GT125 starting issues

[fastcaprinz]

Hello everyone,

Starting issues please read and reply if you have a suggestion.

74 Suzuki GT125 (has been sitting for a while)

Flushed fuel line and peacock (fuel rate checked)
New Battery
Cleaned carbs (3 of the 4 jets were blocked)
Floats levels were fine and the air/mix screw was in factory setting 1.5 turns
2 new Spark plugs
New trans oil and 2 stroke oil (whats it called - oil injection system - posi-injection?)

Bike started and ran fine for a few rides up and down the road, but when I changed back to first gear to turn around the bike would stall, kick her over again and started fine. The next ride she would die and only with a push start she would start again. The third and final ride she would not rev-up at all.

Since then I have done the above work and I still cannot get her started!!

Checked spark (all looks ok) and it seems the fuel is getting through cause the plugs become wet (moist)

[yeadon_m]

Though the battery is new, I would check its staying at a good state of charge - do you own an Optimate smart-charger or similar? the bike won't keep it charged just a few mins up and down a garden.

Points: you don't mention those. May be worth checking they are clean, non-pitted and set correctly (gaps and timing).

Does sound carb related though, despite your work. I would have the carbs out again and see if any bits from a potentially rusty tank have been disturbed and are now blocking your pilot jets or slow circuits again! Did you flush out the fuel tank? what does it look like down the filler?

Oh, and I'd evict that Peacock. Definitely not a stock part, though folks would fit anything back in the day, just to show off )

Cheers,
Mike

[Coyote]

Does sound carb related though, despite your work. I would have the carbs out again and see if any bits from a potentially rusty tank have been disturbed and are now blocking your pilot jets

+1 Clogged pilot jets.

[sportston]

Sounds like carbs to me too. Hard to tell from here though. Have you got an inline filter? If not you could just be sucking up crap from the tank.
Step 1
Fit inline filter
Step 2
Strip the carb completely, clean and blow out on a high pressure airline (blowing with your mouth and a piece of rubber pipe doesn't work 9 times out of 10)
Step 3
Reassemble carb carefully, making sure to set the float height correctly and that all parts move smoothly and freely.
Step 4
Put carb back on bike, open tap and try to start her.

May also be worth checking the airfilter isn't clogged and that the plug isn't oiled up due to over-oiling.

[Alan H]

A peacock can cause all sorts of problems when showing off - they taste good tho'.

[Vintageman]

The science of bluffing -> http://www.rsvlts.com/2013/02/08/the-sc ... fographic/" onclick="window.open(this.href);return false;

Bike could be either carb or electric (e.g. batt low) as people have noted above.

Did the GT125 have E-Start like the GT185?

If so this may actually show better which it may be, given it works and spins the motor when batt properly charged.

[titan performance]

Don't think the 125 had the button start........is there a spark at the plugs?

[Suzsmokeyallan]

The GT125 did not have a press start feature, you might also want to consider having the carbs ultrasonically cleaned. Sitting for long periods can sometimes dislodge residue within a passage that partially blocks it and defies cleaning despite compressed air use.

[Vintageman]

if batt low plugs may still spark when removed for look see. One test is too see, how much an spark arc length could be drawn (bluish in color > ½” long, nice sharp snap to it). All this is subjective though and best get volt meter and measure battery voltage level to see how far under 12vdc it may be.

Else carbs like others have said should be looked at again very carefully.

All passages should be questioned and floats verified no holes (if brass like Gt185). Look for flooding out of overflow tubes on carbs, when petcock left on bike on center stand for example.

I always liked the looks of the GT125/185 engine cylinder/head design, Piston vertical. I see they have different stroke (43mm vs. 49mm)

[sportston]

Unless the charging system isn't working a low battery voltage shouldn't cause the bike to stop running.

[Vintageman]

Unless the charging system isn't working a low battery voltage shouldn't cause the bike to stop running.

.

It can and worse when ridding slow and generator not helping as much.

I had this happen to me on Yam R5 when engine RPM slowed down and died, And, I could not start again. I was about 1 mile from home, hid the bike in bushes, came back with my truck and volt meter, batter was down in the 10.x volt range if i remember. The wire from generator broke if i recall... was an easy fix, recharged batt good to go.

The other thing with RD when it got hot (coils) it would run rough slow and plugs would foul. As long as rpm up a little no issue. Proved to be coils for got a new set off Economy cycle and perfect ever since even lugging.

So far never had Suz coil issue, that day is coming I suppose. Should plan ahead ->
http://www.ebay.com/itm/Suzuki-GT125-GT ... 99&vxp=mtr" onclick="window.open(this.href);return false;

I had it happen on my GT250, I was riding in daytime, lights on, suspect root cause battery was getting low. When I slowed down it was stalling. It stalled. I waited some time, changed to spare plugs and then it started again ( iwas a little farther away that time). I had to keep RPMs up to make it home. I think the issue there was I had too large head light wattage (35W one not 25W) and had been riding low / mid rpms for a long while. Or I had to add the extra gen lighting coil jumper... not sure now maybe both

These are cases when engine needs batt to start. Maybe it’s just my luck

[sportston]

Unless the charging system isn't working a low battery voltage shouldn't cause the bike to stop running.

.

It can and worse when riding slow and generator not helping as much.

I had this happen to me on Yam R5 when engine RPM slowed down and died, And, I could not start again. The wire from generator broke if i recall... was an easy fix, recharged batt good to go.

Which is exactly as I said, isn't it? lol. The charging system wasn't working.
Normally if a charging system is working ok it should generate plenty of voltage to run the ignition system.

[Vintageman]

The generator does work. They just don't work well low rpm and require batt for power (broken wire to/from batt) or when over loaded ( wrong wattage bulb, or ignition coil part way shorted or ....)

Electrical System- In my mind I separate it as generator (power source), Batt (power storage), and elec. loads (bulbs, ignition coil). So checking battery could tell you a lot even if gen. itself is working as designed.

If the above is what you were saying in your reply, sorry if miss understood you sportson.

Also fatscprinz said it was ok , the longer he road the worst it got and he was in first gear (running gen slow) and it died,
Still sounds like it could be something wrong with electrical system. from how he described I could not be sure.

Yes carbs could have gotten clogged up during that riding getting worse towards the end. If that's how it went

It would be nice to 100% be sure not something elec. When you think its elec. its fuel and visa versa.

[sportston]

Yes it could be electrical, charing fault or whatever. Worth investigating probably then.

[fastcaprinz]

Oh this bike is giving me hell!

Ok so I have taken on board everything people have said here.

I have cleaned out the tank (again) and checked the fuel rate before the carbs - all is good (free flowing fuel)

Spark has been interesting - I had good spark on both sides, then the next time I checked I lost spark on the right bank. They are brand new. However on the off chance it maybe spark plug I brought two new ones (good to have spares) The right bank came back but now dropped the left side and then finally no spark at all. Checked points and condensor all looking fine and voltmeter puts condensor at correct ohms.

O.k you say it is electrical - Checked battery everything fine there a healthy 12+ volts - so I traced wires from batt to key then on the way back to ignation it dropped voltage to 2volts?? "Horay" you say but no it gets even more interesting - a wire beside the voltage drop goes nowhere and it had 12v, so on the theroy someone before me had made a mistake?? I changed to that power feed.... but you guesed it no start

I am banking on the theory it is elecrical still, I have already pulled the carbs apart now 6 times and cleaned and checked float levels.

Question - could it be voltage regulator??

Question - could it be compression related??

Here are some Youtube videos that might help - first one is of bike running before issues - the next two is spark before I lost that too

https://www.youtube.com/watch?v=f3lSNj1XXV8" onclick="window.open(this.href);return false;
https://www.youtube.com/watch?v=21jxerCfxpI" onclick="window.open(this.href);return false;
https://www.youtube.com/watch?v=UD4SMyJLXxk" onclick="window.open(this.href);return false;