GT 380 Exhaust Internals

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arthur
Posts: 128
Joined: Wed Jun 17, 2020 8:55 pm

GT 380 Exhaust Internals

Post by arthur »

Hi has anybody ever taken apart the pipes on a 380 ?
I don't mean just taking out the baffle but actually cutting them apart?
The reason I ask is when I pulled the baffle to clean/repack I pushed a length of 10mm copper pipe inside to clear any crud but the pipe only goes about half way( probably only just past the length of the baffle) then hits something solid I would have thought the pipe would go all the way up to the header
So my question is are there extra internal baffles /bracing or is there a mummified mouse stuck in there?
Still trying to get her to run on all three
Good spark
got petrol
good compression
But left hand cylinder is struggling the header pipe is barely warm ,black crud is leaking out of the exhaust port and spattering out of the drain hole and the exhaust gases exiting the silencer has very little pressure ,
Makes me think the silencer is blocked
Any thoughts??
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: GT 380 Exhaust Internals

Post by barney01 »

To give you an idea whats inside. This is a photo from Baz of a 750 exhaust same sirt of internala.
Attachments
DSC_0253.JPG
NO SMOKE .......NO POKE
arthur
Posts: 128
Joined: Wed Jun 17, 2020 8:55 pm

Re: GT 380 Exhaust Internals

Post by arthur »

THANKS AGAIN Barney :D
Judging by that a length of pipe should pass through .
Maybe one of the strengthening rings has rotted and collapsed
I will try again and remove the right hand side baffle to compare it
GOOD THING IT RAINING TODAY
wardy
Posts: 1244
Joined: Tue Jul 13, 2010 5:36 pm
Location: north lincolnshire

Re: GT 380 Exhaust Internals

Post by wardy »

I had the same issues with my bike, on the same cylinder... turned out to be a blocked jet on the l/h carb, so I'd check this first... also, could you try firing it up without the exhaust on for a few seconds, just to see if it fires on that cylinder?
hell of a racket, but may be worth it!
cheers
Andy
Andy;
1976 gt750A; 86 FZ750
1977gt380A
1982 z400j
1981 z650f.....1988 Sufolk punch 14"
"look;it's my bike; when you own it ,you can paint it any colour you like!"
(I once painted my Z650 PINK and had the pink panther logo on the tailpiece)
arthur
Posts: 128
Joined: Wed Jun 17, 2020 8:55 pm

Re: GT 380 Exhaust Internals

Post by arthur »

Hello back again
So I pulled both outer exhaust baffles out and shoved a length of 10mm bar up them to check for blockage
The bar went all the way to the header on the right hand pipe,
but on the left it stuck around the indent for the stand a bit of wriggling and persuasion with a rubber mallet it went deeper at this point I removed the exhaust from the bike to get a better look and on tipping it up a couple of hundred ML of oily petrol sloshed onto the floor and my boots (carbs working then!)
a bit of pushing and pulling of the bar and tapping the outside of the pipe with the mallet dislodged a large chunk/ring of carbon from I think from the join between down pipe and silencer
It measured about 4 cm in diam with a center bore of 1 cm ish along with a few other bits of carbon and what looks like a piece of exhaust bandage or some other woven product around 3 cm in length and 1 cm wide :o
I can only assume someone in the past has tried to use it as a seal for the down pipe to barrel and it has broken off and lodged in the pipe.
I have put her back together and she is on three and sounds much better and even tries to idle although I think that the sodden oily wadding that passes as baffle wadding may need to go .
HAPPY DAYS


would post a pic or two but I don't have a hosting site any more
(photobucket?) :roll: If any one wants one PM me with e mail and I will forward one on
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: GT 380 Exhaust Internals

Post by barney01 »

Great news! Get rid of any wadding it will restrict exhaust gas emission unless its brand new. It will sound better too :D
NO SMOKE .......NO POKE
arthur
Posts: 128
Joined: Wed Jun 17, 2020 8:55 pm

Re: GT 380 Exhaust Internals

Post by arthur »

OK here we are again :D
I removed the old oil soaked wadding She's a bit loud though, I may need to break out the ear plugs
A bit flat in lower rev range but come 5 grand she picks her skirts up and flies although anything above 60 mph is INTERESTING and a bit wayward on the handling front .
I think I will stop tinkering for now and see how the summer goes
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: GT 380 Exhaust Internals

Post by barney01 »

You can buy the baffle wadding to quieten the exhaust note.
https://yambits.co.uk/exhaust-powervalv ... 3_930.html
NO SMOKE .......NO POKE
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