450 MKIII 428 Sprocket wear opinions please.

[themoudie]

Another oil change and another strip, clean and re-lubricate the chain, as I do these at 1,000 to 1,200 mile intervals on the 450 MKIII. No track use, but varied road use on a few motorways/dual-carriageways, but mainly A, B, C and Unclassified single carriageway/track roads, in all weathers, throughout the year.

I have a 17:42 sprocket pair, with a IRIS 428 chain, rather than the the standard 3/8" x 5/8" chain.

I understand that chain wear maximum is 1/4" for every 12" of chain length, at present, after 8,000 miles of varied road use, I have 3/16" of wear for every 12" chain length and no tight links.

Attached is an image of the wear on the 17 tooth steel gearbox sprocket, the 'Talon', alloy, rear sprocket has similar wear.

Would you clean and re-fit the current components, or fit new components?

Thank you for your time and good health, BillR

[Duccout]

Hi Bill,

What does the sprocket look like on the other side?


Cheers,

Colin

[graeme]

Looks like it’s not aligned ?
But hard to tell without seeing the other side.
Regards
Graeme

[Bevel bob]

Appears borderline , ok for my 250 and very sporadic light use ., but not for a 450 used regularly over distance . Sprockets out of line a bit ?.

[themoudie]

Thank you for your time and thoughts.

The wear that you see on my first image is matched on the inside of the sprocket. Unfortunately, being a Luddite, I don't have a "Smart" phone and my wee camera is unavailable, so a flat bed scanner has had to do.

Hence the peculiar perspective and rendition of the 2 images attached of the previously unseen parts of the sprocket. I shall be out cleaning up and sorting out the final drive, before fitting the new parts, after posting this. Quality parts, worth every penny, British sprockets and German chain.

Good health to you all and keep wearing the beasties out, BillR

[Duccout]

Hi Bill,

I agree with your decision, nice new chain and sprockets will please your old bike.

Cheers,

Colin

[blethermaskite]

Hi Bill, I would just do a check on your chain alignment when you are fitting your 'new bits'......its hard to say but it does look like alignment may have been a bit off. Cheers George

[themoudie]

Thank you for the additional posts and opinions.

Having had a good squint at the sprockets, swingarm and the frame all appears to be square. This old bird was thrown up the road in spectacular style in 1978, coming to rest having hit the kerb and done multiple somersaults, bending the right hand handlebar parallel to the fork stanchion, putting the tank hard against the frame top tube and bending the right rear shock upper mount at 90° to the horizontal. Before the last rebuild I had the frame and swingarm stuck in a "Motoliner" and straightened out, 1/2" difference between the swing arm ends, in relation to the swingarm front tube. Finally, when I changed over to one of Nigel's taper bearing head race sets, it was found that the top yoke was way out of square! No wonder the handling was a bit different, nervous, when compared to the pre-accident handling. Squinty frames/swingarms do make peculiar wear patterns on sprockets, but the wear pattern on both sides of the sprockets reaches to the same depth on both sides of the sprocket when measured from the tooth tips and valley bottoms.

When tightening the adjusters, I push the wheel spindle as far forward as possible in the swing arm ( the distance from the front of the axle slot to the centre of the swingarm pivot is equal on both sides) and then tighten the adjuster nut equal numbers of flats, until the chain is correctly tensioned, then lock in place, using the lock nuts. Cam swingarm pin mounts would make the whole job easier, but ......

I will, as suggested, make further alignment checks with the new components in place.

Easterlies are a bit chill at the moment and "William Wall-Ice" the BEAR gritter came past the house tonight chucking salt about, onto a dry road! Maybe the odd light shower, but the wind has been hoovering moisture out of everything. Test runs on the untreated minor roads.

Good health to you all, BillR

[Duccout]

Hi Bill,

That wind has been chilly down here in the Soft South, so it must be a real howler up there in the Frozen North. Keep your thermals on for a while yet!

Cheers,

Colin

[themoudie]

Aye Colin,

It's no blowing that hard, but coming in off the North Sea that is as cold as charity at this time of year. Being in Essex it'll be dry as the Gobi and chilly, same as up here round Perth that has it's own micro climate. we have annual rainfall around 28", whilst 2 miles west in the village its 32" and a further 16 miles west in Creiff it's up around the low 40's".

Must off out, as the sky is blue and fresh and there's some spanner twirling to do. Maybe a canter this afternoon.

Good health, BillR