72 Suzuki GT380

15V is too high, IMO, although there are a lot of bikes out there charging at that voltage. A flooded cell battery will tolerate it fairly well if you keep it watered.

The only things that need to be done on the bike are:
1) front brake
2) idle properly

Is the proper procedure to adjust carbs to idle properly to let the machine warm up, unplug 2 of the wires and adjust for one still plugged in? Then do the same thing for the other two? I have it adjusted as it says in the book, but it starts to get up to about 3500 RPMs when warmed up, and won't come down.

I've never heard of a procedure to run a multi-cylinder engine on one cylinder at a time to tune carbs. It wouldn't work, because you would have to increase the idle speed for the only functioning cylinder just to keep it running.

The carbs have to be balanced. That requires a manometer to do properly. I built one myself for under $20, but the kind with vacuum gauges on it is easier to use.



After the carbs are balanced, you need to adjust the idle air mixture screws. Do one carb at a time with it idling at the desired speed. Each screw is adjusted for fastest idle. A lot of bikes have a cover over the idle mixture screw, so you often have to drill a hole in that cover, then drive a screw into the hole and pull the cover out to expose the screw. No need to replace the cover. It is there from the factory for EPA compliance reasons.

Thanks ADC. I think I can manage making something like that. I've attached some photos because I don't have any ports to tie into except for the center carb which has the port for the vacuum operated shut off valve. So I drilled and installed an extra nipple into a spare carb I had to see if it would work. It fits in there snug and I feel I can cap that off somehow so it's always there and I can use it again. Have you done this before or do you think it would work?

No, you have to synchronize the carbs you are going to run.

There is usually a screw in each intake port for this purpose. I looked for instructions on this, and it looks like there was no vacuum port for carb synchonization until 1974.

http://www.ozebook.com/compendium/techbuls/SerBulletin%20GT%20022-26.pdf

ADC,
Your funny The spare carb was just a trial run to see if it fit before doing it on the real deal. So I guess what your saying is that that won't work.
Yep, no intake port that I saw. So now what? I've synced the little detents on the slides as best I can.

Probably would work to add vacuum ports to the other two carbs. Not sure how you are supposed to sync them without vacuum. I suppose interrupting spark to each cylinder and shooting for the same RPM drop with each one would work reasonably well.

actually got them syncd as best I could. its not too bad. revs on demand and idles at 1200rpms. I think a video is in order... tomorrow.

Took the bike out for it's maiden voyage this morning. Damn this thing is FAST! I love it.
But still no brakes, so that was scary

I didn't like how the bars felt, they were just a little too narrow and they were pitted from all the rust that was on them (not stock bars). So I actually had another set of stock bars (go figure) and made some pro taper looking bars out of them. Just cut off about 1.5 inches' of the rise and then pulled them back about 2 inches. I cut a bolt and stuck it in the bar for the plugs and then welded them back together. I'm really happy with it but I know it will rust sooner or later, so I'm thinking about painting them black, or trying to find some black heat shrink that will fit the bar and use that. Don't know yet. Pics to come

Here's what I took off in the rise:


And here it is on the bike:

The only thing I've done since my last post it put a tube in the rear tire, and order some small parts.
I think my rear hub diameter is almost at it's max diameter. Unfortunately, the other one I have is past it's max diameter, too. Bummer.
Now my clutch is getting caught up and I can't find where it's coming from. It's hard to pull the handle in and when you get to the end, it kind of feels like it travels past the 'catch' and let's go. I thought it was the perch, but I switched with another and it does the same thing. The cable is new and moves freely when not hooked up. I know that doesn't mean it's not the problem, just wanted to throw that out there. I'm a little reluctant to take the clutch cover off and check the clutch since the points are connected to that also. (I have no idea what I'm doing.) Does anybody know if I can just take the clutch cover off and leave the points attached to cover? I know there is a plastic gear somewhere in there and I don't want to screw it up. Thanks in advance
Anyways, have been riding it very gently over the past few days, and there are a few issues to iron out, but nothing real big. Starts on 1st kick after sitting over night, so i think thats good. Battery charges and all lights work. Almost there ;D

Possible that the drums are worn out but more likely that you just need new brake shoes.

Clutch issue is most likely adjustment. Sounds like it reaches teh end of its travel/lift. Try adjusting it at the motor first and then the cable

Thanks Teazer. I noticed the max number when I changed tube. Measured with a scale and thought measurement was close. New shoes ordered. Don't think I set up cable wrong. Set at engine side first tthen at handle. did it a couple times to make sure, got same results. I'll disect more tomorrow. Just was wondering if I could safely take clutch cover off while leaving points intact to look at clutch

Doubt it's the clutch itself, but more likely the lift mechanism on the engine side cover

http://www.suzuki2strokes.com/forum/viewtopic.php?p=111154

http://www.powersportsplus.com/parts/search/Suzuki/motorcycle/1972/GT380/CLUTCH/parts.html

Look at the snail cam that lifts it and the screw adjuster in the middle of that set up.

Yep, I printed that off Bike Bandit, too. Funny thing is, mine doesn't look like that. i have a gear that is swirled. It has the screw in the middle of it that makes contact with the push rod and then a locking nut. Maybe I should take a picture or video because my complete lack of knowledge of technical termonology is showing itself :

Edit: Ok, it might look like that, but I don't have it here so I can't look at it. Will post something tomorrow. Thanks for your help.

I took the cover off that holds the lift mechanism and now see that the drawing is correct, I was wrong :. It works properly and is fully greased. I then took the end off the lever and pulled up on the mechanism with the cable and it moves freely. It appears that my cable is the problem. Sucks because it is brand new New one ordered. I am glad that it wasn't the clutch.
I just want to add that I tried moving cable in different routing positions to no avail. I also tried another handle bar with perch and lever attached and got the same thing.

Why oh why would they make a stock speedo cable 2 ft too long? Why can't it just come from the speedo mechanism to the gauge and have just a little slack. Fuck@!!! Has anybody shortened this cable before? 1 step forward, 2 steps back- I swear!!!!!

Should be perfect. Sure it's not a tacho cable or from a different bike?

It says on the invoice GT380 GT500 GT750 GT185 Speedo Cable

It screws in fine just about 14" too long. I've contacted the seller to see what we can do. Thanks.