Triangle Muffler Opinions

[onthegas]

On 11/14/2019 at 3:46 PM, vintagenut said:

Hey - when you get to the point of repacking your mid box, please post some pics and info on your effort, will you?  I'm very interested in seeing your approach to a re-packable mid box.  I don't know how quickly muffler packing degrades but I'd imagine after a couple seasons of regular riding, another re-pack would do the bike wonders.  Having it set up for easy access would be fantastic.  Hope to see!

Cheers -

 

 

 

 

Sorry for the late response. Other projects came first.
 

I removed the mid box to repair a small hole in the rear section. While it was off I got a good look inside. All the packing was long gone. I cut open the mid box about 3/4” of an inch after the taper in the front and removed the perforated core. Then I cleaned the carbon from the core and the inside. Using 22-gauge steel, I cut a strip 1.5” wide and put it around the inside of the mid box then brazed it to the rear section leaving about 3/4” sticking out to slip inside the front section. I drilled four 3/16” holes through the front section and inner strip. Next I wrapped the core with exhaust packing and put it back inside the rear section, slipped the front section over the strip using high-temp silicone sealant and fastened it back together with four pop rivets. It made a huge difference in the exhaust note. Now I can hear all the rattles in the engine.
 

As far as any impact on performance it’s difficult for me to judge that. I also installed an electronic ignition so the bike performs a lot better all around. At my last trial the bike never stalled and I only had two 5’s all day. 

Overall I’m quite satisfied with the performance. If I rode it more than two or three times a year I might actually be competitive in the intermediate class.

 

[feetupfun]

Neat job. Well done. The 250s are not as sensitive to the condition of the first muffler as the 325s are for smooth running.

Yes they are a mechanically noisy motor. I didn't realise quite how mechanically noisy until I watched a video clip of mine and a friend's Bultacos. Probably made worse using my phone to make the video. The late model motors are quite quiet for some reason, maybe the different finning on the head and cylinder and they also usually have fin rubbers.

[onthegas]

11 hours ago, feetupfun said:

Neat job. Well done. The 250s are not as sensitive to the condition of the first muffler as the 325s are for smooth running.

Yes they are a mechanically noisy motor. I didn't realise quite how mechanically noisy until I watched a video clip of mine and a friend's Bultacos. Probably made worse using my phone to make the video. The late model motors are quite quiet for some reason, maybe the different finning on the head and cylinder and they also usually have fin rubbers.

Thanks, I wanted to be able to fully remove the core to clean it, pack it properly and be able to clean and re-pack it in the future.

The motor is definitely noisier than my old M206 Pursang, but at least the exhaust note is more acceptable for some of the places we ride.

[onthegas]

On Monday I went back to a practice spot I hadn’t ridden at since before repacking the mid-box. This place has several long, steep hills with switchbacks. Normally I’d have to wrap out the engine just to make it to the top, but now the bike kept pulling with very little throttle. I was very surprised. It seems a properly packed mid-box does provide some low-end power to the 250.

Now I’m going to build some sort of a skid plate that will protect both the clutch and flywheel covers from damage.