1980 GS 450 BOGGING, LOSING POWER, MAKING LOW RUMBLE and STALLING

[William P. Guff]

it'd be interesting to know what you did here:
"It began to make the loud bog, but I managed to pull out of it

I pulled in the clutch and kept the throttle and rpm's up. A delicate balancing act. If I didn't the bike would stall.

And when engaging the clutch, the bike would move, but sluggish at very high rpm. Suddenly it would get back to normal throttle, and I could operate it at regular shifting.


Today though I did the same thing as yesterday. But I limited my shifting not going beyond 4th.

I was able to get around with no problems until I tried to pass a truck.

This truck coincidentally happened to be my ex girlfriends Dads truck. Its a truck that I hadn't seen in years.

I consider the truck as a steed, and them as people, that I really would prefer to avoid. Not that they're bad people, its just to avoid the coincidental awkward run in.

Human nature.

So of course the bogging happened as soon I went to 5th gear for the first time all day, and tried to get past them. Thus sending me swiftly to a side street where the bike toiled to get me home.

The good thing was that because I couldn't pass the truck, they might not have seen me. So maybe I should thank the bog......

......this time.

Obviously it is a change to a certain gear that makes it happen. Last time it was 3rd gear.

Now its 5th.

And I was able to get around for 2 days without too many bogging instances. But the COUNTDOWN has begun.

Last time it was a few days living with the bog....but pretty soon when I started the bike the bog happened and I couldn't get out of the parking lot.

So the sequence begins again. Soon the bike will not go anywhere. After the football game was over I got on my bike and a block later it was bogging.

Any remedies? A cure all?

Or a procedure that might make it run regardless if the bog is not precisely identified.

Sort of like when a computer gets a virus and the whole thing is wiped and re installed?

 

[William P. Guff]

Well today I tried the same procedure that I tried the first time this happened.

Today,though, the results looked promising.

I unscrewed the carb bowls, and drained the gas in them. I then added to the gas tank the Star Tron additive that my mechanic gave me the last time this happened.

So I tried to start the bike after this and no luck. After about 25 or so no starts, I began to adjust the idle screw. Then it started.

I took it around the block but the bogging wasn't quite resolved. Plus the rpms were not stable and immedialey dropped to stall as soon as I loosed throttle.

So I pulled in the lot and put it on center stand and proceeded to loudly take it through all speeds trying to force the gas and Star Tron through.

The pipes began smoking from chain lube drippings, so I just parked it for a few hours.

I then came back out and tried to start the bike several times. Each time adjusting the idle screw until the rpms stabilized and the bike actually idled.

I took it around the block and immediately noticed that the Star Tron was doing what it was supposed to do and I felt that the bike was actually running well.

I then took it on the hi way for about 1/4 mile and it did ok until I turned off to turn around. I put it in 2nd and it bogged for a second, but it went right away.

So tomorrow I hope it can get me around town. Ill post results hoping someone will give me advice based on the symptoms that Im describing.

 

[Big Rich]

I'd like to point out: it's not a problem with what gear the transmission is in. Transmission problems are completely different than what you are describing. The engine itself is working just as hard at 4000 rpm in 3rd gear as it is at 4000 rpm in 6th gear (relatively).

What size jets are in your carbs now? Any shims under the needle clip? Air / fuel mixture screw still at the stock setting? Float height set to the stock setting?

What all this boils down to is this: somebody has to work on your bike. It is almost 34 years old now. If you don't want to work on it, and your mechanic doesn't want to be bothered with it, then you should probably sell it to somebody who is willing to do the work to keep it on the road.

 

[Guest]

Things I can think of that could be disturbed by some additive to the fuel and draining the float bowls...

- Rust in the tank.
- Inline fuel filter between tank and carbs that isn't flowing properly.
- Faulty fuel tap/petcock that isn't flowing properly.
- Improperly cleaned carb's, or carbs being fouled after being cleaned by rusty/dirty tank or bad fuel.

Also, when you drain your float bowls, you will need to prime your carbs before trying to start the first time, otherwise you will experience what you did where it will take a long time to be able to fire up. Priming the carbs lets fuel into the float bowls without needing the vacuum to open the fuel tap.

Your fuel tap will either have a PRI position or it will have no PRI position but a brass flat head screw beside the tap. If you have the screw, turn counter clockwise a couple of turns to open it up, wait 30 seconds, then tighten it gently again. Carb's primed.

I will also give Rich's comments a +1 on this... either find a good mechanic who likes working on these old bikes and has the patience for it, or learn to do it yourself, or get a different bike.

Most mechanics won't be interested unless they've been working on these for many years and like the older bikes.

Most people on this forum have learnt to wrench themselves, even if (like me) they are not mechanically minded and have never done so before...

 

[Gorminrider]

pulled in the clutch and kept the throttle and rpm's up. A delicate balancing act. If I didn't the bike would stall.

see, to me, this sounds like a cylinder has dropped out...

And when engaging the clutch, the bike would move, but sluggish at very high rpm. Suddenly it would get back to normal throttle, and I could operate it at regular shifting.

and this sounds like it kicked back in. But I'm just a brain-in-a- bottle on the internet with no fingers to feel or eyes to see what you are.

I hear what you're saying about the gear-shifting causing it...I am thinking though that it's not the gears themselves(or, I hope not!)- I'm thinking it's the change of throttle during the shift....and that's about the carbs,or even the spark...perhaps the spark advance mechanism is sticking- it's rev-dependent and it getting stuck would lose power. It's easy to inspect, too.

 

[esmithers]

Sounds to me that you have coils or coil that is breaking down (thermal) i have had this happen before and it makes diagnosing problems a hassle look into getting some decent used or new coils and see how the bike runs. I would also look at changing the plug wires and cleaning up the contacts in the plug boots

 

[William P. Guff]

Sounds to me that you have coils or coil that is breaking down (thermal) i have had this happen before and it makes diagnosing problems a hassle look into getting some decent used or new coils and see how the bike runs. I would also look at changing the plug wires and cleaning up the contacts in the plug boots

Thanks for all the suggestions. I'm taking it all into consideration. But today I took the bike out for about a 8 mile ride. Maybe 4 miles to destination parked, then 4 miles back.

I never took the bike beyond 4th gear though, and it got me where I needed to go.

Now my mechanic really doesn't have a problem working on the bike. And he does specialize in older Suzukis and Japanese bikes. He does have a lot of other responsibilities, though, as he runs the state MSF course.

So again thanks for the suggestions. Ill print this page out and give it to him when I get the bike serviced next.

 

[esmithers]

Did you make any improvements on the bike on getting it to run correctly and stop bogging down