
A well earned pamper
First weekend in a month where I haven’t been off travelling at the weekend so a chance to give the Atlas some TLC.
On Monday I had to fit a new brass nut to the offside exhaust to stop it blowing. It’s done the job and brightened my mood as I was beginning to get a bit ‘pissed’ at tinkering. Funny how just a little thing like this can drill into your mindset. Once done the Atlas performed it’s daily commuting duties with ease.
Anyways back to the main service I changed the oil and seeing as the engine was empty used the opportunity to fit the ‘tight’ sprocket to see if I have found a solution to the rattling gearbox sprocket that then leads to wear on the ouput shaft. I hadn’t been looking forward to this because I feared that getting the old oil seal out and the new tight sprocket on would end up being a battle of will’s.
It turned out however to be quite straightforward – the original oil seal popped out with a bit of persuading with a screwdriver and was installed using the old loose sprocket as the flat surface to act as the intermediary with the long socket and big hammer!.

Original seal to left, thinner replacement to accommodate sprocket ‘boss’ on the right.
I see that the seal I’d been given by the engineer who knocked up the sprocket is double lipped. My only concern is that when the sprocket boss entered the seal it didn’t damage the edge – there is a leading edge on the sprocket boss but it is quite small. I will only be able to tell next weekend when I should have knocked up 400 miles on the conversion.

Sprocket in situ. just the locking washer to add
To get the sprocket on I heated the sprocket to 180 degrees in the family oven and then used a deep socket to hammer it into place. The sprocket doesn’t chatter now!

Output shaft – note wear on splines at 70,000 kms. Shaft shown with oil seal
The old sprocket that I removed was still in good condition. What I found interesting was the condition of the lock washer which shows signs off rocking – the locking tabs are significantly flattened/worn.

wear on the locking washer
Now with the tight sprocket and integral boss the locking washer is a ‘belt and braces’ addition – I am considering getting rid of it altogether and using a circlip once I have proved the concept.
So sprocket in place I replaced the chain with a lighter non- O ring item. The O ring job was cleaned and ready for my next two up adventure. I’d used special chain oil on this O ring chain and it was a sticky mess which I cleaned off with engine oil before storing in a sealed bag. I remain surprised at the significant weight difference between the two types of chain and also the relative flexibility. Running an O ring chain has to stress the gearbox and rear wheel wheel bearings more?
Last task was to go back to the front brake and inspect the calipher and disc. Ever since I fitted the 320mm Yamaha item it has felt warped. The calipher was slightly off centre meaning one set of pistons was slightly more pronounced – however this doesn’t account for the warped feeling.To make it more central I installed the original washers (that sit between the calipher and the fork leg) between the calipher and the spacing plate.
I pulsed the brake lever and all four pistons were free so a jammed piston was eliminated.
As a precaution I ended up fitting another 320mm disc (I bought a pair) so let’s see what the week brings.
Nick 🙂