New to me 1982 GS750T

[Lloyd]

Update

Well the bike still bogs out to a stall if I'm not "revving the balls" out of it from a start. Mid and top end are pretty good. I set the float as close as I could, checked the coils and I believe they are both good. Any other suggestions?

[gearhead13]

Check voltage at the battery with the bike running. Compare voltage at the coils to battery voltage to see how voltage drop you have, maybe do the coil relay mod. Check plug cap resistance.
Fix your tach, maybe you just need a cable from a bike salvage yard.

[cloudbreakmd]

Welcome from another T owner.

[almarconi]

Float height should be checked but FUEL LEVEL is critical. I've found that even if all your floats measure the same height your fuel level could be off. It only takes a tiny amount of adjustment on the float tab to make your level too low (lean) or too high (rich). The fuel level effects all the jetting positions in the carbs.

[Lloyd]

Check voltage at the battery with the bike running. Compare voltage at the coils to battery voltage to see how voltage drop you have, maybe do the coil relay mod. Check plug cap resistance.
Fix your tach, maybe you just need a cable from a bike salvage yard.

Yes the tach cable is broken at the engine. I want to get it running properly before I dump anymore money into it.

Tomorrow I will check the voltage. How do I check the plug cap resistance, the plug wires do not come off the coil packs. Also what is the accepted voltage loss at the coils?

Thanks.

[Lloyd]

Float height should be checked but FUEL LEVEL is critical. I've found that even if all your floats measure the same height your fuel level could be off. It only takes a tiny amount of adjustment on the float tab to make your level too low (lean) or too high (rich). The fuel level effects all the jetting positions in the carbs.

Where can I acquire a fuel level gage? Is it possible to make one?

Thanks.

[gearhead13]

The plug caps unscrew from the wires. The other ends are glued into the coils. You need an ohmeter to check plug cap resistance.

[almarconi]

Where can I acquire a fuel level gage? Is it possible to make one?

They occasionally show up on ebay. The hard part is making the adapter for the fuel bowl. If you have a spare float bowl drain screw, you could drill a hole lengthwise through it and either tap for a fuel barb or epoxy in a piece of brass tubing. The other part of the gauge is either a piece of tubing or a syringe body with a tube on one end. On the BS32's the fuel screw is a 6mm x.75 pitch.

[Lloyd]

They occasionally show up on ebay. The hard part is making the adapter for the fuel bowl. If you have a spare float bowl drain screw, you could drill a hole lengthwise through it and either tap for a fuel barb or epoxy in a piece of brass tubing. The other part of the gauge is either a piece of tubing or a syringe body with a tube on one end. On the BS32's the fuel screw is a 6mm x.75 pitch.

It sounds like I can make one, do you have a picture of one? How is it used? Just hook it up to the fuel bowl and hold the tubing along the side of the bowl? Where should the fuel level be if that is the case?

[almarconi]

It sounds like I can make one, do you have a picture of one? How is it used? Just hook it up to the fuel bowl and hold the tubing along the side of the bowl? Where should the fuel level be if that is the case?

I have attached a picture of a fuel level gauge. The service manual will specify the correct level. You hook it up, put your tank on prime, the bowl will fill and the tube will fill. Let it stabilize, the fuel will seek a level in the tube equal to what is in the bowl. Line up the tube to the side of the bowl and measure the level. Some manual tell you to do it with the bike running on the center stand. This is a good way to check, but to adjust the float tabs, I find it easier with the carbs held in a vise and using a remote fuel tank.

[Lloyd]

I have attached a picture of a fuel level gauge. The service manual will specify the correct level. You hook it up, put your tank on prime, the bowl will fill and the tube will fill. Let it stabilize, the fuel will seek a level in the tube equal to what is in the bowl. Line up the tube to the side of the bowl and measure the level. Some manual tell you to do it with the bike running on the center stand. This is a good way to check, but to adjust the float tabs, I find it easier with the carbs held in a vise and using a remote fuel tank.

I can definitely make one of those. The only thing is I don't see the level in the service manual. Any Help out there?

[hmsa42]

Had a Similar Problem

I had a similar problem with my 750T this spring when I rebuilt it, my issue was when I replaced the vacuum line I made it a little long and it had slight kink in it. I'd get to about 6K RPM's and then she'd start to bog down, not sure if it's the same issue with yours or not, but it did affect fuel flow enough to oversaturate the mixture with air. If you need specs on some of the carb stuff, let me know since I have a manual to refer to and I rebuilt mine as well, so I had to go through it all.

[Lloyd]

Check voltage at the battery with the bike running. Compare voltage at the coils to battery voltage to see how voltage drop you have, maybe do the coil relay mod. Check plug cap resistance.
Fix your tach, maybe you just need a cable from a bike salvage yard.

OK, I checked the coils while the bike is running.

Voltage at the battery is 12.9
Voltage at the 1-4 coil is 6.4
Voltage at the 2-3 coil is 5.4

The method that I was checking the voltage was with my volt meter on the positive and negative terminals of the coil. I am assuming that this is the proper way. I also tried the positive terminal and using the mounting screw for the coil and got these results...

Voltage at the 1-4 coil is 11.8
Voltage at the 2-3 coil is 11.8

Is this bike a candidate for the coil relay mod?

[gearhead13]

Well you are down over a volt, so for the $5 for the relay and some wire and time you can be sure that this isnt contributing to your problem. I bought 2 relays and keep one on the bike in case one goes bad.

[Lloyd]

Well you are down over a volt, so for the $5 for the relay and some wire and time you can be sure that this isnt contributing to your problem. I bought 2 relays and keep one on the bike in case one goes bad.

Which method did you use?

http://www.posplayr.100megsfree3.com/FH012AA_Charging/DynaS_Coil_RelayMod.pdf

or

http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html