'83 GS750ESD Party Popper!

[Anonymous]

I've got an 83 GS750 ESD and am having problems with a popping sound out of the exhaust. One day on the way home she just started to backfire and sputter with a good loss of power. I nursed her home and trouble shot the electrics (all good) cleaned the carbs, changed the plugs all with no change. She will start right up but has trouble idling and when I blip the throttle she backfires. Any tips? 8O

[Anonymous]

Sounds like you still have a fuel problem. What did you do to clean the carbs? What condition is your air filter? What is the condition of your fuel filter?

[Anonymous]

I took the carbs completely apart, used carb cleaner and then blew out all the jets, holes and what not with my compressor. the K&N air filter is clean and the glass fuel filter is clean too. I'm leaning towards a possible valve clearance as my problem and that's next.

[Anonymous]

How did this problem develop? Was it sudden onset or has it been running worse over time up until when it started to backfire? How did the plugs look when you pulled them. Why are you suspecting the valves? How about high tension electrical failure (plugwire arcing, coill, or ignition set failure)? Valves wouln't be where I would go next.

Blaine

[Anonymous]

Thanks Blaine, it just happened on the way home one day, no prior signs of any problems. I switched the coils and they test fine, the Black Box tests fine and so does the stator and signal sending unit. the Volt. Reg/Rec. and the Stator are ELECTREX products and they are fairly new units with less than 3000 miles on them. I was thinking valves as i've got 76,000 miles on the bike and it's the head I built the bike with. I've done routine valve adjustments and I'm thinking they might be getting tired.

[Billy Ricks]

If it's not carb problems you may have had a valve adjuster spin out. I missed a shift once and buried the tach needle. After that the bike sounded anemic and did some popping. I was afraid I had bent some valves. After pulling the valve cover I found two adjusters had spun completely out of their rocker arms.

[Anonymous]

Thanks Billy, I guess it's time to take the valve cover off and have a peek see. Just curious why 70% GS700 / 30% GSXR? Ken

[Billy Ricks]

Thanks Billy, I guess it's time to take the valve cover off and have a peek see. Just curious why 70% GS700 / 30% GSXR? Ken

Front suspension, wheels, brakes, Yosh Duplex exhaust, rearsets, and a couple other things are GSX-R parts. I was one of the first to do the suspension, wheels, and brakes on this site. In fact this site didn't exist back in the early 90's when I did the conversion. I also have an 1150 fairing I'll add later along with some Cosworth pistons. Took years to find rings for the pistons. I'd like to find rods and crank for a 750 first, but I am getting a little antsy to install them. I have some V&H cams to go with the pistons. But I also need to have my rocker arms welded up first.

[Anonymous]

Hey Billy, the Yosh Duplex has me wondering. Is that an unmodded fit onto the GS? I can't find any more aftermarket exh. for the GS's except for a V&H Megaphone. I've currently got the Yosh canister made for that model. If so what is the Model # of the Yosh pipe and is it still available? Also what year GSX-R did the front end come off of? Ken

[Billy Ricks]

I don't remember off hand what year the pipe was from. I know it was from an air/oil cooled model which means pre '93. It is the stainless model with exhaust spigots that uses springs to hold everything together. I picked mine up off of Ebay. The seller screwed up and spelled Yosh "Yoshimera" so not many people saw his auction. I think I paid $125 for the header and midpipe then picked up a Yosh RS-3 carbon canister for about another $125. It fits great as is except it is a tight squeeze up under the pan. I use one of those shields for soldering next to flammable surfaces to keep the heat off the pan. I actually needed the tight fit to give me a little more ground clearance.

My front end is the one used on '88-'90 models. You should stay away from the '88 though since it was the shortest and even the Gixxers had clearance problems with it. It has adjustments for everything. I drilled and tapped the top clamp to accept bar clamps and use a K&N superbike bar. Clipons would bang into the tank.

[oldschoolGS]

Wow, I'm impressed 76,000 miles! I thought my 45,000 was a lot. Currently my clutch basket is on the way out and will get beefed up this summer. Speaking of valve adjustments, just wondering if anyone else ever noticed in the factory service manual section 2, the photo and description is mislabeled. The No. 1 and 4 cylinders are mislabeled as the photo appears to be turned around. Real confusing as you have to look closely to notice and if you follow instructions to the letter you swap the C and D settings. I have a very old, about 1985, manual so it could have been changed in later publication. Any how, good to see someone else appreciate a great bike. Ed- Custom 83 GS750ED

[Dink]

Have you considered the condition of your muffler? It may have collapsed a baffle! Does it sound any different? I s the entire exhaust tight? try putting a rag over the end of the muffler to block off the flow and see if it blows out anywhere else!
Dink

[Don Lobacz]

A compression test may save you from digging into the motor. If they are good and consistent then the valves have to be opening OK. It sounds like it may possibly be an air intake leak or a slightly plugged pilot circuit.

[Anonymous]

just curious, but my 1150 always has popped a little upon decelerating. I always thought it was kind of cool, makes the pedestrians watch out when i go around a corner. I always thought it was caused by the jetting being a little too lean. is this not the case? I seem to have plenty of power (but i couldn't say no to more hp's). I've not had any problems with overheating or anything. So is something else causing it besides my jetting and or my loud V&H exhaust?

Mookie