Suzuki 2 Strokes

Hi
I've just fixed the gear lever spring and was ready to start her up after at least 8 months of non running.
Have done the ignition timing (Newtronic).
Bike starts first time on the choke but runs VERY rough (seems like not running on three, based on the amount of smoke belching out of the pipe No 3).
Can't accelerate. The moment you open the throttle it dies.

what am i missing? (Apart from two marriages and god knows how many years of my life trying to get this 380 ro run well lol)

ALSO, to set my mind at rest and to eliminate timing - please can the members tell me about the marks on the small crankshaf cog, visible when the side cover is off? Can i guess that the middle one is TDC and one of the outer ones is BTC no? (I didn't use these as a reference although i don't know why people don't use them as a reference).

MJ in Beirut

1. Check the newtronic ignition has all three sensors correctly positioned. Recently came across a Newtronic ignition on a GT250 that was so badly manufactured one of the sensors only worked intermittently due to the interrupter only half covering the optic every time it rotated.
2. Check that you have a good seal on the ignition rotor cover. Newtronic works using light, it needs to be in the dark.
3. Check you have good fresh fuel.
4. Check you have three good clean, correctly gapped, spark plugs fitted (do not wire brush them clean. This damages the spark plugs and will seriously shorten their lives). If they are very badly oiled, throw them away, you will never be able to reliably fix them.
5. Drain the crankcase chambers by removing the three bolts (if a lot of oil drains out then you may have defective CCI valves)
6. Turn your attention to the fuel supply. Is it getting through or is the strainer in the tank blocked? (if you don't have one fitted, fit an inline fuel filter. This will save you lots of grief later on)
7. Check you have good compression on all three cylinders.
8. Check the condition of the air filters. Clean and oil the foam. If they are crumbling, replace them.
9. Remove, strip and clean the carbs thoroughly, blowing them out on a high pressure air line or jetwash. Upon reassembly, check carefully the float levels and set correctly. Also check the condition of the float valves, needle jets and everything else. If worn, replace them. Synchronise the carbs carefully.
10. While you have the carbs off, check the rubber intake pipes and also vacuum and fuel pipes for cracks.
Hopefully that should get your bike running sweetly, because I can't add any more checks to the list. I can't count over 10.
Good Luck

Lots of good ideas there. The oil is probably from weeping check valves, so drain the crankcases (#5).

Poor running suggests blocked pilot jets and passageways so strip and clean the carbs and dump any old fuel and replace with fresh.

Since it has sat for a while, it's worth going down that list and check the exhausts for baffles clogged with wasp nests etc and the air filters for signs of rodents.

tz375 wrote:Lots of good ideas there. The oil is probably from weeping check valves, so drain the crankcases (#5).

Poor running suggests blocked pilot jets and passageways so strip and clean the carbs and dump any old fuel and replace with fresh.

Since it has sat for a while, it's worth going down that list and check the exhausts for baffles clogged with wasp nests etc and the air filters for signs of rodents.

I forgot about the pipes. A good idea! I also forgot to mention that the symptoms suggest lean mixture so yes the carbs may be the best place to start.
P.S. Useful for setting the timing

and useful link for Service manual
http://www.3cyl.com/mraxl/gt/manuals/gt380man/index.htm

sportston wrote:1. Check the newtronic ignition has all three sensors correctly positioned. Recently came across a Newtronic ignition on a GT250 that was so badly manufactured one of the sensors only worked intermittently due to the interrupter only half covering the optic every time it rotated.
2. Check that you have a good seal on the ignition rotor cover. Newtronic works using light, it needs to be in the dark.
3. Check you have good fresh fuel.
4. Check you have three good clean, correctly gapped, spark plugs fitted (do not wire brush them clean. This damages the spark plugs and will seriously shorten their lives). If they are very badly oiled, throw them away, you will never be able to reliably fix them.
5. Drain the crankcase chambers by removing the three bolts (if a lot of oil drains out then you may have defective CCI valves)
6. Turn your attention to the fuel supply. Is it getting through or is the strainer in the tank blocked? (if you don't have one fitted, fit an inline fuel filter. This will save you lots of grief later on)
7. Check you have good compression on all three cylinders.
8. Check the condition of the air filters. Clean and oil the foam. If they are crumbling, replace them.
9. Remove, strip and clean the carbs thoroughly, blowing them out on a high pressure air line or jetwash. Upon reassembly, check carefully the float levels and set correctly. Also check the condition of the float valves, needle jets and everything else. If worn, replace them. Synchronise the carbs carefully.
10. While you have the carbs off, check the rubber intake pipes and also vacuum and fuel pipes for cracks.
Hopefully that should get your bike running sweetly, because I can't add any more checks to the list. I can't count over 10.
Good Luck

Bloody brilliant. In fact i drained the lower chambers before i read your top ten. I found that there was considerable amount of oil AND gasoline down there which just made it impossibe for the pots to fire. i can't work out how my carbs are weeping gas slowly into the chambers. damn annoying.
but thanks for the list. very useful

MJ

I just edited previous post. Hope the extra info is of some use to you.

Ramjam wrote: Bloody brilliant. In fact i drained the lower chambers before i read your top ten. I found that there was considerable amount of oil AND gasoline down there which just made it impossibe for the pots to fire. i can't work out how my carbs are weeping gas slowly into the chambers. damn annoying.
but thanks for the list. very useful

MJ

You're welcome.
Gas and oil in chambers can be due to leaking CCI check valves and poorly seating carb float valves.
You can replace the CCI check valves with Kawasaki ones. Search for related posts on here for part numbers and advice on how to do this.
Carb float valves should be checked and perhaps replaced if showing a wear ridge and failing to seal despite float height being set correctly. Make sure the floats are not bent or damaged. Check out the manual in link on previous post for setting up this.

Wow,
That seems like a pretty large tolerance for the ignition timing. My Haynes manual states my M model should be set to 2.3mm BTDC unlike the 3.0mm BTDC for the rest of the GT380 models as shown on the above service manual page, and I don't know why. My problem is I'm struggling to get 2.3mm BTDC as the points back plate won't rotate far enough before hitting the end of the slots. I can set the timing to 3.0mm BTDC with no problem. Should I just set it to 3.0mm ?
Regards,
Glyn.

according to THE BOOK gt380 should be 24 degrees or 3mm btdc when it fires once it's up and running get a strobe on it, the crankcases being full of mixture might just be for the amount of times it's sucked mixture through and not fired it. it's also probably in the exhaust system, so before you blow the garage up you need to empty all the unburnt fuel out
cheers, dd.

Service bulletin Specification-4 lists the variations: http://www.ozebook.com/compendium/techb ... %201-5.pdf
Its 24 degrees for 72/73 & 21 degrees for 74+.

Does anyone know if Suzuki changed the timing marks?

Glyn.G wrote: My problem is I'm struggling to get 2.3mm BTDC as the points back plate won't rotate far enough before hitting the end of the slots. I can set the timing to 3.0mm BTDC with no problem. Should I just set it to 3.0mm ?
Regards,
Glyn.

Your problem could be solved by removing the clutch cover and turning the rotor 1 tooth round to give you the necessary adjustment. Your metal pointer is probably slightly bent, thus causing you to get the timing gear one tooth out and giving you a lack of necessary adjustment on the ignition base-plate.

Two easy options for getting 21 degrees:
1) elongate the slots a little
2) points gap is nominally .014”. But the allowable is .012 to .016. You may be able to get 21 degrees by varying the gap a bit.

jabcb wrote:Two easy options for getting 21 degrees:
1) elongate the slots a little
2) points gap is nominally .014”. But the allowable is .012 to .016. You may be able to get 21 degrees by varying the gap a bit.

He doesn't have points. It has Newtronic ignition

if it only idles with the choke on i would check and see if the pilot jets are plugged

Indy650 wrote:if it only idles with the choke on i would check and see if the pilot jets are plugged

Yes +1 on that. Though you may notice it had already been suggested that he strip and clean the carbs.