I was able to break the 8mm chain before the tool broke. Then I ordered this $10 chain breaker last night:
Last year, I bought a used pipe like this for $16, minus muffler and brackets:
It's for a Tanaka engine mounted on a 4-wheeled powerkart, so it's wide. The head pipe leaves horizontically from the exhaust port. I am unable to mount the pipe on my bike, in any of the engine's four possible positions.
Right now, I adapted a Happy Time expansion chamber from SBP onto my Tanaka engine. The pipe's round flange is grossly mismatched with the engine's large rectangular port. I'm amazed that a LOT of extra power was made over the Tanaka's stock muffler.
There is a loss of 52%!!! in port area, using the Happy Time head pipe instead of the Tanaka head pipe. I also used this SBP pipe on my GP460 engine. The exhaust port and head pipe was also mismatched, but not as bad as the Tanaka 47R's port.
A LOT of power should be realized, simply by using the correct sized head pipe!
The correct head pipe could probably be fabbed for a price. However, I haven't had second looks from the police, so I'll chance using a pipe specifically made for the Tanaka 47R.
It took a LONG time (one year) before I convinced myself to buy this second pipe today:
BladeZ Performance Pack by Tanaka - 47cc
I have never seen anyone use Tanaka 47cc engines on motorized bicycles. I'm taking a big risk. The pipe is guaranteed to fit the 47R on a Tanaka scooter. However, no one can guarantee if this pipe will fit on a motorized bike.
Oh well, all my 2-stroke engines can be mounted in four different positions with the Scooter guy center frame mount. Here's hoping I don't need to eliminate the 4-liter Happy Time fuel tank to use this pipe.
The air cleaner and venturi stack in this kit is for the Tanaka 47 engine. My 47R already has a high-performance carb and filter.
This is touted to be the best pipe for Tanaka 47 engines.
However, it's also rated to be a very loud pipe.
An adaptor is included to mate the original muffler with the muffler in this kit. Hopefully, this should silence the loud pipe. I also have the SBP muffler to experiment with.
Unlike the $16 expansion chamber, this head pipe leaves the exhaust port vertically, If this pipe won't fit, hopefully its head pipe will mate with the $16 pipe to work on my bike.