!HELP! 1983gs450a Bogged down on the freeway at high revs

[zoso83GS450a]

Hey I was riding my 1983 450GA back to portland from up in washington last week and when we were just about 2 miles from home I sped way up to pass a big rig on my right and as i passed it the revs dropped quickly and then kept going for just a little while.....I thought she might stay at those mid to low revs and keep going but after a few seconds she shut off.

Now...I had to jump start the bike twice on my trip....but this was obviously just due to the battery being really old, because she started up good as new when attached to a good battery. She ran fine engine wise all day with two people on back for about 100 miles....and then died so close to home.

I have done my research and I thought it might be the vacuum problem with the fuel system so I let air in but still no go. We tried to jump start her again but now she just keeps trying to turn over.....rrruuur rrrruurrr rrrruuurr sound.

Is this something I can fix or do I have to get her towed somewhere... Thanks

 

[Nessism]

What kind of maintenance have you performed on this bike. It's hard to offer suggestions until we know what has been done.

 

[zoso83GS450a]

What kind of maintenance have you performed on this bike. It's hard to offer suggestions until we know what has been done.

I havent done any yet....I actually received the oil and filter I ordered the day after it broke down. other than that I was planning on checking all of the o-rings and the intake seals but the two I have already looked at looked surprisingly clean and crisp for possibly being 20+ yrs old.

The battery has been the problem with it however all it ever needed before was a jump. I pretty much was two days away from having it completely worked on up to reliable standards when this happened

 

[Nessism]

It takes a lot of work to bring a 28 year old motorcycle up to standards. Hope you can do the work yourself because it's going to cost a lot of money if you are going to pay someone.

 

[zoso83GS450a]

It takes a lot of work to bring a 28 year old motorcycle up to standards. Hope you can do the work yourself because it's going to cost a lot of money if you are going to pay someone.

Well it only has 4000 miles on it and has been owned by a retiree who kept it in an enclosed garage. The engine sounded tip top and she fired up just fine up until that day...and even with the battery dead she ran just fine..idled smoothly.

I have seen stories all over the web of people buying these GS bikes with their "bulletproof engines" with 20,000 miles, doing a little work, riding her hard and going till at least 60,000. It just feels to me like if this is some massive huge problem about 15-20 different indicators were incorrect or I completely missed the mark. And I'm green but i aint that green lol.

 

[Nessism]

Yes, the mechanical portions of the engine are bullet proof, but those 28 year old rubber parts in the carbs, petcock, brake system, etc are aged and likely deteriorated. Things like the brake system should be stripped down and cleaned out. The carb O-rings should be replaced, along with the intake boot O-rings. Also the valves should be adjusted and the charging system checked out. Lots of things to do if you want the bike to be reliable.

Good luck

 

[mike_of_bbg]

I doubt that there's serious internal engine issues. As Ed says, you need to get caught up on maintenance. Don't make him post the "top 10 newbie mistakes" link again!

In all likelihood your issue is either the ignition system or fuel mixture. Have you tried laying the plugs against the head to see if they're sparking? Are the plugs wet with fuel? What do they look like? You need to get a good battery before you do anything else. Your charging system might well be having issues and you have a "good" battery that's not getting charged. I have a "bad" battery and it cranks the bike just fine without a jump. Do you have a battery charger that can be set to 2A or less (never charge a motorcycle battery at >2A)?

Did you get your mega-welcome? The top 10 issues need to be addressed or at least verified to be non-issues. Valve clearances, carb cleaning, no air leaks, etc.

The vast majority of "professional" mechanics won't work on bikes this old. And if they do, they're probably not particularly familiar with the issues common to the GS line. The 450A is rare enough that even those would be scared to touch it. You'll spend a fortune, the work probably won't be good. You have a great resource here, use it and wrench. As Ed once said, "wrenching isn't for everyone". It's an old bike. It's going to need work. Either commit or bail. That advice is for your own good.

 

[zoso83GS450a]

Ok cool thanks very much for this input...I think I will for sure bring her home and set to work on her myself with the help of some buddies who know more than I. I do absolutely find this GS resource (pun intended) and BassCliffs site invaluable so I feel confident I can figure it out.

One last thing I worry about is my tool situation....I moved in the last year and dont have access to my father's or any friend's tools so I'll need to buy some....what really do I need other than the bikes specific toolkit, which is all there.

 

[Nessism]

You are going to need a bunch of tools, too many for me to sit here and try to list.

A good start would be one of those Sears mechanics tool kit starter sets. Will cost you a couple hundred bucks but give you are good starting point to build on. The fasteners on GS bikes are metric so keep that in mind while you choose a tool kit.

 

[mike_of_bbg]

This seems like a good starter set:

http://www.sears.com/shc/s/p_10153_12605_00933182000P?

Add a multimeter, in-lb torque wrench, and good screwdriver set. Some pliers. Stuff you should have. Battery trickle charger. Shim tool. Metric hex insert sockets (3/8").

That would cover about 95% of the work I've done on the bike so far.

 

[zoso83GS450a]

Thanks very much.....I will be heading to sears and looking around for this stuff. After the limited experience I have with working on cars I'm stoked to set out on this project. I will keep BassCliff's website and all your suggestions close at hand

 

[Nessism]

This place rocks for finding deals on everything, including tools... http://slickdeals.net/

Harbor Freight is also a good place. Their higher end line of hand tools is pretty darn nice in my opinion, and fairly priced.

 

[zoso83GS450a]

Just lastly as I am trying to put my priorities in order...This list is from the GSR welcome from BassCliff....I'd like to hope that the things I need to do to just get it running are things that dont require massive amounts of parts......seeing as how my bike was running fine for 400-500 miles when she bogged down..... and then go from there with the heavy stuff like carb rebuild or valve adjustment when I have the money to do so beginning next month. I have no other transportation I'm just a starving student lol.


SO what order should my repair list be in?




1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.

 

[cowboyup3371]

I personally would do things in that order although the carb to airbox boots may be hard to find and should probably go after 5 and 6.

 

[Nessism]

Just lastly as I am trying to put my priorities in order...This list is from the GSR welcome from BassCliff....I'd like to hope that the things I need to do to just get it running are things that dont require massive amounts of parts......seeing as how my bike was running fine for 400-500 miles when she bogged down..... and then go from there with the heavy stuff like carb rebuild or valve adjustment when I have the money to do so beginning next month. I have no other transportation I'm just a starving student lol.


SO what order should my repair list be in?




1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.

I'm not a fan of this list taken at face value.

1) Yes, agree
2) Only necessary to replace if the originals are cracked
3) Yes, agree
4) Only necessary to replace if the originals are cracked
5) Yes, agree
6) This is not an issue on the regular 450, but I'm not sure about GA model. Fix as necessary
7) Only necessary to replace if the original is bad
8) Verify spark and repair system as necessary
9) Check these caps and replace as necessary
10) Agree, no leaks

Also, please read this... http://www.thegsresources.com/_forum/showthread.php?t=171846

For your bike I'd do the carbs and intake boot O-rings right away. Check the air filter and make sure the airbox is sealing properly. Check the petcock to make sure it's functioning. Replace the fuel and vacuum lines. Valve clearances should be done too but that would be second priority because of the engines mileage.

Good luck and don't worry, these bikes are simple an as long as you are willing to learn and do what's necessary, you will get it sorted out quickly enough.

 

[tkent02]

Just a WAG, your petcock is probably not flowing quite enough fuel for the full power operation.

But yeah, you have to do all the other stuff.

 

[zoso83GS450a]

Ok that all sounds like stuff my buddy and I can tackle. The only two things i worry about are getting into carbs and valves but as the 10 newbie mistakes says i might as well tough it through and do all the work so i know what is not wrong.....i will pay special attention to the charging and fuel/air systems. Thanks i dont know what i would do with out this library of knowledge!

 

[Guest]

And you'll need an impact driver! Not sure if those starter kits include one or not, but expect to use one *a lot* if the sprocket cover and clutch cover etc. haven't been off for 30 years... better to invest in one of those than having to deal with chewed out philips heads...

 

[mike_of_bbg]

tkent02 might be right about your petcock. You can take your fuel bowl drain screws out and make sure there's a good amount of fuel in there. I might also suspect a gummed up cap vent or petcock strainer. You need to make sure your whole fuel system is clean: tank, petcock, fuel lines, tees, carbs. Even little chunks of rust are like boulders to the tiny passages in your carbs.

Just to follow-up on the tool part:

For most of your maintenance, you'll reach for your 1/4"-drive set with metric sockets from 6-14mm. Most stuff falls in that range. My oil drain plug is an odd sort of size like 22mm, though I can't be sure it's original. The set I linked to should have most of what you'd need, though I'm not necessarily married to Craftsman tools. Mine have lasted over 20 years and saved me thousands in that time.

Remember that this is not a car; it's a motorcycle with stuff threaded straight into aluminum! One of the most common issues is to over-torque bolts and strip threads. Most of the torque specs are in the 3-12 ft-lb range (36-144 in-lbs). Do a search sometime for stripped oil filter cover studs and see how common that is - or oil plugs. Torque wrenches may seem expensive but definitely can save you a ton in the long run.

For your valve check/adjust you'll need the above plus a gasket scraper and a set of metric feeler gauges that go down to 0.03mm.

Impact drivers are handy, though I've not needed the impact until I've gotten under the covers. The screws on your bike are soft steel JIS, or Japanese Industrial Standard, philips. It's different. Getting screwdrivers that fit well is a huge advantage. I have the Craftsman black impact driver set which is about $20, though I rarely need to put a hammer to it. The bits in that set are excellent and grab lots of screws that my other screwdrivers would strip in a heartbeat. Having a access to a dremel and vice-grips helps for the eventual stripped screws.

One reason mechanics usually refuse to work on bikes older than 10 years is the high risk that fasteners will break, strip, etc. and turn a profitable job into a loser. When it's your bike you have the advantage of being able to be patient. Some of your most important tools will be chemicals. Hit fasteners with PB Blaster well in advance of putting a wrench on them; let it soak in and do its work. Use anti-seize thread compound where steel bolts go into aluminum. Berryman's dip cans are great for the carbs. Dielectric silicone compound on those bullet connectors will help keep them from corroding after they've been cleaned.

 

[850 Combat]

.seeing as how my bike was running fine for 400-500 miles when she bogged down

How old was the oil in it? I think you said you never changed it.

Have you verified that fuel is available from the petcock? It is common for them to fail, and also to clog if the fuel tank is not clean inside.

Have you verified that there is spark?

You described a sound the starter made. Was the motor spinning slowly on the starter? If so, it may not be charging properly. If it isn't charging properly, the ignition will run out of sparks.

There is a lot you need to do in order to narrow down your search as to what the problem is.