill through the nitrile above any one hole. Doing it this way let me locate the holes by feel. I could then tap it out neatly using a 6mm hole punch before I and threaded a bolt though the gasket and case to hold it in position whilst the next hole was felt and marked with the drill bit, punched out and a second screw inserted. Inserting a screw into each new hole helps to hold the gasket in position so that it should fit when finished. Once all holes had been punched I removed the centre of the cutout and used an 8mm hole punch to enlarge the top and bottom holes to accept the positioning bushes. Make sure that the gasket doesn't foul anything either inside the cover...

...or inside the crankcase.


Gasket as finally produced.

I cleaned both gasket faces- note there was a small groove in the case (seen below) which I found blocked with grease. I assume that this is a drain hole and is needed so I carefully made sure it was clear.

Drain hole found in the cover- here its actually positioned at the top of the picture.

Having stripped the cover, I applied chain lube grease (aerosol) to the starter chain and checked that the clutch disengaged when the motor was turned with the kick-start.
Reassembly is simply the reverse of the stripping and was straightforward once the new gasket was available. I checked that the neutral light was once more functional, that the motor started and battery charge was obtained when running  before refitting the gear-change and legshields.

C90 exhaust heat shield: remove, repair mountings and replace.

The exhaust heat shield on this bike was in very poor condition, rusted through around both mounting points and vibrating badly. A new heat shield is quite reasonable in cost but by the time they've added postage and VAT, a simple £10 item has become £30! This is ridiculous when a new pattern exhaust complete with a heatshield is only £38 inclusive!! My bike has an original Honda exhaust and apart from the heat shield is in good condition. I would therefore like to keep it and remove and repair the existing shield or replace it with a used part. If I have to get a new one then I think a cheaper replacement exhaust would be better value.

First step- remove the old heat shield.
At first sight this looks like a nut- it's a badly rusted cross head screw. I think its more than likely that they will need to be drilled out.

Heatshield mounting screws, hexagonal shaped moulded to underlying structures screw head lacks any discernable screwdriver or key structure.

I didn't need to remove the screws in order to detach the heatshield... it was so corroded it just pulled off!



I will see if I can find a second hand heatshield in due course and in preparation for this I needed to remove the screws... I tried cutting a slit across the screw heads for a screwdriver, and also using a left hand screw extracting bit. No joy so I had to drill off the screw heads to release the remnants of the heatshield. This also meant taking off the exhaust because there's no drill access with it fitted. Its a simple 17mm nut on the swinging arm and 2 10mm nuts on the manifold bracket.

!7mm nut on sw arm

2 10mm nuts on exhaust manifold studs.

Exhaust removed

I drilled the heads off but this left the bodies of the screws in situ.

My attempts to remove it  by drilling them out wandered off centre... Maybe I have a problem with pillar drill so put that on the list! Anyway, I will now need to repair or replace the mounting lugs, drill and retap them to accept the original screws and fit the new heatshield. I repaired the mounting points with weld and ground them back down to match their original shape. This filled in the off-centre holes.

These new pads were then centre punched and drilled to 4mm

...and tapped to M5 using a plug tap to get to the bottom of the hole.

However I couldn't find a used heatshield for this bike and so in the interim I ordered a universal bend-to-fit style from ebay. I don't understand how 2 of these can be supplied from Japan as a pair, with fixing clips, for £11 with free postage when a single item from CMSNL costs more and has postage of £15 applied on top! 

Anyway, illustrated is a single heatshield, its fitted by Jubilee clips threaded through the slits in the structure so it's held slightly above the pipe. Unfortunately the clips need to be undone completely to feed them through the slits and the style supplied don't open right out. Although these would be fine for a simple over the top mounting, I think that will look bad so I used conventional 1" Jubilee clips. 

The shield is folded to match the bends in the pipe and secured with the clips.

This fastening doesn't require the original screws or my laboriously repaired screw thread bosses, but at least these are present if I ever get a replacement Honda shield.

I refitted the exhaust and ran the motor. I found that the screw holes actually penetrated into the exhaust (I don't know if this is a consequence of my drilling) and needed to be sealed. I inserted M5 crosshead screws using Loctite 272 (heat and oil resistant) to make sure that the screws didn't leak exhaust gas or come out again. 

Indicators

Other jobs done while I was at it... Swapped both front indicators for new pattern replacements. They were both cracked and loose. I noted that their wiring was different. My bike had a single wire from the flasher to the headlamp nacelle and a separate earth from the nacelle to the flasher mounting screw. This is shown as such in the C90T parts list, but not in the Haynes manual which shows two wires emerging from the indicator to enter the nacelle and connecting via bullets... black connecting to a live feed and green to an earth. I think this must mean that the indicators used on the C90T and later earthed the bulb internally to the indicator body. My replacements have two wires and so possibly do not work in this way so I connected them as the older style shown in Haynes. I may have to add a separate "good" earth inside the headlamp later if this is a problem. Colours were different though so I kept black for live and used the bl/wh stripe as earth, connecting to green.

Headlamp rim was rusty so I removed it, treated the rust with Jenolite and sprayed it satin black. Please with the effect.