CG 125 Sprockets

[treeno]

Hey all! I need a new chain for my CG 125 as it is showing some wear in terms of tight in some places loose in others. So I thought I might as well replace the sprockets as well, they are probably worn too right?

Anyway, my mate is insisting I should go for a different number of teeth on the sprockets (can't remember which, maybe you can tell me). Reason being that it won't really do more than 60mph, maybe 65mph in no wind, on the flat. It gets there almost at the top of 4th, in the very low end of 5th. He is saying 5th is not being utilised so why not fit a sprocket that will give me the same top speed but using all the gears, that way it should give me more acceleration on the way to top speed.

Is this logic right? Is there any point? Will it harm the engine? Also, what configuration of sprockets would I need to achieve this?

I know you will probably say "Why bother, just wait to get a new bike." but if I am changing them anyway then it could be fun. Thanks!

[Walloper]

[P.]

You want standard sprockets on there. a CG has an engine that works great with standard gearing, altering these will not make it faster. 60/65 is what you will get out of a sub 10HP 125.

[treeno]

[Rogerborg]

As a counterpoint, I lengthened the gearing on my CG-copy engined bike-in-a-box by a full 14% (15 - > 17 teeth on the front). While it added the sum total of sod all to the speed, it made the bike feel much more relaxed and unstressed - it's a popular mod on those particular machines.

This is not a recommendation, since the CG gearing (when you factor in the rear wheel size) will be different, but at £5 per front sprocket, you could have some cheap fun trying out different ratios and seeing what suits you best.

Another £10 buys you 1-up and 1-down, and then you can speak from experience, if somewhat adenoidally.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Scootaloo]

This was my stupid suggestion...

3 up on rear, should see you using 5th gear!

Well, this is my understanding...

Whilst now, 5th gear is a bit pointless as you have to change down to keep above 60 mph, surely shortening the gears will allow you to pull slightly more in 5th allowing you to gain a few mph more top speed + increase acceleration at the same time.

Is my logic flawed?

Must say thought, the CG is hella fun to drive.
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(CBF125 - 09) (CBF125 - 11) (CB-1 - 89) (CBF500 - 06) (Push Bike) (CB-1 - 90) (XL125 - 01) (VF500 - 83) (GPZ500 - 94) (GPZ500 - 95) (GPZ500 - 87) (XV535 - 94) (XV535 - 94) (GPZ500 - 87)

[P.]

3 up on rear would increase revs when cruising.

[Scootaloo]

[P.]

There is no power in the high revs of 5th gear on a CG.

[Scootaloo]

Why? How do you know?


Maybe then Rogers suggestion of increasing the gearing to make for a better drive and get more use of 4th is the way to go.
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(CBF125 - 09) (CBF125 - 11) (CB-1 - 89) (CBF500 - 06) (Push Bike) (CB-1 - 90) (XL125 - 01) (VF500 - 83) (GPZ500 - 94) (GPZ500 - 95) (GPZ500 - 87) (XV535 - 94) (XV535 - 94) (GPZ500 - 87)

[P.]

[Alpha-9]

My mate put on wrong sprockets on his CG and now it's retarded, it can do 60+ in 4th but going into 5th just loses speed

His brakes are shit too and he's lost his engine braking on top of that

Haynes doesn't say number of teeth on rear and front by default, is dumb. Anyone know?
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Fzr-600 1999

[Walloper]

The CG I ride doesn't suffer from lack of power in top. It does feel the wind and it knows when you stick your head up into the breeze. But it holds 60 no problem.
The issue is not the gearing or engine power per say. It's just that the engine has reach the limit of puff at around 60mph. And 70 is only a dream.

A better bet is a bigger engine.

I think this thread is due the Power Band discussion now.
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Scootaloo]