1979 gs850 warming up tips?

[nicogarceron]

Hello Everyone,

I'm new in this forum and I'm trying to learn as much as I can of my newly acquired 1979 gs850g.
Si here goes my question, I know these machines are well known to take a long time to warm up... it tried to rev it up a couple of times and it just dies when I give it throttle. It does rev up normaly after a couple of minutes, but doesnt like to be rushed...) is there any way I can improve this? Also the choke tends to slide down by itself due to vibration while waiting for it to warm up... any trick to lock it up?.

Any help will be much appreciated!

Thanks,

 

[Steve]

First of all, how much of the (usually neglected) maintenance have you caught up on?

If the carbs are CLEAN and properly adjusted, you should be able to apply about half "choke" to start the bike, monitor it for a few seconds to make sure it does not race over 2500 RPM or so, put your helmet on, then RIDE. By the time you get into third gear, you should be able to turn the "choke" OFF. There should be none of this "cold-blooded" or "long time to warm up" nonsense.

Part of the problem is because of improper starting technique. While on "choke", if you try to rev it up any, you are defeating the enrichment circuit that comprises the "choke", meaning that it will bog down or even die. Let it warm up just a bit (about the time it takes to put on your helmet) and it should be OK. Another item to address is adjustment of the pilot jets. The reason the bikes got their reputation for being "cold-blooded" is because they were set rather lean at the factory to meet EPA standards. The problem with that is that the bikes ran like crap and took a long time to warm up. By simply richening the pilot mixture a bit, it's a much friendlier bike.

Now, in stock form, if you pull the "choke" knob out and twist it a bit (usually to the right), it will lock in place. If yours does not do that, and especially if it's really hard to pull, splurge, get a new cable.

.

 

[Guest]

As mentioned by Steve, how much maintenance have you done with your new bike? have you checked the valve clearances? that type of cold starting issue can easily be from your vavles needing to be adjusted, then your carbs need to be synched of course and a simple adjustment to your fuel and air mixtures.

 

[JTGS850GL]

I know these machines are well known to take a long time to warm up...

Actually not that true. If the carbs are good/clean, ignition working (good points and condensers), timed correctly and the valves are set properly, then these bikes fire right up and go off choke in less then a minute. Over due maintenance is probably your issue. Here's a list of things to get you started:

Rebuild carbs COMPLETELY with new O-rings from head out. Look for any cracking on the intake boots and replace them if needed.

Adjust the valves. Verify that every valve is within spec.

Verify ignition timing. Check point gaps. Verify you have good spark on all cylinders. Spark needs to be bright and blue.

Replace plugs. Replace any cracked or damaged plug caps. I usually replace them all.

Make sure the air filter is clean and verify that everything is sealed up properly.

Clean and check all your connectors for any corrosion or damage.

Change all your fluids and filter. That includes your engine/transmission oil, secondary drive gear oil and final drive gear oil.

In the end you'll have a solid dependable machine that will fire right up and be off choke in 30 seconds.

As for the choke sliding down, pull back the rubber boot under the knob and turn the cap under it clockwise to tighten it. There are some cone shaped prongs that add drag to the metal choke shaft the knob is attached to. By turning the cap clockwise you're tightening down onto the cone and adding more drag.

 

[chuck hahn]

Cable on my Cooley is worn out and wont add anymore drag. What I do is full choke and then modulate it back to about 2000 Rs and just hold it a good minute till it warms up and idles well on its own. Then get mounted up and away we go.

 

[Sandy]

Cable on my Cooley is worn out and wont add anymore drag. What I do is full choke and then modulate it back to about 2000 Rs and just hold it a good minute till it warms up and idles well on its own. Then get mounted up and away we go.

Chuck. You need a "Super Duper VM Carb Choke Lever Wedgie". Seriously, get stick a little smaller diameter than a pencil about 3" long and cut to a taper for about an inch on one end. Pull the choke cable to set the choke and insert the stick under the choke lever on the #4 carb and slide it out to adjust idle speed and remove when ready to ride. Think of all those 2 minutes you can save. Discovered this handy trick when I had a broken choke cable during a trip ....worked great.

 

[chuck hahn]

The minute i spend holding up then knob doesnt bother me any. But it shouldnt tale more than a good minute or so for a bike to be off choke and idle while the guys getting ready. One of these days ( when the cable itself actually snaps ) I will get around to putting on a new one..HA HA

 

[tkent02]

I'd rather spend a minute or two replacing the choke cable, but that's just me.

 

[chuck hahn]

I dont have the money for a new cable...and its working good enough as is for now far as I am concerned.

 

[Guest]

Here in Canada we stick a Toonie under the choke nob, works like a charm.

 

[Rob S.]

I know these machines are well known to take a long time to warm up...

This is how mine works:

Starts instantly on full choke
Revs start to raise to 4k or so
Quickly back the choke off to let it idle about 2,500
Hop on and ride away (gently)
Turn choke off fully after I get in second gear

I try to ride gently for the first mile or so, even though it responds fully.

According to Cycle World in 1982, that's how it worked brand new.

Even though yours is a different model, I strongly suspect the procedure should be the same. I ride off shortly after starting to avoid disturbing the neighbors. If I lived very rural, I'd probably let it sit at 2k rpm for about a minute before departing.

 

[Frank Z.]

All part of the "charm" of these old GS's, nico. Get to know/accept your particular bike's warm-up characteristics... and, of course heed the word of forum maintenance.

Wanna get out of the garage faster? : fuel injection.

 

[nicogarceron]

Thank you guys for all the replies! great to feel I can count on this forum. I'm mechanically inclined, but this is a new beast for me so I have to catch up with it. I'm confident the PO did a lot of preventive maintenance, like new set of carbs (he gave me the old ones in case I need them), new front forks, all fluids were changed recently (I know I know, I'll change it myself again just in case).

I've ordered a new set of tires, they arrived today... and they have different threads... one is street and the rear one is dual sports. I've seen some cafe racers wearing these dual sports, and they look cool. My question is, can I use them anyway since their threads are different?? or should I go change them to have the same type?

Also, the PO gave me a Dyna electronic ignition, he said he never got the chance to install it... should I install it or not? (I've heard it make a difference).

Pictures coming tomorrow once I get the new registration!

 

[nicogarceron]

Ok, here is Suki

 

[nicogarceron]

I'm trying to upload more pics, but somehow the uploader gives me an error.
Anyway, the seat is not original, the PO made it to have a more comfortable ride (he likes to travel around with his wife on he back, cool dude). I will be changing it to something with a little more style. I work for a workout machine manufacturer so I have access to really nice foam and tools for that.

Also, I jumped onto the freeway last night. It was my first time and I knew it was gonna be empty. I got it to 60mph and didn't want to push it. Rides much better than I thought! Warming up is not bad, I have to use full choke at first and let it rev by itself kinda on the high side around 2,500rpm's, then start playing with the choke til it can idle without it... I hear a couple of backfires from time to time... but that goes away once I jump on it. takes around 2 mins to rev by itself and then its ready to go.

Also, any thoughts about the new tires? anyone can tell me the proper size for the front and rear on this 1979 gs850? I believe is 100/90-19 for the front and 120/90-17 for the back? if I'm right, there is not much out there for this size on the rear tire... but hope I'm wrong. I would love to go with a vintage look. Any thoughts?

Thanks!

 

[1074cm3]

Hey kids, see that thing on the side? It's called a kickstarter. The way things should be.

 

[tkent02]

I'm trying to upload more pics, but somehow the uploader gives me an error.
Anyway, the seat is not original, the PO made it to have a more comfortable ride (he likes to travel around with his wife on he back, cool dude). I will be changing it to something with a little more style. I work for a workout machine manufacturer so I have access to really nice foam and tools for that.

Also, I jumped onto the freeway last night. It was my first time and I knew it was gonna be empty. I got it to 60mph and didn't want to push it. Rides much better than I thought! Warming up is not bad, I have to use full choke at first and let it rev by itself kinda on the high side around 2,500rpm's, then start playing with the choke til it can idle without it... I hear a couple of backfires from time to time... but that goes away once I jump on it. takes around 2 mins to rev by itself and then its ready to go.

Also, any thoughts about the new tires? anyone can tell me the proper size for the front and rear on this 1979 gs850? I believe is 100/90-19 for the front and 120/90-17 for the back? if I'm right, there is not much out there for this size on the rear tire... but hope I'm wrong. I would love to go with a vintage look. Any thoughts?

Thanks!

In warm weather it shouldn't take much choke at all, the fact that it does indicates it is way too lean. This will burn things up inside. Valves maybe or hole a piston. For instance, I use about 1/3 choke, it fires immediately, within ten seconds or so it will run OK with no choke at all. This in warm summer weather. In cold weather it takes a little more, but wouldn't need full choke until it's far below freezing temperatures.
Having to use full choke in warm weather is bad. Fix your carburetors.

Tires, there is nothing that looks vintage that rides worth a damn. You can have any two, long life, traction and handling, or low cost. There are great cheap tires that don't last very long, great for handling that hold up a while but cost a lot, or cheepos that last forever but ride like crap the whole time. We have favorites for whatever you decide.
Also decide what you use it for, highways, windy canyon roads, some gravel roads, rain or dry, or whatever.

 

[nicogarceron]

In warm weather it shouldn't take much choke at all, the fact that it does indicates it is way too lean. This will burn things up inside. Valves maybe or hole a piston. For instance, I use about 1/3 choke, it fires immediately, within ten seconds or so it will run OK with no choke at all. This in warm summer weather. In cold weather it takes a little more, but wouldn't need full choke until it's far below freezing temperatures.
Having to use full choke in warm weather is bad. Fix your carburetors.

Tires, there is nothing that looks vintage that rides worth a damn. You can have any two, long life, traction and handling, or low cost. There are great cheap tires that don't last very long, great for handling that hold up a while but cost a lot, or cheepos that last forever but ride like crap the whole time. We have favorites for whatever you decide.
Also decide what you use it for, highways, windy canyon roads, some gravel roads, rain or dry, or whatever.

Thanks Tkent02. So what do you use? I've tried to find Dunlop k70, but they don't do it for my rear tire size . I feel my options are quite limited cause of my rear tire size... What's an affordable good option?
And also, where's a good resource of DIY for the GS's?

 

[tkent02]

Cheap and sticky, not last very long, Shinko Tour Master 230. Really sticky, higher price, Pirelli Sport Demons. Last longer, not quite as expensive, Avon RoadRider. Not RoadRunner, they suck. Hard slippery last a long time? I don't know, I don't go there.

What do you mean, good resource of DIY?

 

[Steve]

Change your rear tire to the proper size, your selection will improve drastically. 130/90-17 is what should be on there.

.