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Since I'm moving to AZ, and will be forced to run a box muffler for the first time ever, I need help. Which Mac muffler sticks out the least from the exhaust flange of the engine? I'm HOPING there'll be enough room between the flange and the chain to fit a muffler into. There's not a lot of room to rotate the motor on the side plate to clear the chain before the air stack hits the seat back. If anybody has the dimensions, I'd appreciate it. Thanks! Ted

Hi Ted,

The Gem G1273 box muffler seems to take up the least room from my experience. I'm not sure about the Reed version. I'll take some measurements tomorrow, and post it here.

BTW, It was great seeing you, Charlie, and everyone else at TBO. We're already planning for next year!


John

Thanks, John. It was good to see you, too! What a great bunch of guys and gals there were at Fremont.
I know it's silly to have to ask such rudimentary questions as about the mufflers, but I hate the things, and I've never owned any McCulloch box mufflers. We quit karting about the time mufflers became mandatory, and I didn't get back in until pipes were the thing. On the Bandit, the top chain strand runs right across the exhaust ports. The Max Torque I'm running now has a little more clearance to the engine than the Rev Grip, but I'll bet it isn't enough! I'll probably have to water jet a new engine mount side plate so the engine is rotated upwards to clear the chain. Can't do that until I get settled in Arizona, as all my CAD files from Sandia are on a CD, and it's packed away! TJ

It looks like 2 9/16" from the engine exhaust flange to the outside face of the muffler, and 3 7/8" across the top of the muffler. There certainly may be others that will be less, such as the Reed version for Macs. But the Gems are the only box mufflers that I have.


Hope this helps,
John

Hi Ted,
I am using the old style Reed 2 pc mufflers on 2 of my karts.
The muffler is about the thinest one I know but I don't think it will clear your chain. Right now the muffler measures 2 7/16 from the exhaust flange to the widest surface that your chain will run across. The muffler could be machined for more clearance but I don't know how that would effect performance. Maybe you could space the engine a bit between the mounting bosses and mount plate to get clearance instead of creating another mount.

I like these mufflers and they actually seem to improve performance for some reason but they are also pretty loud because the exit directly out the back. Attached are some pics of an inboard and outboard Rev Grip with these mufflers.

Good luck,
Scott

Thanks, John and Scott. Looks like things will be close! Rough measurement gives me about 2-1/2" face to chain, allowing about 1/8" clearance. The early Reed might do, especially if I machine a small amount from the mount flange and maybe even the outside face. Worth a try, anyhow. I'd like to leave the engine where it is, both for appearance and for the ease of routing the throttle cable. Since Vince offers the thin style, I'll give him a holler. Thank you to both of you! Ted