Carb? TDC?

Question

I cannot start my bike, i suspected the battery but the battery is now fine.. I suspect it to be the carb!

Mainly because the it has been left standing for some time now and i may need to overhaul it.

But before i do, What do you think could be wrong?

Basically, The bike is a kick-start, 1980's single cylinder Suzuki (recently re-built)

I have only one concern with the way it was re-built and that is the TDC position, Would this have major effect on the bike starting, it has good compression but i am unsure of how to get this TDC (top dead centre) position? Would i have to re-build the engine again?

Any ideas, comments, suggestions very much appreciated! Thanks!!

Does have spark

Bike is 2-stroke

Has magneto and has breaker points

Was running when left but since taken down to frame and built back up..

Answer 1

Always give year, make, engine size and model # when asking questions. We need all of that info to give an informed answer.
2 & 4 stroke engines are different.

Answer 2

You say it is a 2 stroke so you should have TDC correct.

I agree, if it has a strong spark, it is likely fuel related.

The Carb(s) on these small engines have extremely small passages. If they are allowed to sit too long, the fuel can dry up leaving a residue which can plug these passages.

To be sure. Attempt to start the motor. If it doesn't start after several attempt, it should flood. Remove the spark plug(s) and see if they are wet. If they are wet, you are getting fuel and you need to look elsewhere. Maybe ignition timing or bad gas. If they are dry, you are not getting fuel to the engine and it will not start.

If it is not getting fuel, rebuild the carb(s). Make sure all of the passages are clear. Drain all of the old gas and replace with fresh gas.

If you already rebuilt the carb, you may need to tear it down again and check your work. Maybe the float is set wrong or sticking.

Next time, if the engine is not going to be started for longer than a couple months, add a fuel conditioner to the gas. Fill the fuel tank full so you don't get rust inside the tank. Close the gas valve on the fuel tank and run the engine until it quits to remove all of the fuel from the carb(s). Your bike can set for a year without any problems.

Answer 3

I agree it sounds like a fuel issue, assuming it turns over (the piston hasn't siezed in the cylinder) and the reeds aren't sticking (they have flat reeds instead of valves to control the fuel flow into the combustion chamber).

Clean the plug, set the gap correctly and a few drops (not too much!) of 2 stroke oil down the bore to make sure it's moving freely.

I'd recommend "Quik Start" or "Easy start" rather than wd40 to spray in the carb as that has volatile ethers and gives a bit more of a boost to the fuel mix. They also act as a good solvent for removing varnish from the carburettor.

Answer 4

A few things I would check: (in no order)
- Get a strobe light, that will sort out your timing (TDC)
- Drain and put new fuel in, petrol goes off
- Check the 2-stroke lines for clogging (assuming you don't direct mix in to tank) otherwise ... POP!
- Check (blow through) the jets in the carb
- Check/Renew plugs
- Check/renew points (better still fit CDI)
- Tkae the plug out and connect to HT lead, put on outside of cylinder to see if you get a spark

Ride Safe

Answer 5

sounds like you have a fuel issue due to the 2 cycle oil gumming up the carb while sitting. To varify this spray some wd-40 into the carb throat then try starting it. if it's pulling the fuel into the engine it should briefly start and then die. if so it's time to clean the carb

Answer 6

this might sound silly but look at your fuses sometimes when unhooking the wireing to take out the motor wires get pinch and could short out something