Suzuki gs350 goose running issue

[willydd]

Hi guys,

I need some help troubleshooting my goose (basically same engine as a dr350). i just brought it off a guy who had it sitting for around a year. The story goes that he brought it not running and ended up replacing the CDI and rewinding the stator then it was parked up. When i brought it i was told that it just had a blocked main jet from sitting for so long. symptoms are consistent with this; starts and idles fine just coughs and splutters above 1/4 revs. allot of back firing and pop from the carb above 1/4 throttle.

I have taken the card off and cleaned it. wasn't overly dirty. no improvement

I have fitted a spare carb i was given with it and still similar running. Although it does seem slightly more responsive with the different carb. It did have larger jets

Spark plug is new.

fresh fuel.

Because i completely swapped the carb with no major improvement i am thinking the bug could still be in the electrics... I read somewhere that if the voltage reg/rect is faulty and supplies over 14.5V the CDI cuts out? I measured mine and it started missing at around 14.3V... other sources i read said that the out of the normal running output of the reg could be up to 16V so not sure that there is any problem here.

please let me know if you have any other suggestions to try...

Cheers, Will

[Grumph]

Before doing anything else, have a look at the plug on the lead from the ignition pickup. I've struck exactly the same symptoms on several Suzuki singles with basically the same ignition. If the two wires are around the wrong way in the connection, the ignition will fire and run - but not advance.
Ideally the colours on both sides of the connection should match - but even if they do, ease the terminals out of the plug and switch them around - or jury rig a connection.
If this doesn't fix it, no harm is done.

[OddDuck]

It may also be worth checking resistance through the wiring loom between battery and the ignition components, on both the power supply side and ground. Check voltage between battery positive and the top of the coil - look at both dc and ac, you shouldn't get anything significant on either setting. If you do, there's a high impedance back to the battery.

[willydd]

thanks for the input Grumph and oddDuck.

I tracked the ignition pickup wires all of the way back to the CDI and colours do all match. I tried swapping them but could even get it to fire. I think my jury rigged connection was a bit too dodgy. I will get some proper connections and try again...

Although i think i was too quick to rule out the carb. I took it out for a proper run today on the second carb and did actually seem allot better than the original. Also i didn't pick up on this before but the misfiring is related to throttle position not RPM. it starts misfire from somewhere around mid throttle then the power comes back only at full throttle. Its possible the things just needs a good tune. The carb doesn't have a mixture screw so for that throttle range i guess I'm can play around with the needle height and see if that helps?

please let me know if you think I'm on the right track. I'm pretty new to all of this so really appreciate the help :2thumbsup