Old Two Stroke With Blocked Exhaust Pipe

by George
(Middletown, NY. USA)

So I have a 1964 Suzuki K11, a small 80cc 4 speed 2 stroke enduro. It used to go 60mph no problem, now it feels like it only uses half the throttle.


After you go past halfway it doesn't accelerate more it just stays at the same speed and gets a deeper tone in the exhaust. Feels as if running out of gas but there is plenty. If you shift gears (e.g 2nd to 3rd) the problem is gone until you try to go past half throttle again.

The exhaust I think is clogged as I can barely feel any air coming out at any throttle speed/position. Would this be the sole problem with the bike? Someone said it might be.

I asked the bike shop and they said to torch it. I told them it was old and was chrome and they said they'd never seen a 2 stroke with a chrome exhaust and couldn't help me :(

I don't want to burn the chrome off my bike. It's not in the best shape, but it's nice looking. Definitely not at the point where a charred exhaust is better looking than what I have. However if that's the only way? I guess I could go flat black with it. But I'd rather keep it chrome.

Someone said oven cleaner?? How would I do that? Wouldn't the left over residue catch on fire after I put it back on the bike? Or destroy the inside?

I have a low 1650 psi electric power washer sprayer, one friend said to just spray that in there and that should clean it out a bit.

What should I do? I want to ride again, faster than 35-40 mph.

Thanks for your time.

- It could be a number of things that is causing this to happen. Personally, I would be pulling the carburettor to pieces and making sure it's clean and in good working condition. It sounds to me that it has a problem reaching the higher revs which is most likely to do with the carby.

Try repacking the muffler - maybe it's blown out and some of the packing is caught up inside blocking the exhaust. Otherwise, remove the pipe and clean it out. There are a few methods - oven cleaner is one of them. Use boiling hot water to rinse it out with afterwards and you won't have to worry about any unwanted flames ;) Some people reckon boiling hot water, rinsed around (and even shake up some small stones inside) a few times is enough to break down carbon build up.

Sometimes this mechanical game is simply a process of elimination.. And sometimes it's just easier to take it to the mechanics!

Let us know how it works out!

Hayden -

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