New guy/ Gs400 won't run

[Kingbesus]

Hi guys,
New guy here and I bought a gs400 a few weeks ago for $25. The bike is in decent shape. I replaced the points and a bad coil and now the bike starts for a few seconds and then dies. I looked around and couldn't find anything related to my issue. Just wondering what else I could check?

Also, where do the 4 vacuum lines off the carbs attach to? They are just hanging there blocked off.

[tom203]

Hi guys,
New guy here and I bought a gs400 a few weeks ago for $25. The bike is in decent shape. I replaced the points and a bad coil and now the bike starts for a few seconds and then dies. I looked around and couldn't find anything related to my issue. Just wondering what else I could check?

Also, where do the 4 vacuum lines off the carbs attach to? They are just hanging there blocked off.

$25 and you expect it to run? Plenty of info on here about this issue- most likely carbs that have sat with old gas for eternity waiting for you to clean them and move on to other problems. Easiest thing to do is follow link to Basscliff's site- lots of priceless info to absorb.
Unlikely to have 4 vacuum lines, but you should have one plus some vent /drain lines

[Kingbesus]

Thanks, I assumed some of the lines off the carbs were vent tubes but all 4 of them were closed off and my repair book doesn't mention anything about them. Why shouldn't I expect it to run for $25? It has compression, spark and fuel. I forgot to mention that I already cleaned the carbs.

[tom203]

Thanks, I assumed some of the lines off the carbs were vent tubes but all 4 of them were closed off and my repair book doesn't mention anything about them. Why shouldn't I expect it to run for $25? It has compression, spark and fuel. I forgot to mention that I already cleaned the carbs.

Well, you're right basically, but being able to run WELL is the real trick. Just how did you clean these carbs? strip and soak ? The suggestion to Basscliff's site was to discover what you need to know- you can take shortcuts and get lucky or you can become very adapt at carb removal and frustration. Put model/year of your bike in your signature- this helps others when you ask questions. Also mileage, any history that you know is helpful.

[koolaid_kid]

So, this is a 4 cylinder bike?
We need a bit more info: year and model of bike.
Some do have vacuum lines for synching the carbs, and should be blocked off.
Some have breather lines which should be open. A pic or two would not hurt.

[Kingbesus]

I'll try to snap some pixs next time I go and work on it. The bike is a 77'. I don't know too much about the bike besides it ran 2 summers ago. The wiring harness was pretty messed up, so that was the first thing I addressed. The bike is in pretty decent shape otherwise. As far as the carbs, I tore them apart and let them soak for a while. I only bought this bike to kinda gain some knowledge on motorcycles. This bike will only pass the time until I can find a bike I really want.

[Suzuki mad]

What you describing in the first post sounds like a carb issue. You may have late the carbs 'soak for a while' but sat for 2 years with fuel inside isn't the best thing for them.

As for the 4 vents being blocked off and the bike being a GS400 from 77 its likely to be a twin than a 4 cylinder so something sounds wrong there.

[koolaid_kid]

Yes, it will be a 4 valve twin with dual carbs. Something is amiss in Denmark.
Post some pics, please.

[tom203]

I'll try to snap some pixs next time I go and work on it. The bike is a 77'. I don't know too much about the bike besides it ran 2 summers ago. The wiring harness was pretty messed up, so that was the first thing I addressed. The bike is in pretty decent shape otherwise. As far as the carbs, I tore them apart and let them soak for a while. I only bought this bike to kinda gain some knowledge on motorcycles. This bike will only pass the time until I can find a bike I really want.

You will learn lots! see attached pic- looks like this model has extra drain lines , carb overflow probably. Also that site Alpha-Sports has good diagrams. These carbs are tricky to clean and ethanol fuel is nasty stuff if it sits.

[koolaid_kid]

Do you think the 77 had CV carbs? My 78 XS650E did, btw, so they were around. I miss that bike, great around town.

[tom203]

Do you think the 77 had CV carbs? My 78 XS650E did, btw, so they were around. I miss that bike, great around town.

Beats me- never seen one, but that's what The Alpha diagram said. Maybe Mikuni needed a guinea pig to try out their cv style and Suzuki voluteered ,to atone for their years of two stroke smoke.

[koolaid_kid]

Beats me- never seen one, but that's what The Alpha diagram said. Maybe Mikuni needed a guinea pig to try out their cv style and Suzuki voluteered ,to atone for their years of two stroke smoke.

Atone? Did you ever own one? They were the most reliable of all the two strokes; I owned 3 of them. Great bikes, and if someone was tailgaiting you then you just let them lose you in the cloud of blue smoke.
I enjoyed all my 2 strokes, the 4 strokes never had a chance in a race. Hondas were a joke back then. Heavy, slow, and difficult to work on b/c they had all these chains and valves and lifters and all this unnecessary junk.

Rather than hijacking this thread, I will respond about the Bighorn here. It was a joke when it came out, big, heavy, and with an adjustable front axle that never performed up to its potential. Kaws were also known as the least reliable of the Japanese two strokes.
I had an XL175 and was the first bike I really started to take off road. Slow but not heavy it was an ideal bike to learn how to off-road with.
Hijack over.

[tom203]

Yeah, yeah, I hear this from lots of two stroke fanatics. I had Kawasaki 350 Bighorn- rotary valve wonder and super at fouling plugs. Still got a 74 honda xl350, only dirt bike I road that loved beach sand- would go on any surface and get 40/50 mpg doing it,plus no smoke. Now if only my leg was still strong enough to start it!

[Kingbesus]

Thanks for the help. I guess I'll tear apart the carbs again and do a more thorough job cleaning them. Does anyone have any experience or advice on switching from points to an electronic ignition? I finally have the points adjusted but I would like it to be slightly more reliable.