81' GS 450t starting and idling issues.

[Mr Rogers]

To start i'm new to riding and this is my first bike (i know the old bikes are more work but they look so good its hard not to want one!).
So i got the bike about a month ago and it ran alright.

Then it started having some issues where it would die at about 30 mph when i was coming to a stop light. for a little while i had to shutter the throttle to keep the bike from dying on me while i was slowing. but i would idle fine once i was actually stopped.

then after a week or so the bike would die even when i was trying to keep it running with a little more throttle.

now the bike wont start with the electric start. It seems like there might be some connection issues but really i don't know a lot about bikes.

so what do you think i should do now?

Thanks in advance

Mr. Rogers

 

[rlong74]

Welcome to the GSR and welcome to the joys and sorrows of owning a 30year old bike.
I can't speak to exactly what's troubling you but I can say that there is a megaton of useful info here that the search button will reveal.
I would recommend getting yourself a service manual and doing all of the preventative maintenance that may not have been done over the years. Also the electrical systems are notorious on these old bikes. So going through and cleaning or replacing all your electrical connections is advisable. Cleaning the carbs thoroughly i.e. taking them apart and dipping them in carb cleaner. I could go on and on but I'm sure some of the more experienced folk will be along to shine some light.
By the way we really like pictures here so if you got any post 'em up.

 

[apopleptic]

Welcome to the forum. Where are you located? You should update your profile because there are people on here from all over the world. maybe someone would be local to you.

There are alot of places to start looking for issues with an old bike, I started recently going through a similar experience.
First place I checked on mine was the spark plugs. easy to check, easy to replace. Of course it could be a bunch of other things. a bad igniter, dirty air filter, dirty carb, bad intake o-rings or boots, air leaking around the airbox, improperly adjusted carb, bad gas, and those are just some of the things I've gone through in the last few months.
Good luck and keep us posted =)

 

[s0nia]

Hi and snap, we have the same bike. I cant help on the technical issues you are having, but just wanted to say hello. I wonder what colour your is? Cant wait to see a picture of it, oh and welcome to the forum. Cheers Sonia.

 

[Guest]

Welcome to the forums Mr Rogers!

First of all, there are some absolutely necessary maintenance items to tick off as the other guys have said.

- Valve adjustments
- Carb cleaning
- Air intake system check
- Charging system check
- Tyre age check
- Front brake hose check

Take note that these bikes are 30 odd years old and a lot of PO's didn't cover off all the maintenance that they should've...

By what you're saying, it could be that the charging circuit is fried so it's basically running your battery down over time. When the rev's are up it could be generating enough voltage to keep the sparks happening, but when it drops down in the rev's it's not generating enough voltage for that to happen, and now the battery's too flat to start it.

On the main GS Resources page is a link to the Garage section and the Stator Papers, and they will tell you how you can test for that.

Alternatively, it could be the carbs needing cleaning and it could be starving for fuel if the carbs are blocked.

I'd also suggest you pop up a hello thread in the GS Owners forum so that way a certain BassCliff can find you and give you your mega welcome which has so much helpful information in it it ain't funny...

Oh, and as Sonia said, we like to see pic's of your ride

 

[Mr Rogers]

thanks for all the welcomes!

thanks for all the welcomes!

Sonia my bike looks just like yours, only black
I just ordered a manual off of amazon (7 whole bucks!) so that should help when it gets here.

I pulled the seat off and checked the air filter. it seems ok, not too dirty or anything but i didn't want to wash it in case it needed a special re-oiling process or something. I've heard that those older foam filters need to be re-oiled or replaced altogether.

I'm going pick up a new battery here pretty soon just so i can start the bike without pushing it.

The first thing i thought to check for the dying problems were the carbs so i'm going to check that as soon as i get the new battery in.

I'm not sure if this is also the carbs or not but for some reason my bike will idle normally just above 1k rpms until it warms up then i wont go below 3k unless i shutter the throttle.

Throttle cable? dirty carbs? (both)

Anyway. thanks everyone for the help i'll keep you posted on how the work goes.

 

[Guest]

Sounds like you've got the typical old GS dirty carbs/poor air intake situation going on, which means not running smoothly and "hanging idle" type symptoms.

The air filter needs to be oiled, and any engine oil will be good for it. Not wringing wet, just damp all the way through.

Air intake issues include the air filter not being oiled, air box not sealed up properly, carb to air box boots not sealing properly, cylinder head to carb boots not sealing properly, and the O ring in the latter boots being old and brittle and not sealing properly.

That's just a start anyway... and I definitely recommend a full and proper carb clean by soaking in carb dip overnight etc.

 

[Mr Rogers]

when i pulled the airbox cover off and checked out the filter the seal was partially missing on the outer intake section. Do i generally have to find a substitute seal or are there places i can buy these seals new?

 

[Mr Rogers]

actually, scratch that. Basscliff pretty much has all of my questions in one single page! carb rebuild, and air box sealing wow! well i guess there are many contributors but Wow! I could probably pull this bike to pieces and rebuild it with his website!

 

[apopleptic]

actually, scratch that. Basscliff pretty much has all of my questions in one single page! carb rebuild, and air box sealing wow! well i guess there are many contributors but Wow! I could probably pull this bike to pieces and rebuild it with his website!

There are alot of us that I think are dong exactly that

 

[Guest]

actually, scratch that. Basscliff pretty much has all of my questions in one single page! carb rebuild, and air box sealing wow! well i guess there are many contributors but Wow! I could probably pull this bike to pieces and rebuild it with his website!

You sure can! You can also do LED replacements for your gauge lights, swap out fork springs, replace your R/R with a you-beaut Honda/Shindengen one, use a relay to get good voltage straight to your coils, and a heap of other potentially worth while modifications to make your GS better than new in some aspects...

 

[Mr Rogers]

"use a relay to get good voltage straight to your coils"

Do you mean replace the electrical wiring through out? i'm about to pick up a battery today and i wonder if it's a good idea. If the wiring is bad it still may not work well with the bike and may not get the juice back from the alternator.

 

[2BRacing]

What Pete means is to look into doing the "coil relay modification" (lots of info using "search") using a relay. New, heavier wiring from the battery (via a fuse) delivers full battery voltage through the relay output to the coils, ensuring strong spark.

 

[Guest]

What Pete means is to look into doing the "coil relay modification" (lots of info using "search") using a relay. New, heavier wiring from the battery (via a fuse) delivers full battery voltage through the relay output to the coils, ensuring strong spark.

Yep, that's what I meant! I was just parroting some of the various modifications listed on BassCliff's site.

The coil modification is to work around voltage loss in the stock harness and connectors that you can't resolve by cleaning and fixing grounds.

 

[Mr Rogers]

I'm not even sure where all the grounds are on this bike...

I went and got a new battery to see if the bike would start up with a fresh one and sure enough it didn't.

After trying for a minute i decided it was probably better not to strangle the starter motor. but then when i tried it one last time just for the hell of it the bike made a loud pop sound and it looked like something blew out of the exhaust pipe!

I'm not sure how to test for compression problems but i feel like i should get the bike started before i try going into engine work.. any ideas on what might be wrong? spark plugs maybe?

John

 

[Mr Rogers]

How do you use a multimeter to test electrical continuity?

How do you use a multimeter to test electrical continuity?

So i got a multimeter from a friend so i could check and see if my spark plugs are getting the proper amount of power, the only problem is that i don't know how to use a multimeter..

Electricity is a technical skill i've never mastered and i really have little knowledge of what the interface on this thing even means!

Help?

John

 

[Guest]

For what you want it should be fairly simple.

There'll be a setting on there for measuring DC voltage, usually there's a 20 volt range which is good for 12 volt systems.

With the ignition and kill switches on (and clutch pulled in if you have the safety switch), you put the black negative probe to ground and the red positive probe to the orange/white wire on one of the coils. Repeat for the other.

Then check the voltage at your battery directly, again black to negative and red to positive.

 

[Mr Rogers]

Thanks pete,
I know it sounds stupid, but this simple direction helps a lot!
I'm going to go check right now!

 

[Guest]

Mate it's all good, the first time I used a multimeter I had no idea either...

 

[Mr Rogers]

ok so here is what i found.

The battery has 11.5v seems a little lower than i would like but it has been sitting for a couple days.

When i ground the black pointer and prod around with the red i found:

The orange and white striped wire that goes to the ignition coil on the both sides has about 10.5 volts.

i tested the inside of the spark plug cover and the right side had 5-6v and the left had 1-1.5v. There shouldn't be any power going through these until the ignition button is pushed right? i tested other wires around the bike and it seems like they are all responding with 10-10.5v

could it be the starter solenoid?

John