Advancing timing = power increase?

[knockout_bar]

The timing on my 125 at the moment is wayyyy out. When it's idle-ing (1,500 rpm) if you leave it, the engine just dies and it boggs out when you try and open the throttle. You have to open the throttle slowly for it to rev up.

I know the above problem does NOT lie in the carburettor! I had the carb off two days ago, cleaned the jets put it back on and it didn't make any difference.

If I get the timing to the standard, is there any way I can advance it to get a slight power increase? You can get ignition advancing kits, but I don't really want to fork out £60 for one of those.

I'm thinking of getting a smaller back sprocket and a bigger front sprocket to get a bit more speed (I don't really like cruising at 7,000 rpm on a 4 stroke...). I really want to squeeze as much power as I can out of this beast. I think the bike has a lot more potential than it does a the moment (restricter in the downpipe which is going).

Anything I can do to the bike to give it a bit more kick? (It's embarrasing, my friends CG125 has more acceleration than mine, please help! )
____________________
125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee)

[Kickstart]

Hi

Advancing the timing does give you more power (generally), right up to the point you burn a hole in the piston.

Depends on the bike. Older RS125 then you just adjust the timing by moving the stator slightly. Most bikes you need to more the rotor. Believe you can get slightly offset woodruff keys to do this.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[knockout_bar]

Thanks,

The bike runs off the magneto, not the battery (the bike starts and runs with the battery disconnected). I think (hope) I can advance the timing by the stator.
____________________
125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee)

[stinkwheel]

If it is a copy of a Japanese 125 and has a CDI rather than points ignition, you will probably find there is an advance curve built in anyway. Even 1970's hondas had an auto-advance built in to their points systems.

If it were me, I would set the ignition timing to bang-on standard (assuming it is a points ignition, CDi ones are usually fixed timing anyhow). You'll just land up with the engine pinking and burning a hole in the top of your piston by advancing the ignition much more than they aready are advanced.

My last small honda 4-stroke used to redline at 11,000rpm so I wouldn't be overly concerned at a 7,000 rpm cruise. I sat my 1981 CB125 at between 9-10k rpm for a solid 250 miles a wee bit back and it never missed a beat. They tend to have a pretty short stroke which means high revs.

One more thing. Your problem sounds to me more like there is an air leak round the inlet manifold. Try spraying some EZ start over the rubbers when the bike is ticking over. If it revs up, you have an air leak.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[knockout_bar]

Thanks,

There is a rubber link/tube between the carb and the head, but the inside of the link/tube is metal.

My 1978 Kwak KE175 has electronic ignition (CDI), but the timing is set by the pulser coil (on the stator, under the magneto). So I figured that since my engine starts and runs with the battery connected, then you should be able to move the stator plate to advance/retard the timing.

When I put the carb back on the other day, I sealed the join with gasket glue. The bike misfires even sometimes at high rpm, not just at tickover.

Do you think the restrictor in the downpipe could be causing this? (I know it's there, I've had the pipe apart and seen it with my own eyes)
____________________
125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee)

[knockout_bar]

Another thing I should mention is that when I first got the bike, it started from cold (choke fully open) first kick. It now takes about 6/7 really hard kicks (choke fully open) to start from cold...
____________________
125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee)

[stinkwheel]

The way to 'dial in' the ignition timing on a fixed CDI ignition that I have seen is to first make a mark across the stator plate and the crankcase to allow you to identify the 'standard' position later.

Then take off the stator plate and slot out the screw holes that are used to hold it in place. When you put it back on, you should be able to rotate the plate around its axis to advance or retard the ignition using your mark as a datum.

The more you say, the more I think there is something more fundamental wrong with your bike. If it was running fine before and is now running crap, you want to sort that first before attempting to 'tune' it.

If I were you I would get the manual out and do everything listed under a major service. Restore everything to factory settings. I would also do a compression test.

Tuning an engine that is not running sweet as a nut to start with is a recipe for disaster, you will only exaggerate any problems you had when it was in a lower state of tune.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[knockout_bar]

[stinkwheel]

So I presume you have checked the following:

Fuel filter.
Fuel line.
Air filter.
Oil level.
Sparkplug.
Tappets.
Carb settings.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[knockout_bar]

[Kickstart]

Hi

Possible that the problem is just something like a dodgy coil.

The XL125 does not use the same engine as the CG125. The CG is a pushrod lump, the XL an OHC engine.

Often a starting problem is down to a weak mixture, sometimes caused by an air leak. Also possibly caused by carb adjustment of just rubbish in the carb.

By tappets he means adjusting the valves. If the valve clearances are too tight them you will have problems starting the bike, although it will probably get worse as it gets hotter.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[knockout_bar]

[stinkwheel]

[sudds]

[Kickstart]

[sudds]

Whoops mistake on my part sorry, But my friend does have a newer Cg with a OHC engine must have been swapped with a XL's engine.
Sudds
____________________
Aprillia Rx50 2000 model race tuned, Aprillia RX50 Racing Late 2004 Model and Suzuki RM 80 1989 model.