Suzuki 2 Strokes

Well I will try to explain it

When driving a medium rpm or a constant rpm, the engine seam to make a rattle or chatter noise. Its irratic seams to come and go.

Could be comming from the pistons. the bike isen't running lean that I am aware of, I think it makes a ping noise when lean.
Could it be to Rich or a baffle?

This is not very specific explanation but its all I got.
Just wondering if its something I should worry about.

Bike is a 74 GT550 has 15800 miles.

Has there been any work done to the bike lately? Is the rattle a constant heavy metallic sound or just an annoying buzz? Does it matter if the bike is hot or cold? Always at the same RPM? At that RPM, does the rattle come and go in a cycle, such as there for ten seconds and then gone for ten, or is it there one day and not the next?
Check that all the bolts/screws on the engine are tight. Check all the covers to see if they are loose at all. Tap them with the handle end of a screw driver and see if they rattle/vibrate. Check the crossover tubes in the exhaust, they should be tight. Check the exhaust pipes and baffles. Check the chain guard and rear fender. And as silly as this sounds, check your tool kit. It should be be wrapped up tight.
Hope this helps!
Cliff.

As Cliff indicates, it could be a lot of things, and checking for loose stuff first is definitely smart.

Assuming everything is tight and that this problem just started and that prior to that it was running fine, then they are known for having the occasional starter clutch problem. My '74 looked like this on the left - the one on the right is what its supposed to look like.



I'd suggest first draining the oil and checking for any bits - if that seems OK, and if it was previously running well and this problem just started then I'd be looking at the ignition first (especially if you are running points), and then mixture.

Its all speculative till you do some searching around and as noted it could be anything...Also something to look at would be the plastic timing gear in the engine.

If I'm not mistaken, only the 380 has the plastic timing gear. Does your
side stand have the rubber stopper on it? Or the center stand for that matter.
As mentioned, a likely place to search is the exhaust system for loose balancing pipes, or baffles. Hopefully it is a loose screw holding something
inconsequential. Good luck, and happy motoring. Cheers.
Fred

It becomes more frequent in warm weather or when the egine gets to temp.

If I pull the clutch in it stops right away.

I will check over every part this weekend and report back on what I find.

Ok thats good news as it may isolate the problem,, it stops when you pull in the clutch??? well then id suggest you have a look at the clutch, its inner basket nut and the plates.

If I pull the clutch in it stops right away.

That sounds like a loose clutch hub nut.

That sounds like a loose clutch hub nut.

Or the starter clutch problem that Ian mentioned. Whichever it is it needs to looked at NOW.....not later. It will NOT get better on its own and, if not fixed, will make a heck of a mess.....never mind the whole safety issue.