Total Motorcycle Community Forums

I have a 1980 Suzuki GS 450L. I am the second owner of this bike, as the first owner is a co worker that I have worked with for 35 years, and I remember when he bought it new, and rode it to work. It has 6700 miles on it, and I have had the carbs cleaned, new plugs, and air cleaner. The most I can get out of it is about 55 MPH. The book says it should easily do 70 or more, but I sure can't get it even to 60. It does have a windshield on it, but would that put up that much resistance to lower the MPH? I have done the speed sign thing, and the speedometer is right on. I use non oxy gas in it, so I won't have a problem with the ethanol. My mechanic that did the 2 carb cleanings told me to go with that instead of the ethanol. Everything is stock. I have not changed the sprockets, but that was an option left open to me. I live in MN, so altitude is not a problem. It starts right up, but is a little cold blooded for about 5 minutes. Any thing else I can look at to get this up to speed? my brother in law has a suzuki 400, and that will run by mine. Thanks

Richard

Hello and welcome to the forum.

Have you checked the compression yet?

I'd check the valves, just follow the manual.

You should see a max of 90 MPH out of it. You are right 55mph max is too low and there is something in wrong. I would try the simplest things first. It IS a 32 year old motorcycle so don't expect it to be 100% of new, it's an antique!

The "L" is the "cruiser" version of the GS, I wouldn't be surprised it if was geared lower than the "E" "ES" sport versions, thus a lower top speed. I would ditch the windshield and give it a try, it is good for - 5 to -10 MPH of your top. As JohnJ metioned, you should check the compression and pull the plugs and see if any of them are running lean (white)/rich (black). It's possible you might also have a cracked carb boot (how is the rubber on those?)

Mike

Thanks for the ideas. No, I have not checked the compression, and I did buy 3 ranges of plugs today, since I have not had time to pull them to see what they look like. I will be looking for a bigger bike anyway, but this bike is just a sweety to ride. My son has that Suzuki 650 naked bike, but I am not sure exactly what it is. It reminds me of my 1972 Kawasaki 750 triple that I had so many years ago. Trying to ride my sons bike is not much fun for me. My feet are to big, and by the time I get them on the footpegs, I am already putting on the back brake. I guess they are made for the younger set. LOL. Thanks again for the tips.

Richard