Superfour sprocket changing questions

[jack]

Hi all,

This is my first post to the forum, having become the proud owner of a Superfour this summer. I was pleasantly surprised to find a dedicated forum for the bike, and have already gathered much helpful information from the forum archive. So thanks all!

I've just bought a Scottoiler for the bike, and in the process of sussing out the fitting noticed that the rear sprocket seems to have a guard riveted to it that makes fitting the oiling tube a wee bit tricky. Since I seem to spend a lot of time on the motorway anyway, I figured this might be a good opportunity to get a new sprocket and change the gearing a bit.

I was thinking about dropping 2-3 teeth, but wondered a few things.
- Is there a reason that I might wish to gain a tooth in the front sprocket, rather than dropping 3 in the rear as I was planning?
- All the advice I've ever heard is to replace both sprockets and chain together to prevent the new part being excessively worn by the old components. The chain I currently have is a DID job, and looks to be in good nick. Would it be a false economy to leave the chain as is and only buy the sprocket I need?
- On a similar chain related note -- if I drop a few teeth in the rear sprocket, is it acceptable to take up the extra chain slack by adjusting the wheel backwards a bit, or is it necessary to get a new chain / lose some links in the existing one.

Apologies for the newbie-esque questions. The internet seems full of conflicting advice, and I would very much value the opinion of any CB400-er (or anyone, actually!) willing to share their thoughts.

Cheers,

Jack

[Superjack44]

Replacing both sprockets and chain at the same time is good advice, pattern sprockets usually dont have that guard on so aligning the scott oiler tube is a bit easier.
Getting the right amount of oil through can be a bit time consuming but worth it, when I fitted mine I fitted a T piece into the vacumm pipe that opens the petrol tap and fitted the pipe along the left hand side of the frame to the scotoiler reservoir, I started the bike and set the unit to prime ,this is the fastest setting to encourage oil flow through to the nib (I usually encourage flow by fitting a small bore plastic pipe over the nib and sucking on it and wait for the oil to be seen emerging from the clear tube down towards the nib saves a bit of time) once it emerges from the nib time how long it takes for a drop to emerge (I aim for 1 drop every 2 minutes) If too much oil comes out the reservoir will drain quite quickly and you will find cornering interesting as oil gets onto the rear tyre.
When I changed mine I fitted a 16t front and 38/39t rear performance is altered a bit (I was looking for better mileage) on tour with panniers and tent I was getting in excess of 70mpg without luggage I got up to 87mpg but that was just pootling around about 60ish acceleration in 5th and 6th was nothing to write home about 1st, 2nd, 3rd and 4th was acceptable but I am getting on a bit and it does me.
I adjusted the chain tension without having to cut the chain.
If its out right acceleration you are looking for front sprockets are available in 13t (I think) 14t , 15t, and 16t
rear sprocket is I think standard 42t .
Hunters of Newcastle do chain and sprocket kits.
Enjoy the bike they are little corkers.

[jack]

Howdy --
Thanks for your reply, I'm in something of a "learn by doing" phase, so it's good to know that I'm not about to do anything *too* ridiculous. I've decided to go for the 16t front, and stock 42 rear -- Maybe grab one of those 13T fronts you mention for the weekend(!) -- I think I'll probably replace the chain, but stick with stock length. Will be good to get back on the road.

Thanks again,

Jack