GN125 probs

[Nik P]

A mate of mine bought my old GN125 a while back and having just done
his CBT wants to start riding it. Trouble is, the GN has other ideas.

It's starts and idles OK on the stand, but when you actually try and
ride the bugger it loses all power and dies. It then won't fire apart
from the odd exhaust-full-of-fuel type bang. If you leave it for a
bit and try again the whole process repeats.

The carb has been stripped and cleaned and it doesn't appear to a fuel
issue. The coil has been replaced and my next step is to phone round
the breakers looking for a CDI and/or reg/rec. If it's not either of
those I'm guess I'm looking at some twatty loose connection or short
somewhere.

ATM I'm inclined to think it's the reg/rec as I also noticed that both
clock illuminators have blown. That said, I haven't had a chance to
get multimeter on it to check yet.

If any of the UKRM spanner wielders could make any suggestions or at
least let me know if i'm barking up the correct tree with the reg/rec
or CDI i'd be most grateful.


TIA



--
Nik
CB500

[tallbloke]

Nik P <nikUNDERSCOREphillips@hotmail.com> wrote in
news:o6d8u0945r61tnheic2mpap0qk40oo40iv@4ax.com:

> A mate of mine bought my old GN125 a while back and having just done
> his CBT wants to start riding it. Trouble is, the GN has other ideas.
>

Start with cheap fixes like a new plug. Sounds like spark breaking down under
load to me.

Is it on standard air filter? Try removing it and see if it'll rev more.

HTH


--
tallbloke
Tasmin350i MatchlessG80
BONY#1 DIAABTCOD#8 OSOS#27 SKA#3

[Nik P]

>Start with cheap fixes like a new plug. Sounds like spark breaking down under
>load to me.
>
>Is it on standard air filter? Try removing it and see if it'll rev more.
>

It's had a new plug, as you say cheap fixes first.

It's the standard filter. Another guy who had a quick look at it
recommended this but for some reason I dismissed it. I guess I was so
sure it was electrical. Now I'm intrigued, what will it prove if it
runs OK without the filter? Shirley the carb should be set up so that
it would run best when the filter is in place?

I not able to get to the bike until later in the week but I'll try it
and let you know what happens.

--
Nik
CB500

[Nigel Eaton]

Using the patented Mavis Beacon "Hunt&Peck" Technique, Nik P
<nikUNDERSCOREphillips@hotmail.com> typed
>
>>Start with cheap fixes like a new plug. Sounds like spark breaking down under
>>load to me.
>>
>>Is it on standard air filter? Try removing it and see if it'll rev more.
>>
>
>It's had a new plug, as you say cheap fixes first.
>
>It's the standard filter. Another guy who had a quick look at it
>recommended this but for some reason I dismissed it. I guess I was so
>sure it was electrical. Now I'm intrigued, what will it prove if it
>runs OK without the filter? Shirley the carb should be set up so that
>it would run best when the filter is in place?

*Best*, yes. But if your symptoms were being caused by a blocked filter
it'll run a lot better with no filter at all.

Mined ewe, a filter that's blocked that badly should be obvious to the
eye.

--
Nigel - Manufacturer of the "Champion-105" range of rearsets

WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41
ZZR1100, Enfield 500 Curry House Racer "The Basmati Rice Burner",
Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big"

[tallbloke]

Nik P <nikUNDERSCOREphillips@hotmail.com> wrote in
news:lmj8u05r4p9rkpnu8re3u16roolehc3838@4ax.com:

>
>>Start with cheap fixes like a new plug. Sounds like spark breaking down
>>under load to me.
>>
>>Is it on standard air filter? Try removing it and see if it'll rev more.
>>
>
> It's had a new plug, as you say cheap fixes first.

Could be a duff plug from new, try a known good one.

ALso check it's charging ok at higher revs by sticking a voltmeter across
the battery while it's running. You should get around 13.6 - 14v. If it's
dropping to under 12.5, the cdi unit may fail to time the sppark
correctly.

>
> It's the standard filter. Another guy who had a quick look at it
> recommended this but for some reason I dismissed it. I guess I was so
> sure it was electrical. Now I'm intrigued, what will it prove if it
> runs OK without the filter? Shirley the carb should be set up so that
> it would run best when the filter is in place?

Yes, but if the filter is clogged it'll strangle the engine and it'll
overfuel, hence the backfire and flooding. That would fit with having to
leave it a while before it'lll restart. Repeated flooding will also knack
the plug...

HTH

--
tallbloke
Tasmin350i MatchlessG80
BONY#1 DIAABTCOD#8 OSOS#27 SKA#3

[tallbloke]

Nigel Eaton <nigele@rcav8r.demon.co.uk> wrote in
news:ojdahyp7LF5BJwZq@rcav8r.demon.co.uk:

> *Best*, yes. But if your symptoms were being caused by a blocked filter
> it'll run a lot better with no filter at all.
>
> Mined ewe, a filter that's blocked that badly should be obvious to the
> eye.
>

Depends. Some filters can start to disintegrate and block themselves.
Unlikely but worth a try though.

--
tallbloke
Tasmin350i MatchlessG80
BONY#1 DIAABTCOD#8 OSOS#27 SKA#3