First motorcycle gs400

[Guest]

Hey guys I'm so happy to be apart of these forums so that I can meet people and get a little bit of help and information with my new bike. I purchased a day ago a 1978 GS400. And it's not stock....I know I know. It's got pod filters on it, and straight piped fiberglass wrapped exhaust. I like the idea of a tinkering project and for 1900 bucks something that was garage kept and not ridden too often seemed like a good catch. I purchased this bike from a shop in washougal. They had finished minor things like fabricating a battery mount, regular maintenance, and carb cleaning. There's a few things I want to do to the bike. And that won't be a problem being that I am a volvo mechanic out here in Portland oregon. So maybe I'll meet some of you sometime and go ride. I appreciate this group all ready because although I know cars, bikes are a bit of a different ballpark. So a new chapter of my mechanicalobssessions begin.
For whatever reason I can't post a picture. I will make more attempts soon to show you guys this little cafe bike.

[dorkburger]

Welcome,
Interested to see some side shots in the daylight.
I like the two tone headlight bucket / ring treatment .

[pete]

Welcome! The little GS twins are fun bikes for sure, and as long as it gives you plenty of enjoyment it really doesn't matter how stock it is or not.

[Ziggy400gs]

Welcome,
Interested to see some side shots in the daylight.
I like the two tone headlight bucket / ring treatment .

I will take some more photos today and post them here? Or on the photo thread? Not sure which one would be best.

[LAB3]

Welcome! My stock 450 has been a lot of fun, usually I rehab a bike and ride it for a season and pass it along but I'm keeping this one. As to pictures, you can post them here keeping in mind you can only post one at a time unless you use a hosting service such as imgur or photobucket.

[Ziggy400gs]

20190414_164306.jpg

Here's one side shot

[Ziggy400gs]

20190414_164346.jpg

Taking forever to upload from phone. Here's another

[Ziggy400gs]

Engine does not match vin on frame. Looks like it's been rebuilt. But when I get on it in a lower gear it spotters. The pods on the carbs and straight pipe exhaust worries me. If I'm in right the right gear though and upkeep it in mid rpms, I can gas it and it runs okay. Any thoughts?

[Rob S.]

The carb jetting might need to be fine-tuned.

[pete]

Lugging it at lower RPM won't do too much with a smaller capacity twin. Not sure on the 400's but I know with my 450 anything below 5 to 5.5K RPM doesn't do anything spectacular. Nothing wrong with that, just not the most powerful point in the RPM range, and she definitely wakes up above that.

Having said that, I'd do a +1 on Rob's comment that it's definitely worth verifying the carbs have been tuned to the pipe and pods. If they've used cheapy pods, it's also possible there's a rubber flange inside that is partially covering the low speed inlet holes. I had that issue at one point myself but a set of velocity stacks sorted that out

[Nessism]

It should carburate cleanly through the range. Your jetting is messed up. And before jacking around with that too much be sure to add some baffles inside the mufflers because not only will that help, it will keep you from making all your neighbors hate you.

[Ziggy400gs]

Just figured I'd let you all know. I messed with idle mix screws, turned the left cyl out half a turn more than the right. Flat spot is hardly noticeable. And I'm replacing both plug wires as the boot just comes off one of them super easy so I taped it together in the meantime. Now there's virtually no flat spot. Still going to play with the needles see if I can make it happier but high rpm jetting seems fine.

[pete]

Let's see how far down a rabbit hole we can send you here

If you have to have the mixture screws at different settings, your carbs need balancing.

Great move replacing the plug caps too, they will definitely cause you grief if they're not right.

[Ziggy400gs]

Let's see how far down a rabbit hole we can send you here

If you have to have the mixture screws at different settings, your carbs need balancing.

Great move replacing the plug caps too, they will definitely cause you grief if they're not right.

SO I have a set of decent vacuum gauges and will balance the carbs when I pull the tank. But I'm going to replace plug wires as well being as the boot is falling a part on the cylinder that I have the idle mix screw leaner than the other. So I don't want to mess with jetting until I fix that ignition issue being that that cylinder is blacker inside and blows black smoke in the morning. So I have a feeling that the plug wire might be giving me issues even though I can't see it grounding else where. But I know to replace the simple things before I dive deeper. But still want to check jetting, mess with needle height, and balance the carbs so I know how to do this and can apply to future bikes I own. THANK YOU ALL FOR MAKING ME THINK AND GIVING ME DECENT REPLIES. I will start a thread with some pictures of adjusting needles, and jets and what results I get

[pete]

Good stuff, and probably a smart move! Definitely a good idea to fix the obvious issues first, then go from there.