Thursday, May 31, 2012

Rear mudguard, expansion tank and chain guard



 Unsurprisingly, there was a lot of corrosion on the rear mudguard fixings and brackets.

Drilling out remains of ally rivets that
hold a rubber gator to the mudguard
Coolant expansion tank with failed
rivets on a metal bracket that holds it to
the rear mudguard. Outer holes have captive nuts
for expansion tank bolts. 
The coolant expansion tank is bolted to a steel bracket, which is in turn riveted to the mudguard. The rivets had failed and the plate heavily rusted. The expansion tank bolts run through brass sleeves - they were corroded too and needed soaking in WD40 for weeks to release. Heat wasn't an option with a plastic tank. Got there in the end though.

A rubber gator bridges between the forward edge of the mudguard and swinging arm. It is riveted to the mudguard through a metal plate, and to the swingarm via another metal plate. All the rivets were heavily corroded, their aluminium heads basically dissolved.

Grommets and rusty spacers
Repainted spacers
 The mudguard is bolted to the frame via rubber grommets and mushroom shaped steel spacers.
 I gave everything a good scrub up and derusted the spacers prior to repainting. The metal brackets were not worth saving. I made up replacements from 3mm aluminium plate.

The bracket for the expansion tank was very simple - just a strip with four holes in it. I decided to cut M6 threads in the outer two to accept the bolts for the expansion tank and to use lock nuts for strength.

The lower bracket for the gator was a bit more involved. It has an S shape profile, with three 5mm holes for rivets uppermost and two 8mm in protruding lugs on its lower edge for bolting to the swing arm.
Two aluminium plates to replace failed steel items - top
bracket in picture is for expansion tank, bottom for lower
edge of rubber gator.
I made up an additional gator (or mud flap) to fit beneath the standard gator, to give the shock absorber and its linkages a bit of protection from the elements. I shared the M8 bolt holes in the swing arm  for the standard gator's lower bracket and my additional gator. Rubber isn't very strong so I made up an extra aluminium strip to spread the load from the bolts across the width of the extra gator. The gator was made from a cheap car mat.

I painted the ally with special metals primer and Smoothrite black, and used some A2 bolts, washers and domed nuts to hold it all together.
Lower bracket for standard gator plus additional gator
in place on swing arm, VA2 dome nuts gleaming away.

Re-riveting the lower edge of the standard gator
to the replacement aluminium lower bracket,
and preparing to do the same to its upper bracket
 When the standard gator was riveted to its new ally brackets (painted black) and the coolant tank bolted up again, it was a bit of a job to fix it to the rear frame rails. The plastic is very robust but very flexible at the same time so it needed a fair bit of jiggling to get the bolt holes lined up.
Expansion tank refixed to the mudguard, gator riveted on ...

... wiggled into place beneath rear frame rails for bolting up. 
 I used a couple of elastic cords (bungees) to hold it up temporarily whilst I fitted the bolts. It worked fine. However, after I'd finished the job, I tried to fit the wiring loom and discovered that I couldn't get the block connectors through the spaces between the frame rails and the mudguard. Consequently, I had to drop the mudguard back down again temporarily to squeeze them through. So the bungees had a second useful outing for me.
Bungees helped hold up the mudguard whilst I located the
M6 bolts and mushroom spacers.
There was one other riveted bracket on the rear mudguard - a little plate for the flasher relay. I fitted that after the mudguard was bolted up. I used copper grease on all the pop rivets to try to prevent or retard the differential metals corrosion that had caused them to fail first time around.



The chain guard is held on by three mushroom-headed bolts. I decided to replace these with stainless steel button head machine screws with oversize washers. 












Friday, May 25, 2012

Shiny happy iridium spark plugs

I needed some help to torque up the gear box sprocket nut. I requires such a lot of torque that it is hard to stop the sprocket from rotating without some way to prevent that from happening. I've been lucky in the past by putting the engine in first gear so it when the sprocket rotates it eventually is stopped by a piston on its compression stroke. That's not enough by itself but combined with the rear brake (acting on the gearbox sprocket via the drive chain), it usually does the trick. So it was time for me to put in some spark plugs.   


I carefully cleaned around the spark plug holes in the cylinder head with a long screw driver with a blob of grease on the end. Dirt sticks to grease and then can be hauled up on the end of the screw driver. I also squirted some Redex upper cylinder lubricant into the cylinders, inlet tracts and exhaust ports. This should give the engine an easier time on first start up and help to shift carbon deposits from its earlier life. 

So on to the plugs. The engine was fitted with NGK DPR8EA-9. That code means they have 12mm thread (18mm hex across the flats), an internal resistor, heat grade 8, and a ceramic nose with centre electrode that extends 9mm beyond the threaded section. My factory and Haynes manuals both specify DPR9EA-9 as standard. That is a 'harder' grade that the 8s fitted. Grade is a temperature rating. 9 should mean the ignition will function more reliably at higher temperatures. I've no idea why, truth be told, but the bike was definitely running hot so I figured I might as well fit the recommended 9 grade and sideline the 8s. 

I decided to try NGK iridium plugs. These are coded DPR9EIX9. They are expensive so an indulgence. My excuse is that the bike was suffering from a misfire and I'm trying to make life as easy as possible for the ignition system all around.  

Haynes (left) and  Factory (right) manuals side-by-side
showing DPR9EA-9 specifications



I gapped the plugs at 0.9mm and smeared some copper grease on their threads. It isn't easy getting plugs in and out of these engines because the tunnels in the head are narrow. The fours are tricky enough - the triples more so because the centre cylinder is directly under the frame tube and space severely restricted.

I have one of the original plug spanners from my Daytona 900's tool kit but it is a bit too short to use comfortably with a torque wrench. It has a 12mm internal hex and I have used a oil drain plug key and a socket to work this before. However I found a longer 18mm spark plug box spanner at an autojumble. I think it is from a Suzuki tool kit. In any case, the good thing about it is that it takes a 17mm socket on the top without protruding so far it interfers with the frame. So I could enjoy hearing the satisfying click of my torque wrench at the prescribed 18NM.



Wednesday, May 16, 2012

Saturday morning: a mini milestone

After months of painstaking work (or fanny about, if you prefer), the rear suspension, wheel and drive were finally reunited in perfect harmony. That means she can be rolled around again, albeit in minimalist stripped-down form.

Well, OK, that might be a bit of an overstatement but still it was a big moment for me to be able to wheel wonderful Wuby awound again.So, to celebrate, I did a couple of little walk-around movies.

From the left:


video

and from the right:
video


Beautiful smooth running drive chain action:


video

It's amazing how light a big bike can be .... when half of it isn't there!

Monday, May 14, 2012

Utterly horrible

I'd meant to post 'before' pictures of the drive sprocket and its housing with the 'after' pictures from my last post. Externally, things weren't too bad. Underneath the slight patina of age that adorned the sprocket cover, it was a whole different story.

 

Removing the sprocket cover revealed an utterly horrible sight: years of sticky chain lube plus road dirt and metal particles from the terribly worn sprocket, all packed tight around the chain and clutch pushrod.

I scraped all the muck out into some old newspaper, with judicious use of a large screwdrive. I swear, it must have weighed a kilo - like a generous portion of fish and chips.

The sprocket was loose on the gearbox output shaft - the lock washer was the only thing that had stopped it coming off altogether. Nasty. At least I didn't have to fight to remove it.

Although I've seen pictures of teeth in worse condition before, I'd never come across a sprocket with more wear than this myself. The teeth were no more than a third of their original width and distinctly hooked. More like barbs than teeth. Here's a repeat of an 'after' picture for easy comparison.


Sunday, May 13, 2012

Reassembling final drive

I decided to gear the bike up for a lazier ride. So I got a 19 tooth gearbox drive sprocket, one tooth larger than standard, and a 42 tooth driven sprocket. 


It is impossible to torque up the gearbox sprocket nut to the required torque of 132NM without being able to stop the sprocket from rotating. I have found the best way to do this is to put the gearbox into first gear and to hold the rear brake on. That way, the gearbox sprocket is held still by a combination of engine compression and brake pressure. So it was time to fit the rear wheel.






Mushroom type spacer on right
of wheel. The wide end butts up
against the rear brake bracket

Rear wheel spindle, spacer, rear brake
bracket, bush and wire retaining clips
The rear wheel fits onto its axle between a small alloy spacer on the left and two spacers on the right.  The right-hand spacers are a large, mushroom type spacer that fits into the rear wheel, and a large aluminium bush that fits into the centre of the brake bracket.

The rear wheel, fitted with sprocket carrier and small, left-hand spacer, has the chain looped over its sprocket pushed well forward to maximise chain slack. The eccentric chain adjusters should also be turned so they are aligned to the same marks on the swingarm and pushed slightly outwards from the centre of the bike before being nipped up with an Allen key. This makes the gap for the rear wheel as wide as possible to help you get the axle through. It's easier to see what's happening this way.

The rear wheel spindle needs to be fitted from the left because it is isn't easy to manoeuvre the wheel into place, and the sprocket carrier side is the heavier of the two. I put a wooden block under the wheel to help support the weight.
Greasing the large aluminium
bush for the centre of the rear
brake bracket

Axle right through, bolt being
wound home. The gap between
eccentric adjuster and brake
bracket is visible here. 
I used plenty of Castrol LM on the mating faces of all the spacers, the brake bracket bush, and the axle itself. With a  bit of wiggling and the assistance of a rubber mallet, the axle through each of the components in turn.

The right-hand bolt is wound in with at 12mm Allen key, pulling the swingarm legs together against the spacers. I nipped up the axle bolts at this point before slackening off the eccentrics to adjust the chain tension, and to allow them to move inwards to their correct position.

132NM of torque for the gearbox sprocket
I refitted and bled up the rear brake and then was ready to torque up the gearbox sprocket.



It worked a charm but needed a steady hand and my largest socket (36mm). That just leaves the flattening of a tab on the gearbox lock washer  - that done, job's a good un. 





Wednesday, May 9, 2012

Refitting the swinging arm, rear shock and centre stand

The swingarm had suffered from scuffing towards the left-hand end. It also had pitting from corrosion in areas where water and salt had crept under the chain guard and gator which connects to the rear mudguard. I treated those areas with special metals primer, topped off with silver Smoothrite. When the mudguard and gator are replaced, they'll be hidden anyway - it's good for me to know they'll be protected from similar problems in the future. 
The main  suspension components for the swingarm include hollow spindles for two drop links that connect to the drag link. The spindles have grease nipples in their outer ends - these appear to have been used as intended.  The spindles fit through three short sleeves in the swingarm casting. These had suffered a bit. The drop links have needle roller bearings at each end and are both protected from the elements with decent seal arrangements.  The top bearings benefit from large steel and rubber seals, the lower bearings are looked after  by pressed-in rubber seals. All were in good condition. 
Drop links - Meriden-style
logo on these early castings

Needle roller bearing was in
great condition, visible here after
cleaning out the old grease with parafin

 I reassembled the drop links with new sleeves and a combination of Castrol LM for the needle rollers and Rock Oil rubber grease for the seals. Torquing up the spindles is a bit tricky - the trick is to use a socket for a 12mm spark plug because these are 18mm across the flats.

The chain has to be looped over the left-hand leg of the swinging arm first. The swingarm slides in between the frame outriggers and steel castings. The castings should be left loose at this stage - a bit of movement is helpful to get the swingarm positioned properly. The swingarm spindle is inserted from the left because it makes it easier for dealing with the chain. Stop when the spindle gets to the first steel casting. An alloy spacer must then be inserted between the steel castings. 


Alloy spacer in place between the two steel
castings. The return springs for the centre
stand are visible, hooked on to small
protrusions on the castings. 
 The rear shock is best mounted after the alloy spacer - there is very little room for manoeuvre when the shock is in place. I supported the rear of the swingarm with bungees looped over the frame. This helped maximised the room I had for wiggling the shock into position, and then to line up the shock's lower eye with the bottoms of the drop links for inserting the drag link spindle.   I put lots of grease on the edges of the drag link that would but up against the drop links and shock. There was a fair amount of corrosion on the drag link there, especially to the left of the shock mounting point. I'd seen this on all three of the drag links I'd looked at previously so it's well worth the trouble of slapping on the LM at this stage.

Inserting the drag link spindle from the right-hand side
through the right-hand drop link, shock lower eye
and then manoeuvring the left-hand drop link into place.

The large hex bolt with grease nipple about
to be wound in to the left-hand end of the drag link spindle. 
I decided to polish up the eccentric adjusters for the rear wheel. They were scarred by heavy-handed attempts to refit the rear wheel in the past. I got most of them out with wet and dry abrasive paper on thick pane of glass. Then I polished them with drill and mops. 


 The centre stand fits to the lowest holes in the steel castings. I found it easiest to attach the return springs by looping a 12mm ring spanner over the lower ends - it meant I could get a good grip to pull them over the prongs on the stand.

All sorted, ready for the rear wheel.