CG 125 lack of power/hesitation

[stonesie]

When I bought it there was a little cone type filter on it, that has been replaced with a standard airbox and a new filter element, oiled up like it says in haynes.


But now the bike is 10 mph slower and really struggles at the top of its rev range... Does some cracking backfires though on downshifts.

Any ideas how i can sort this without re-fitting the cone?

[N cee thirty]

see what the plug colour is

the other owner probably jetted the bike to suite the cone filter and now its back to normal too much fuel is coming through
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[stonesie]

The plug is pretty black, too much fuel being drawn through because of the bigger restriction from the standard filter

Much better then it running lean.


I've just been playing with the idle and ended up winding the pilot screw in about 3/4 of a turn, will test it in the morning and see how it goes

[N cee thirty]

you might aswell find what jets ment to be in the carb and make sure thats the one in,the air screw only changes the mixture on idle
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[stonesie]

Haynes makes no mention of what jet it should have, just that a slightly later version had modified jet to cure some running problems at certain throttle settings... But does not say what they were or how the modified parts differ

My next opportunity to work on it is either Sunday afternoon or Tuesday.



The throttle cable was very slack, might slacken it back off and see if that helps

[N cee thirty]

in my haynes manual for my 92 cg it says the jet should be size 90

can't see the carb being changed over the years tbh
____________________
'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[stonesie]

Now I have looked at the correct part (doh ) the BR-K should be a 95 and the later BR-S/T uses a 110.

[N cee thirty]

haha you should check the jet then to see if its right
____________________
'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[stonesie]

Problem is that I am working a looong shift tomorrow then have to be in Sheffield at 9am Sunday morning for an assessment, it's a free thing that the place I did my CBT with do to see how I'm coming along.

Will be having a chat with them about a DAS too... Suppose I will just have to keep her below 3/4 throttle.



Also i have been trying to track down a supplier for a re-build kit for the PD47F-A carb.... seems to be a bit of an oddball


Edit

After all that I have found some on Ebay of all places Roll on Sunday afternoon so I can get it apart and see what's what

[The Artist]

Hang on, you have a cone filter? As in the K&N style ones which are usually paper elements which you shouldn't oil because if you do, it will restrict air flow in and cause the engine to run rich?

First off, that filter is now ruined if you put oil on it. Only foam ones should be oiled.

[stonesie]

I oiled the foam insert in the standard air box, a brand spanking new insert at that as the old one fell to dust when I touched it.

The Cone is on the shelf where hopefully it will stay, it sounds like a blowing exhaust and attracts the wrong kind of attention (Chavs think its great ) In my opinion the standard air box sounds better and will be breathing dry air in wet weather.

[stonesie]

I've put the noise maker back on for now and it's a much happier bunny, but there's something really odd about that carb, the pilot screw is only open about 1/3 of a turn, if I open it much above half then the engine slows and becomes hard to start.

[stonesie]

One mystery solved, another discovered

The main jet is a 108, should be a 95 but would I be better fitting something like a 98/100? 108 is too big even with the little cone filter.
https://a.imageshack.us/img441/5674/dscf0089c.jpg


I did try to replace my chain and sprockets but the new rear sprocket simply would not fit, some digging has identified the current 44 tooth rear sprocket as being for a 2000/2003 CG125 Titan, they have a different PCD to the Brazilian.
https://a.imageshack.us/img261/4131/dscf0085k.jpg
https://a.imageshack.us/img441/272/dscf0086jo.jpg

But I did find a simplistic way of doing the wheel alignment using a wooden block, tie wraps and a length of copper pipe
https://a.imageshack.us/img441/9477/dscf0088f.jpg

[N cee thirty]

might aswell buy a few jets and see what feels right

lolz pretty clever way of doing the chain
____________________
'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[stonesie]

I didn't even measure it to cut it in half, just balanced it on one finger and cut it at the balance point, by chance the length was just about spot on


Edit

Just been and ordered a pair of jets, 98 and a 95 and got the bike running again, half a bloody hour of kick-start action before the sod got fuel through. Must get a squeezy bottle to fill the carb for when these jets get here (although the exercise is good for me, according to our lass)