1982 GS300L Not Running Well

[LAB3]

Cipher I got them back in ok, it was directly under the choke bar. I’m on to adjusting the idle. Life would easier if I didn’t have to take the tank on and off. With the vacuum system on these carbs do you need to plug the smaller fuel hose to run off a bottle of gas?

If the "Prime" function on the petcock is in working order it lets the fuel through without the need for vacuum. If you take the tank completely off you'll want to plug the vacuum lines to avoid trying to tune with a nasty vacuum leak (damn near impossible)

[Fritzey21]

Thanks LAB3 I got it the external tank to work. I think the new diaphragms stopped the racing up and dow but still wont’t idle without the choke. I pulled each plug wire separately and cyl 2 wont run on its own, so I’m now focused on that wire, connection or both. I found another thread from a similarly frustrated gs300 owner with good tips. The best stating check the wire resistance, should be 10 ohms.

[Mr.Vroom]

Thanks LAB3 I got it the external tank to work. I think the new diaphragms stopped the racing up and dow but still wont’t idle without the choke. I pulled each plug wire separately and cyl 2 wont run on its own, so I’m now focused on that wire, connection or both. I found another thread from a similarly frustrated gs300 owner with good tips. The best stating check the wire resistance, should be 10 ohms.

I have been down the very same rabbit hole as you with my Gs250. If you are going to replace the ignition system, there is a video of a guy replacing his 450's ignition with a dynatek system. I did it to my 250. Its a great video. But before you do that check the intake boots, where the carburetors meet the engine. if they are cracked out, YOU NEED TO REPLACE THEM! Extra air gets into the engine, and it throws off your air fuel mixture. Cruzin' image just started suppling them. (I'm actually going to buy some for my 250 today).

Link to ignition video: https://www.youtube.com/watch?v=hTJQzBMd5GQ&t=833s

[Fritzey21]

I ordered a petcock just to eliminate that issue. My valves are noisy so I was going to check them again while waiting for parts delivery. I looked everywhere to figure out the markings and owners Macaulay to figure out top dead center to adjust the values clearance. I settled on using a screwdriver in the spark plug hole. I checked them 2-3 times before putting everything back together and now wondering if that’s what caused the racket. Does anyone have a hint about how to find TDC on the GS300? Thanks

[LAB3]

I ordered a petcock just to eliminate that issue. My valves are noisy so I was going to check them again while waiting for parts delivery. I looked everywhere to figure out the markings and owners Macaulay to figure out top dead center to adjust the values clearance. I settled on using a screwdriver in the spark plug hole. I checked them 2-3 times before putting everything back together and now wondering if that’s what caused the racket. Does anyone have a hint about how to find TDC on the GS300? Thanks

Do you have manual? You're not looking for TDC you're looking for when the cam lobe is in the proper position. On my GS450 the cam lobe needs to be set parallel to the top of the cylinder head to measure, on the bigger bikes the lobe points away from the shim pad. Like I said, get a manual to make sure you got that right.

[rphillips]

It's obvious, what he said ^^^^, you need a manual. not being negative but there are even pictures in them that shows you how to find TDC.

[Fritzey21]

When I first read this I'm thinking, what kind of idiot works on a bike without a manual? Since LAB3 mentioned it's in the manual, I visited the garage this morning and again couldn't find anything about TDC. Then I checked the cover which says, GS300L Supplemental, and in fine print used with the Suzuki GT250T manual. So this makes me a slighly different kind of overconfident idiot. Holy S%$# all this time I was only working with partial guidance. So not a negative or crazy question and thanks for LAB3 and rphillips for raising it. The manual over on BikeCliff is over 300 pages, jeeess. My life is about to change, you guys are awesome thanks!

[LAB3]

I'm not the kind of guy that follows instructions either hence my need to carry a cordless drill and easy outs. Dunno, it takes up less room than a torque wrench I guess....

[rphillips]

300 pages??? Got to be several questions answered in them pages.

[Fritzey21]

Yeah the 300 pages includes the 250 manual and 300 supplemental. I’ll be printing that first section tomorrow at the office. My petcock was delivered today so I quickly installed and nothing new, still wont idle and wont run on right cylinder by itself. So I’m back to looking at that carbs, took them off again and review all steps in the tutorial.

[Mr.Vroom]

Yeah the 300 pages includes the 250 manual and 300 supplemental. I’ll be printing that first section tomorrow at the office. My petcock was delivered today so I quickly installed and nothing new, still wont idle and wont run on right cylinder by itself. So I’m back to looking at that carbs, took them off again and review all steps in the tutorial.

I had the same exact problem as you with my 250. It took me 4 years, but this last weekend I got it running like it should. The carbs are important. Use only mikuni or OE jets and needles. I replaced the diaphragms with some from Ebay. They seem to be of high quality. When installing the slides, make sure you get the diaphragms seated properly. And get new insulators for between the carbs and the cylinder head. I didn't think it would help any, but it did. Also, check to see if your ignition system is up to par and that the spark plugs are lighting.

[Fritzey21]

Thanks Mr. Vroom, I hear you on the intakes pipes. I swapped out the rings and added Alan hex head screws to get leverage. I’m pretty convinced it the float on the right side. I’m just waiting on new screws or take the old and drill them out for tubes as shown in tutorial. I’ll check the spark again to be sure.

[Mr.Vroom]

Thanks Mr. Vroom, I hear you on the intakes pipes. I swapped out the rings and added Alan hex head screws to get leverage. I’m pretty convinced it the float on the right side. I’m just waiting on new screws or take the old and drill them out for tubes as shown in tutorial. I’ll check the spark again to be sure.

I'll be interested to see how it works out for you. They are pretty fast and snappy bikes when working properly!

[Fritzey21]

Well I got everything set up to test the float levels over the weekend, found they needed some adjustments and did that dance 3-4 times. I didn’t detect the left side being crazy out of spec, but purchased a new petcock and installed new fuels lines with solid clamps to eliminate any air leaks. And for fun got a new air filter. I got everything back together and bike started right up. Then I noticed a gas leak which was my doing, because I forced one of the old screws in during the test and looks like stripped the thread on one float bowl. So I have to fix that and see if I can get it idle. It might actually be ready for a test drive before it snows.

[Fritzey21]

Fixed up bowl threads, added new gaskets but still runs rough and won't idle off choke. So now I'm down to seek professional help or part this out and move on.