Can Anyone Help With a 1983 GS450A Suzukimatic?

[gsJack]

Those bikes were choked down by cam and carb changes to maxamize mid range performance but yours is running out of breath even sooner than it should, could it be something as simple as a very dirty air cleaner element or a stuck choke?

[noiseguy]

OK, carbs were cleaned at 2200 miles, and it has 3500 now?

If you haven't been through the carbs yourself, you can't be assured that they were done, or done right. The fact that your top speed's increasing the more you ride makes me think you're cleaning the carb as you're riding. If you don't want to tear down, run a tank or two with Sea Foam and see if that helps.

Compression. Check it. Valves. Check your clearances. You should be doing this on any new-to-you bike (the compression, esp., before you buy it.)

Interesting that your top speed picked up after changing the oil. I wonder if the crankcase was filled with automotive oil with friction modifiers that messed with the bike's clutch. I don't know how these "automatics" work... car auto transmissions are full of clutch packs that do the decoupling. Running a couple of crankcases worth of "real" MC oil may help if this is the case.

[comradeiggy]

To be honest, friction modifiers shouldn't do anything to the top speed. If it's not the carbs, then one thing I can think of is that the lock up clutch in the torque converter isn't working, but I don't know if the bike even has a lock up clutch to begin with.

[wyobuck]

Thanks for all the responses. Removed air filter and found it to be pretty clean, so cleaning it did nothing. I am running Bell's Marine MXO as I do with all my bikes every third tank. Found to be the best by a bunch of VMax owners here in FL. Think ACE Hardware carries it. One half ounce to 5 gallons. As I said in the beginning bought this for my girlfriend to learn on and the lack of top speed is not a big issue now. Will run it for a few months before I get real serious about finding the problem, maybe take it to a shop. Just thought someone here had firsthand experience with this bike.