Week 22: 21st May

What a week – the Atlas limped into life on Monday morning but needed a bump to get home. Sick and tired of this so slung it in the back of the garage and spent the rest of the week on the VFR!

The roadworthiness test is looming so it was back into the garage on Friday to start going over the bike. Front tyre needs to be fitted, horn worked (surprise), indicators AWOL (no surprise) – speedo still out of order but then that isn’t an MOT check so no worries..and finally I had to admit the headstock bearings were knocking and the knock couldn’t be adjusted out – that means dropping the forks which I wasn’t lookig forward to.

It was roasting hot all weekend so I took the work in stages. First off I put the Atlas on a box (no centre stand), removed the front wheel (checked the front pads which are worn but within limits) and then set about the forks.

At first I thought I might be able to get away without removing the handlebar fairing but in the end decided it was easier with it off. It wasn’t so bad once I had the top yoke off and the ridged bearing races revealed…

Re-assembly worked out fine and provided the opportunity to look at the various cable and wiring runs which needed tidying up from the last time (yes did this when I first got the bike but because I let the bearings go slack here I am just two years on repeating the process again). I also adjusted the throttle cable which I’d made too tight and had been raising the revs on full lock. I decided that as I’d have to re-tighten the bearings later on I’d leave the fairing off for 500 miles.

Forks assembled it just left the front tyre. I went for this at 8.00 on Sunday morning to avoid the heat and compared to the rear tyre it was a doddle…however in future I will only buy tyres from a shop that’ll fit for free.

So all assembled bar putting the tank back on and I wondered if I was suffering from poor earth’s on the starting side – I’d seen a post about starting an RGS on the Laverdaforum and Keith Nairn’s advice had stuck. Well cleaned the earth point and tightened the battery terminals and bingo!

Let’s see if it holds out next week…

Nick 🙂

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Week 21: 14th May

Back to the wretched Atlas sprag which worked once on Monday morning but required a bump start to get home…

By happy coincidence I was able to pick up a complete Zane replacement on Wednesday. I was initially disappointed to find that it was not a simple case of off with the old and on with the new.

The sprag’s are broadly the same but operate on two very different systems. The Atlas is derived from the 120 triple roller/plunger/spring setup whereas the Zane has the modern one way sprag bearing arrangement.

When I came to fit I found that the ring gear pushed too far back on the crankshaft leaving the top edge of the crankshaft splines on display – the consequence of this is that the ring gear just ‘kisses’ the engine balance gear and also makes it not possible to lock up the sprag against the back of the rotor. To solve this I had a spacer washer made up with some additional shims. I was pleased with my solution which not only shimmed the ring gear correctly but the stepped washer also prevents lateral movement in the needle roller that sits in the sprag.

I thought I had a Zane alternator case but it turns out not so. (it’s my gearbox cover) This then caused my next problem which is that the Zane idle gear is countersunk by 14 mm whereas the Atlas original just 9 mm. To get the Zane part to fit I therefore need to either get the gear or the casing altered. Over next week I am going to try and get the gear altered but apparently cutting through the case hardening will be the main obstical.

On a compare and contrast the gear ratio’s are different::

Atlas idle gear 48/21 teeth whereas the Zane runs 50/19
Starter gear on the Atlas is 84 teeth and the Zane 86

I got round the problem of not being able to fit the Zane idler gear but putting in the Atlas original. I took advice from the micapeak list and Hande responded confirming my worse fears: ‘In your mixed system you are running a gearing ratio of 10/48=4.0 and 86/21=4.1, which works out to a total ratio of 4.0 x 4.1=16.4. This is the tallest ratio you can get with the parts – and the worst in my opinion. This loads the starter motor and battery the most. In percentages compared to the Zane setup it is 27.6% higher/taller gearing, and compared to the Atlas setup 14.6% higher. So it spins the crank about a third faster than the Zane setup or a sixth faster than the Atlas setup – if your battery can take it! And I think it can’t.’

Anyways the good news is that the Atlas now starts pretty well on account that the new sprag grips the crank far better.

Other things on the horizon are the roadworthiness test for the Atlas on the 31st May. I have to get the indicators, horn fixed. Possibly fit a new front tyre and disc pads + check out the headstock bearings which I think are loose…If I can get this done and finally bring the sprag up to Zane standards then maybe I will have the time to get a proper run at the other bikes in the garage!

Nick 🙂

Week 20: 7th May

Well the trip to Scotland came to an end on Monday at 20.00 when we pulled into home.

On Tuesday I got the broken pillion footrest welded for a tenner. Job done and not sure if I’ll try and get a replacement or whether I will just ride about with the battle scar to remind me of a fabulous trip to Scotland. All those scrapes and dents tell a story hey?

I was in two minds about taking the Atlas to work on Wednesday but thought ‘what the hell’ but had my doubts as it limped in to life…Sure enough that evening the starter sprag packed in and I had to face the humiliation of being bump started by my work colleagues. Once running it was fine and I even rode over to Basingstoke to pick up some Jota handlebars for a friend in Texas – just left it ticking over as I chatted to the seller and looked at his collection of bikes (as you do).

Two VFR days followed….

Made some progress on the RGS. I had a tool made up to put the piston seal into the master cylinder. I was in no hurry so decided to get a hollow punch made up (50mmx20mm length of bar with a 16mm bore sunk to 30mm) – cost me just £5 from the local machine shop and saved a load of hassle!

Just in from the garage after I’d changed the Atlas oil and fixed the sprag once again. This time the strip down revealed damaged springs and one plunger shattered. Despite renewing the springs and the damaged plunger the bike limped in to life…I have an email out about a Zane sprag clutch that I believe Bob Dixon has used – I doubt the Atlas will last the week…

Nick 😦

Week 19: 30th April

Well this week was all about taking the Atlas up to Scotland for a long weekend – see ‘Trips’  page for details.

I took the Honda into the office on Thursday morning so I could have the Atlas all loaded and ready to go – so one VFR day despite using the Atlas in the evening to ride 230 miles to Scotch Corner!

Nick 🙂