Powerbands and CGs

[Itxi]

Blue or Black?


On a more serious tone, is there any way to modify the powerband of my CG? I used to be able to do 60 with it no probs, well it was a slight struggle, but it still felt like the engine was pulling if that makes sense.

A few weeks ago a part of the carb somehow shook loose and when I put it back the powerband changed, I now have plenty of low-rev power and it accelerates like stink, but it'll now reach a maximum of 55 and the engine doesn't feel like it's really got any 'oomph' to it.

Now I have fitted a top-box and panniers in this time so I can understand how that may reduce the top speed on a 125, but it still feels like it has more low-rev torque than before.

I'm not trying to get more power out off it, just smooth out the powerband towards the higher revs.
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[Howling TerrorOutOfOffice]

First thing I'd do is check that the part that fell off has been replaced properly.

Next thing I'd do is realise that adding a full luggage system will make my 11hp commuter slow.
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[Itxi]

Part has been replaced fine.

I know the luggage is probably what's slowing it down, but is there any way to give it some more power in the higher revs to counteract the luggage? (need it for shopping)
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Hastings Direct, Scum you say?

[Alpha-9]

check your tappit clearances, should be 0.08mm I think

CGs are naturally a bit slow
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Fzr-600 1999

[Vincent]

[Itxi]

Cheers, I'll look into changing the rear sprocket, so long as I can get a cheap one.

I may open the engine up if I have a spare weekend, see if I can do any maintenance.
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Hastings Direct, Scum you say?

[_Iain_]

Gas flow & skim the head, bigger carb, get a realy lumpy race cam. Bigger bore barrel/piston, and a longer stroke crank too. Get it all setup on the dyno with an aftermarket mappable ignition.

Should make the powerband nice and peaky and largely useless. Might make somewhere around the 17hp mark though. I'd seriously question if it was worth it though
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Please be aware that the above post may be full of complete nonsense.
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[russell210276]

or replace your front sprocket go 1 up its easier and from what i read going 1 up on the front equals taking 3 off the read

[Rogerborg]

[Itxi]

Part 11, the main jet is what came loose.
https://cdn.bikechatforums.com/files/untitled_119.png

I just screwed it back in again. Didn't change anything else, taken the carb apart enough times to know where everything goes.

this thread may sound chavy, but I was just wondering if the powerband can be adjusted through tuning, not trying to up the power or anything.
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Hastings Direct, Scum you say?

[russell210276]

the power band or where the peak power is can be done by some engine tuning but your looking at bigbore kits and i think higher compression might play a part of shifting the power up or down aswell.

problem is the power band isnt like a 2 stroke or even vtec as with them 2 you no when you hit it i dont think theres much to be done to a cg as there is no aftermarket parts and plus its a pushrod engine doesnt make much power at the top due to valve overlap. theres more bottom end grunt than anything

[Itxi]

So not much I can do then, cheers for taking the time to reply.

I may look for a smaller rear sprocket.
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Hastings Direct, Scum you say?

[Rogerborg]

Oh, I had that too.

https://4.bp.blogspot.com/__DYtEEjm5wE/S27qgGcHuaI/AAAAAAAAAI8/Q9DUZX-bJho/s320/float-bowl-jet.jpg

How's your plug colour? Have you done a WOT plug chop?

I found on my CG-copy engined bike that upping the front sprocket by 1 and then 2 teeth gave more relaxed riding, but it didn't really increase the top end. Worth a fiddle for the price (under £5 a sprocket delivered), but it still sounds like something has changed in your bike to cause it to lose power.
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[Itxi]

Haven't done a plug chop yet, may do when I get a paddock stand (actually I wont because everyone knows the engine needs to be under load ) But typically the plug is fine, perhaps running a little rich but not massively so, and that could be the accelerator pump. (got given a later-version carb with the pump and thought I may as well put it on, but that was when I first got the bike)

Not sure what's causing the loss of power, could be the luggage but it's not just travelling slower, it does feel like there's less power from the engine.
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Hastings Direct, Scum you say?

[cb1rocket]

you can't do a plug chop on the paddock stand! engine must be under load.....

[Itxi]

As much as I have learnt over the past 7 months I still know very little
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Hastings Direct, Scum you say?

[Rogerborg]

Is there any chance that you've nobbled your needle? Again, I ask because I did that - after some fiddling with the height, I fumbled putting it back in, the clip worked loose and the needle was essentially only being held down by gravity. That resulted in running rich, decreased power, and increased fuel consumption.
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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

[Itxi]

I'll have a look when i head home, pretty sure the needle is fine but it's possible.
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Hastings Direct, Scum you say?

[DMCpro]

have you tried fitting new powerbands? take the barrell off and put some new elastic bands around the piston

4strokes dont have powerbands
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[symonh2000]

Take the engine out and fit a 2 stroke.
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Four strokes is two strokes too many.

[Kickstart]

Hi

If the main jet (and presume possibly the attomiser tube) has come out then it is possible that the needle has been damaged. Take the carb slide out and inspect the needle carefully.

All the best

Keith
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[sickpup]

[DMCpro]

[stevo as b4]

Compare a CG125 engine to a 125cc 4stroke lawnmower engine, and i think you'll find the CG has a nice pronouced power band probably in the 5000-9000rpm area. The CG isn't a dull bike and 11bhp has never been so much fun on a geared machine IMO.

I'll get my coat, but i always thought mine was quite nice and nippy around town, and so much less annoying than those 70cc race kitted scooter's that rev like a model aeroplane motor on Nitrous before you see any sign of acceleration in the slightest.

[el_oso]

of the few 125 bikes i have used i found that the cg was very boring. i found that it was better down the lower end of the rev range than the higher end.
the extra weight won't be causing a noticeable difference. what may be hampering your top speed would be extra wind resistance from extras you may have fitted. Even small changes in surface area of the bike against the wind can affect the top speed greatly, especially at higher speeds.
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