Motorcycle Repair: 1975 Suzuki T500 Carb/perfomnce prob., suzuki t500, jet sizes

Question
Hi Bill,  I had purchased the above bike for $500.  The bike is immaculate, the guy rode it till about 83 when he went blind in one eye and it sat in his garage since.  The carbs on inspection were siezed up and beyond rebuild.  I purchased two new Mikuni 32s from pro cycle.  The bike starts and idles great, and runs pretty well through the lower gears, but when I get in the top end and try to open the throttle up it bogs down.  I currently have it set and it idles at about 1000rpms.  I tried adjusting the air and fuel thinking that it may be too rich.  But it did not seem to help.  I am new to two strokes and just bought a whole new cable set for the bike thinking maybe it was a problem with the throttle cable.  Any ideas as to what Iam doing wrong? Many thanks!

Answer
Paul, I am not a Suzuki expert, but if you didn't put carburetors that were calibrated for that engine, you will have to find the correct settings to make it work. Assuming that it hasn't seized from being too lean at full throttle, you will have to experiment with the main jet sizes and see what it needs. You will need to learn how to read spark plugs and also how to test the engine safely w/o harming it or yourself.

Generally you want to go to a rich main jet size to where it is too rich and then jet down from there.

The mixture screws you are turning only affect the idle mixture and how it transitions to part throttle. You must change the main jets for 3/4 to full throttle settings.

Before you try to dial in the carburetion, be sure that the ignition timing is set properly. Set the carbs LAST after everything else is properly tuned.

There are lots of T500 websites out there. Browse Suzuki T500 and find some who can help you further.

Bill "MrHonda" Silver