New to me 1982 GS750T

[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

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

 

[Lloyd]

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

I think im going to go with this method:
http://members.dslextreme.com/users/storagecliff/images/ignition_coil_ relay_part2.pdf

 

[gearhead13]

I have Dyna coils on mine, so I have heavy gauge wire from bat to relay then to the coils, mounted my relay under the left side cover on the same bolt that holds the solenoid. Never has my relay died on me, although I do carry a spare. I left the wires from the ignition box alone and just spliced wire to them to make it to the relay.

 

[Lloyd]

OK, well I did the relay mod and it is still the same, but the spark is great! I'm going to attempt to make a fuel lever gauge and see where I am with that.

I have the the following again to just make sure everything is correct. Benched synced the carbs, purchased and used a colortune kit to adjust the fuel screws and then synced the carbs.

The bike still runs and idles great. It still falls on its face with a quick blip, but once you get past that it is very fast. In neutral on my bike lift, at prob around 2-3k rpms is where it is not running correctly. It is running rough and popping. What now?

Also, when rebuilding the carbs I did not change the O rings on the T's in between the carbs. No fuel is leaking from them, but could this be the problem?

I am really out of ideas, I need help!!!

Thanks guys

 

[Lloyd]

OK, well I did the relay mod and it is still the same, but the spark is great! I'm going to attempt to make a fuel lever gauge and see where I am with that.

I have the the following again to just make sure everything is correct. Benched synced the carbs, purchased and used a colortune kit to adjust the fuel screws and then synced the carbs.

The bike still runs and idles great. It still falls on its face with a quick blip, but once you get past that it is very fast. In neutral on my bike lift, at prob around 2-3k rpms is where it is not running correctly. It is running rough and popping. What now?

Also, when rebuilding the carbs I did not change the O rings on the T's in between the carbs. No fuel is leaking from them, but could this be the problem?

I am really out of ideas, I need help!!!

Thanks guys

Bump
Bump
Bump

 

[gearhead13]

So, you didnt fully disasemble the carbs? Sounds like a plugged pilot jet/ airscrew. Or maladjusted airscrew.

 

[almarconi]

Did you check the fuel level yet?

 

[Lloyd]

So, you didnt fully disasemble the carbs? Sounds like a plugged pilot jet/ airscrew. Or maladjusted airscrew.

Carbs have been torn down many times and thoroughly cleaned. All jets and the needle valve have been replaced. The only parts that were not replaced were the O rings on the fuel tee's because the rebuild kits did not supply them.

 

[Lloyd]

Did you check the fuel level yet?

Not yet I'm still looking for a bowl drain bolt that I can drill out. My local hardware store didn't have the proper thread pitch in that size bolt. Oddly enough they had the right nut for the bolt... I might buy a piece of brass rod and machine it to work...


To me it still sounds fuel related...

 

[Larry D]

The best way to tune your bike is by riding it, not on a bike stand. IMHO.

Let's say you're in second gear going around a 90 degree turn. What happens when you roll on the throttle ? Does it hesitate or stutter ? If so, you're a little rich on your pilot. Turn the idle air screws in a quarter turn and go try again. If you have to keep turning them in the idle is going to increase, adjust with the master idle knob. Kinda like the hightest rpm method, only by riding.

Are you certain you have the correct jets ? 42.5 for the pilots ?

 

[gearhead13]

So, were any of the old o-rings replaced? Im not sure of what kind of carb kit you had, but there are several o-rings besides the fuel links between the carbs. There is one on the fuel inlet seat and one on the idle mixture screw that should be replaced.