Dunstall Replicas - 1971 OIF T120R

[NM Bonny]

I'm still waiting on parts for the side stand repair per the main thread, but repacked the mufflers--which took about 30 minutes. Very nice aspect of these replicas is the baffles slide right out so you don't have to R&R the mufflers to serve them.

As you can see, utterly useless, wispy packing comes inside. I got the super duper (supposedly) expanding stuff from the UK, and didn't use all of it because you're quite limited in how much you can wrap the core by the hole in the end of the can. Image no. 3 shows what was left over.

Moreover, due to the taper you cannot cover the first few inches, and must next put an abbreviated wrap around the next few inches. The balance is right about 1.5 times around the core if pulled tightly.

The sound is a little quieter, or perhaps slightly more mellow... I can't tell which until I fix the manifold air leak and get the bike to settle down into an idle. After that and the side stand are done, I'll post a video with some varying rpms and load and we'll see how she sounds!

 

[sikatri]

Nice! What’s the wire you used? Anything special, stainless steel?

 

[NM Bonny]

Nice! What’s the wire you used? Anything special, stainless steel?

I'm sorry that I didn't see this. I don't know why I didn't see a notification (operator error, I'm sure!).

No.. darn it! I should've used some stainless safety wire for affixing bolts I have... good idea. Just good old mechanic's wire I had lying around.

Here's a link to how these sound--and my apologies for this project taking soooo long to get running.

Idle and a few throttle blips.

So, bottom line? These aftermarket Dunstall replicas are not too loud, after all--with the upgraded packing, that is. In fact, the sound from the saddle is really nice. And the performance--together with the Mikuni carbs I added--is excellent.

I'll be adding a GoPro video to the main restoration/mods thread next weekend, so you'll be able to hear them from my perspective riding the bike.

 

[NM Bonny]

Okay, here is a video (there are two parts for some reason I don't understand) so you can hear the Dunstall replicas with Acousta Fil packing from the UK. Microphone is attached to my back, so it's not actually this loud of a bark from inside your helmet... but it sounds pretty sexy!

BTW the tach seems fairly accurate, but the speedo needs calibration and is wildly optimistic right now...

1971 Bonneville T120R OIF cafe racer POV

1971 Bonneville T120R OIF custom cafe racer POV - Part 2

 

[Bloodknot]

Okay, here is a video (there are two parts for some reason I don't understand) so you can hear the Dunstall replicas with Acousta Fil packing from the UK. Microphone is attached to my back, so it's not actually this loud of a bark from inside your helmet... but it sounds pretty sexy!

BTW the tach seems fairly accurate, but the speedo needs calibration and is wildly optimistic right now...

1971 Bonneville T120R OIF cafe racer POV

1971 Bonneville T120R OIF custom cafe racer POV - Part 2

Very nice sound. What’s it like on the overrun? The originals had this delightful twitter on a closed throttle.

 

[NM Bonny]

Very nice sound. What’s it like on the overrun? The originals had this delightful twitter on a closed throttle.

Yeah, that's a good description of the overrun--not at all obnoxious but a definite sound...

Ah, actually there is one place where I snap it closed. Part 2, start watching at 1:30 as I take the main left-hander. At 2:04 I let off fairly quickly, and you can hear the overrun at least once. It's in top gear so not as pronounced as in 2nd or 3rd--and it's not wrung out that far. But it'll give you an idea...

Overall I am very happy with them--and really like the removable/repackable baffle feature. I guess I won't be messing with them after all. The bike really scoots.

Today I was working to get more familiar with the bike's handling characteristics, so I can start pushing it through the twisties a bit. I went through that left-hander you see in Part 2 about 8~10 mph faster than in the clip, and it felt fine. The pavement is uneven in two ways--ripples plus some dips--and it doesn't have a very good bank to it, so it's a bit challenging. You might have noticed the little 'helmet on a cross' monument to the kid who lost his life in that curve not terribly long ago...

Anyway, one of these mornings after the commuter rush hour, I will strap the GoPro onto the guard rail at the apex and do a few runs so I can see what I'm doing. I feel like that'll be more useful than a low-side, bike-mounted setup...?