Author Topic: DS Pattern silencer  (Read 445 times)

Offline Matt_Harrington

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DS Pattern silencer
« on: June 12, 2022, 05:56:07 PM »
Hi, Is it possible to fit the silencer to a 400/4 with the down pipes installed or is it best to work from the silencer back to the cyl head?
I ask as I'm struggling to get the silencer 'aperture' (where the captive nuts are) over the frame loop. I have managed to sort the packing sleeve out on the silencer but I'm struggling to get the unit into position with the down pipes on the bike.
Matt
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CB400F 1976 - New project
Moto Guzzi T4 - 1981
Triumph 3T - 1946 - Now finished(ish)
Triumph 3T - 1947 (somewhat dismantled!)

Offline Nurse Julie

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Re: DS Pattern silencer
« Reply #1 on: June 12, 2022, 06:36:13 PM »
Hi, Is it possible to fit the silencer to a 400/4 with the down pipes installed or is it best to work from the silencer back to the cyl head?
I ask as I'm struggling to get the silencer 'aperture' (where the captive nuts are) over the frame loop. I have managed to sort the packing sleeve out on the silencer but I'm struggling to get the unit into position with the down pipes on the bike.
Matt
Yes, you can fit the downpipes and then the silencer. But, whichever way you go about it, only do any nuts / bolts up finger tight to start with. You need a huge amount of wiggle room on the headers to be able to line everything up so it fits. Are you sure you are trying to fit the silencer bracket to the frame bracket correctly and is it the correct bracket?
Im a Nurse, trust me, this won't hurt.....much !!!

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Online smoothoperator

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Re: DS Pattern silencer
« Reply #2 on: June 12, 2022, 08:23:07 PM »
I have just recently fitted a DS (Brituro) silencer. I don't understand what you mean by frame loop or captive nuts, that said. here is how I fitted mine. Down pipes and collector bolts fitted first. Gasket where silencer fits to the collector box was too large in diameter so I used 180 grit to reduce it down from memory 38mm to 37mm, or thereabouts. Slightly splayed out the silencer where it has the 2 slots then twisted back and forth onto the collector box. Then connected the silencer bracket, 2 bolts on the silencer and 2 bolts onto the frame. Finally tightened the clip on the silencer/collector box junction. I had previously read threads where others had to reduce the outer diameter of the silencer gasket.
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline Matt_Harrington

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Re: DS Pattern silencer
« Reply #3 on: June 13, 2022, 08:34:57 AM »
Hi, Is it possible to fit the silencer to a 400/4 with the down pipes installed or is it best to work from the silencer back to the cyl head?
I ask as I'm struggling to get the silencer 'aperture' (where the captive nuts are) over the frame loop. I have managed to sort the packing sleeve out on the silencer but I'm struggling to get the unit into position with the down pipes on the bike.
Matt
Yes, you can fit the downpipes and then the silencer. But, whichever way you go about it, only do any nuts / bolts up finger tight to start with. You need a huge amount of wiggle room on the headers to be able to line everything up so it fits. Are you sure you are trying to fit the silencer bracket to the frame bracket correctly and is it the correct bracket?

Mmm, The loop on my frame does not have the ability to have a separate bracket like the photo showing it. My frame loop has a welded on bracket as per the other photo.
So, have my frame been messed about with? Or is this a change in the frame somewhere along the lines. Interestingly I can't find the separate bracket in my parts book.
(Excuse the block of wood - it was to keep the centre stand away from the job in hand.
Matt

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___________________________________
CB400F 1976 - New project
Moto Guzzi T4 - 1981
Triumph 3T - 1946 - Now finished(ish)
Triumph 3T - 1947 (somewhat dismantled!)

Offline TrickyMicky

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Re: DS Pattern silencer
« Reply #4 on: June 13, 2022, 08:49:47 AM »
Your frame is the one with the pillion pegs on the swinging arm, the other, later, one has the pegs on the frame. Same exhaust, just the silencer is rotated to a different position. By a sheer fluke, I am still running with an OE system, but even with wonderful Honda technology, I found the only way too fit the system was to loosely bolt everything together, giving lots of wiggle room. Give yourself plenty of time, keep the coffee pot handy alongside the latest dictionary of foul language. It WILL fit, eventually, and it's a very satisfying feeling. Be luck,  Mike.

Offline Matt_Harrington

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Re: DS Pattern silencer
« Reply #5 on: June 13, 2022, 09:44:26 AM »
Ah Ha! That would explain it, Mike. As you say, I think I will loosen everything else off and take a steady approach. I have already 'turned' down the graphite seal. (which, BTW, seems to have a core of steel wool or similar) and that bit fits OK now.  Off to find that dictionary.....  ;)
Matt
___________________________________
CB400F 1976 - New project
Moto Guzzi T4 - 1981
Triumph 3T - 1946 - Now finished(ish)
Triumph 3T - 1947 (somewhat dismantled!)

Offline Matt_Harrington

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Re: DS Pattern silencer
« Reply #6 on: June 15, 2022, 03:54:06 PM »
Loosening off all the joints and headers worked a treat and exhaust is now fitted.  ;D

Out of interest, how far away should the foot brake arm/lever be away from the collector box? Initially it was fouling the exhaust but I slackened it all off again and now have about 5mm.

Soon be ready to fire up the ol' girl and see what else is wrong !!  ???
___________________________________
CB400F 1976 - New project
Moto Guzzi T4 - 1981
Triumph 3T - 1946 - Now finished(ish)
Triumph 3T - 1947 (somewhat dismantled!)

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1
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Re: DS Pattern silencer
« Reply #7 on: June 15, 2022, 04:21:57 PM »
I will try and find a photo showing the clearance. But, if its too close, your foot may foul on the collector box when braking. Personally, I don't have that problem with my size 4½ feet 😊😊😊😊
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Matt_Harrington

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Re: DS Pattern silencer
« Reply #8 on: June 15, 2022, 05:53:33 PM »
Thanks. When clamping it all down it closed up a little but seems OK - I'll wait until a test run...
Next job - air box removal!!!  ::)
Matt
___________________________________
CB400F 1976 - New project
Moto Guzzi T4 - 1981
Triumph 3T - 1946 - Now finished(ish)
Triumph 3T - 1947 (somewhat dismantled!)

 

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