My 85 GS450 quit running on my last ride

[dennco2]

Thanks for helping to clarify those dangling female connectors ... that are not being used on MY bike and don't seem to be needed.

[dennco2]

I was working on my gs450 almost till dark today ... but had to take it out for a quick spin to see if it would run or blow up. I adjusted the mixture screws and finished adjusting the valves ... and as mentioned before I cleaned the ignition switch. I instantly noticed the engine idling smoother and would accelerate through the rpm range much easier. The best performance since I have had it by far! I revved it to 7,000 for the 1st time and it seemed to like it.

I won't know until I ride it longer to see if I have FIXED the ignition switch shut down issue ... just by cleaning it.

[dennco2]

No further progress on knowing if I fixed the ignition shut down problem ..... but I took it for another 20 minute ride and it didn't skip a beat. The hp/torque test came as I climbed a long steep grade in 5th instead of the usual 4th gear. Test again tomorrow and check my voltages and plugs right after the ride.

[dennco2]

I just got back from a motorcycle trip to Oregon with my other bike ... and finally rode my gs450 again on a little 5 mile ride for a late lunch. I ride over a large fairly steep hill and down the other side to my destination. Later on the return trip I had to stop for a stop light and the engine stumbled and died. I could not get a restart and pushed the bike for a U-turn back down the hill to attempt a compression start. Took 2 attempts but it reluctantly started so I reversed course again and headed up the hill keeping high rpms. My gas gauge showed I was low on fuel but not empty.

I made it home but my confidence in the bike reliability shaken again. When I 1st fired it up, I noticed my idle was slightly low so I adjusted it higher with the screw adjuster. Idle looked good at 1,400 cold (but no choke) but during the ride the bike did not want to slow down when I rolled off the throttle and then back at home I revved it up and the rpms would NOT return to idle .... so I shut it off at the ignition. One other problem I noticed is when riding the bike, I can see the lighted gear display on the dash flicker slightly ... not a steady display. Maybe the headlight and other lights are doing the same too ... but I have not noticed as yet.

So, my bike starts immediately with or without choke but won't keep running without full choke. After 20 seconds or so, full choke will cause the idle to rev out of control. Partial choke is fine at that point and no choke needed after say 1 minute. If I try to set the idle to a smooth 1,400 when engine is cold, it is close to revving to 3 or 4,000 rpm when warm ... with throttle at idle.

Seems I should set my idle way lower and hold more choke to keep it running when it is cold? Is a flickering light display on the dash indicate electrical or charging issues?

[SanderG]

Hello Dennco2,

The Idle problem is pretty normal as far as i know.
You should set your idle when the Engine is HOT, not when the engine is cold.

My bike for exemple needs +-10-20 sec of Choke ( half way ) when cold and after that I can ride it without choke.
When your engine gets hot it's normal that the idle will increase.
So when you allready set the idle to 1400 rpm when cold it will probably go to the roof when hot.

Normal idle is +-1200 rpm when engine is hot.

As for the flickering dash, I wouldn't know a direct answer.
But maybe you should look for loose contacts on your dashcables?

Kind regards.

[Brendan W]

Sounds electrical and you have found part of the problem.
What I do is start from the battery positive and open and clean each and every plug, switch, connector and fuse holder all the way to the headlight, bar switches, tail cluster, ignition pick up and back to the grounds.
The kill switch needs the same treatment as the ignition switch and the plug for the coil may look ok but hide corrosion of the wires inside.
Odds are on a machine that age that there is more than one component acting up and in the long run it's easier to take them all on over a period than try to guess. In their wildest dreams the guys at Suzuki never saw these bikes lasting this long.
If a bullet connector looks dodgy it probably is and you are better off getting yourself a good crimping tool and putting on new spade connectors there.
One short cut is to get the bike idling and start pulling at plugs, particularly the fusebox tail and see if you can get the bike to flicker or cut out by pulling at wiring.