FOAK question - sprocket bodge ideas

If one wanted to significantly gear down, and the font sprocket was
already the smallest obtainable, and no larger rear ones were listed,
one would simply have a one-off large alloy rear sprocket made up.

If, however, the original sprocket was a steel item with built in
'bosses' which transmit the drive, how might this be achieved?

(Very small) illustration from parts list shows what I mean.

http://www.ps-fisher.demon.co.uk/pickchurs/sprocket.jpg

The ideal solution would result in the ability to bolt on standardish
alloy sprockets.

Would this be even remotely feasible.?


--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera GFR Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

It's feasible if someone makes a quick-change system for whatever bike
it is, like the one I've got on the MV[1]. If not, you could get a
carrier made to take the quick-change sprockets currently available,
but I doubt it'd be cheap.

[1] http://www.ferracci.com/store/cart.php?m=product_detail&p=345

--
Krusty
www.MuddyStuff.co.uk
Off-Road Classifieds

'02 MV Senna '03 Tigtona 955i '96 Tiger '79 Fantic Hiro 250

 

Doesn't necessarily need to be quick-change so long as I end up with a
larger sprocket (subject to the constraint of clearance on the single
sided swinging arm). I could gear back up at the gearbox sprocket if
required. Rear sprocket changes requiring the wheel out (and the cush
drive assembly) would be a pain, but not too bad. The main problem is
the use of bosses integral to the sprocket to transmit the drive. If it
wasn't for those I reckon Supersprox or Talon could knock me something
up easily.

A hill climber suggested trying Talon as they are close to him. I am
hoping they could use an old sprocket as the basis of a carrier and
machine it to take conventional alloy sprockets somehow.

I will take him up on the offer to take an old sprocket in to them to
see if anything is possible.
--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera GFR Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

My point was that QC carriers are made for many bikes (one of which may
fit yours), & using one removes any OEM sprocket issues so you can use
any size. The QC aspect itself is pretty irrelevant.

Talon make their own QC carrier so might be able to modify one to fit
your bike. You could then use their standard sprockets in pretty much
any size & colour you fancy.


--
Krusty
www.MuddyStuff.co.uk
Off-Road Classifieds

'02 MV Senna '03 Tigtona 955i '96 Tiger '79 Fantic Hiro 250

 

They don't even make standard sprockets for this bike. If the cush drive
picked up on holes in the sprocket there would be very little problem.

I once had an ancient 'scrambler' that had a truly huge rear sprocket.
This had been achieved by a previous owner having had the outer
circumference of a large steel sprocket (presumably with the centre cut
out accurately somehow) welded on to an old standard steel sprocket. You
could still very much see the join. Amazingly it had been done with
sufficient accuracy that it worked.


--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera GFR Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

Err... I gathered that. They do however make standard sprockets for
their (as in Talon's) carrier. The carriers are different for each
bike, but the sprockets are the same. So if they can make a carrier fit
your bike, you'll have an endless choice of sprockets to fit that
carrier, iyswim.

The MV's exactly the same - a funny sprocket with raised bits the
rubbers sit in. I fitted a QC carrier mainly so I don't have to
remortgage the house everytime I need a new sprocket. I could probably
buy 20 from FBF for the price of 1 from MV, & have a far larger range
of sizes to choose from too.


--
Krusty
www.MuddyStuff.co.uk
Off-Road Classifieds

'02 MV Senna '03 Tiger 955i '96 Tiger '79 Fantic Hiro 250

 

Indeed. Unlikely they have a carrier for something just like this
sprocket mounting though (clue in subtle change to sig). Worth a try
when I can get someone to actually take one in for them to have a look
at though.
--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera (GFR * 2) Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

I've posted sprockets to them before to match up.

--
Krusty
www.MuddyStuff.co.uk
Off-Road Classifieds

'02 MV Senna '03 Tiger 955i '96 Tiger '79 Fantic Hiro 250

 

I used to do that regularly with Supersprox in the Maughling days.
Think I'll take the hillclimb UR route for this one though. No rush and
the guy who would take it in to Talon is a pretty good mechanic and can
talk them through the options.

--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera GFR * 2 Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

A mere bagatelle for somebody with a whirling machine that cuts metal.
After he's made a bagatelle, perhaps somebody could make one up.
--
Dave
GS850x2 XS650 SE6a

Teach a man to fish and he and his pikey mates will have the
river cleaned out in a day.