Author Topic: raising the c5 gearing  (Read 2358 times)

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shappers

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on: July 17, 2010, 04:07:43 pm
Hi y'all, got the cb400 wheel fitted and went for a test ride.  What with the larger tyre and 35 tooth sprocket the gearing was too high.  50mph in second, 65mph in third at around 4750 rpm and never got near 80mph in fourth.

At more moderate speeds the lack of cushioning made for very noticeable vibration throughout the whole bike, and town riding wasn't as pleasant.  I've already put it back to standard.

When cleaning up the brake drum I found it had stated to crack so wasn't going to chance a longer term test nor spend money on a range of sprockets or tyres to find an optimum.  .

Should anyone else have a go then go for a wheel with plenty of drive cushioning like the Enfield and check it before doing too much work.

Looks like its back to plan B with welding a 19 tooth sprocket onto an 18 tooth centre.

Cheers, Shappers.


Drifter

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Reply #1 on: July 18, 2010, 01:06:16 pm
To bad the honda wheel did not work out...what was involved in getting it to fit and the chain aligning correctly? Even though the gearing was tall did you get a feel for how the bike works with taller gearing?  Just putting around did it have enough torque? This kind of stuff is fun, i always enjoy a bike experement.

Slapper, thats a good idea as well.


shappers

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Reply #2 on: July 18, 2010, 07:34:38 pm
Hi Drifter the L is no where near the H.  Aligning the sprocket and chain involved spacing the wheel from the swinging arm which I did with a handful of washers on both sides which left the centre of the rim about 2mm off the bikes centre but I couldn't feel any difference there.  I went for a cable brake operation and can say its not worth the effort.  Making up a cross shaft and linkage would be better.

The larger tyre was equivalent to having a 32 tooth sprocket.  Gearing this high made town riding fall between 2nd and 3rd at 30mph and 3rd and 4th at 40mph which made it a bit revvy or a bit snatchy.  I think with the 18/35 tooth or 19/38 tooth or the 428 24/48 tooth combination it would be fine at town speeds and would just cut the revs enough at speed to be worthwhile.


Drifter

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Reply #3 on: July 18, 2010, 09:25:40 pm
Shapper....got it right this time, sory bout that l and h thing.
So did you like the taller gearing at all?  2mm is not much, the 800 Kawasaki Drifters have a 1/4 in difference between the 2 wheels.

Any time the rear tire is alot wider than the front it makes cornering different and more work to push it over.  My cruiser is alot of work in the curves, the Triumph just glides around.


shappers

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Reply #4 on: July 19, 2010, 06:33:40 pm
Hi Drifter, thanks.  I sure the C5 will benefit from a 19t gearbox sprocket.  The gearing is more critical than I thought, and what I had was too high.

I had a chat with a well known enfield parts supplier in the UK to run my idea of 24t and 48t sprockets using 428 size chain.  There is no need as they are already in the process of sourcing tooling to produce a 19t sprocket.  Probably by the time the new catalog is released in October or November.

Therefore I'll stop all development await developments.  As it happens my C5 has started the decompressor clack but only occasionally.  As the right hand cover has to come off to change the sprocket I may remove the decompressor if its still playing up.

Cheers, Shappers.



Drifter

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Reply #5 on: July 20, 2010, 03:13:13 pm
Cool, good to hear its in the works, the broach to make the sprocket is around 8000 thousand American dollars so they must expect to sell alot of them. Local machine shop wants to much to mate 2 sprockets together so im with you...in due time a 19 will come around.