1992 Columbia par car muffler blocked

[Littleg15uk]

I have a partially blocked muffler on a 2 stroke. Tried the fill with diesel and let it roast in a fire. That helped a bit but not enough to stop too much pressure into it so it leaks from the joints and causes too much back pressure to the engine. Any other ways to clear it? The muffler is no longer available so I wondered if anyone had found an alternative replacement.

[Lochlin]

These mufflers can be tough but there are some options.

Tearing the one you have apart, cleaning it out, and putting it back together. This has been done before and there a couple of prior posts about it. There is some fiberglass in those mufflers that gets gummed up over time and needs replaced. Unfortunately, that involved cutting the muffler open and welding it back up when done.

Like you mentioned, OEM mufflers are tough to find. Pretty much any muffler from any 2 stroke will work as most run in the 90 to 130 psi compression range (I installed a Yamaha G1 muffler on a Columbia). That said it's a much more difficult process than you might think. If I recall, early HD mufflers are still available and I would think that they may be easier than a G1.

1) You have to cut your the muffler tube that attaches to your motor.
2) You have to cut the G1 (or equivalent) muffler where it would attached to the motor.
3) You have to get a flexible exhaust tube / adapters from an auto parts store and put new muffler on the cart. From your motor, the logic is:

Motor to old muffler piece to adapter to flex pipe to adapter to new muffler

4) Mount it up real good.

[raydhd]

I used the up to 1981 HD muffler on my Columbia. As mentioned you just need to cut and adapt the head pipe and some slight redrilling of the mounts along with a reducer on the inlet of the muffler to match the header pipe. The same muffler is now on my 440 cc sled engine. I still have the modded head pipe, flange and brand new exhaust donut for the columbia that I never installed due to engine swap. There is a pic on page 1 of my 1982 harley thread of what the finished product looked like. Page 3 of my sled engine build shows the muffler swapped onto it.