Exhaust sizes for 75 GL1000. Adding new exhaust

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Cakey
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Exhaust sizes for 75 GL1000. Adding new exhaust

#1

Post by Cakey »

I am going to be taking off the original pipes and putting them in the shed for a rainy day. I have been reading the how toos on adding a Harley on triumph exhaust (great by the way) and then researched what I can get a hold of for reasonable price here. Second hand is non existent or wrong pipe.

So I think I have settled on these Dunstall Decibels. They are nice and long 28" which would leave about 7" or so if adaptor pipe I think. They suit To suit 1 5/8 inch (41mm) pipes but also come with reducer sleeves to fit 1 1/2 inch (38mm), 1 3/8 inch (35mm) and pipes.

So I was hoping someone can confirm the pipe size in mm or inches that I need to go to the stock 75 header pipe? I am getting a few conflicting sizes in my search. I would the need to work out which size pipe is available here and which end to use the adapters. From what I have read the header pipe should be 1 3/4" but I need to confirm.

When I measure around the pipe at the current header it reads 2" or 51mm so it's a bit conflicting with what I am researching.

Thanks
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#2

Post by Mrirbic71 »

I'm not sure on the 75' but on the 82 1100, the header connection as you have it Described is 1 3/4".
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#3

Post by Cakey »

Does anyone know if the GL1100 Manifold fits on the 1000? I believe the first couple of years of the 1000 the end of the headers were straight like mine but after that the had a bit of a bend up. This would make my install even easier if they did.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#4

Post by robin1731 »

Cakey wrote:Does anyone know if the GL1100 Manifold fits on the 1000? I believe the first couple of years of the 1000 the end of the headers were straight like mine but after that the had a bit of a bend up. This would make my install even easier if they did.
Yes the 1100 will fit the 1000.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#5

Post by Cakey »

Do you know if they have a bend upwards at the end Robin? or from which years the 1000 header changed to a bend upwards?
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#6

Post by robin1731 »

I think it changed in 78 but I can never remember which was first. Sorry. Someone should be here to soon that will know that answer.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#7

Post by Cakey »

The questions are getting crazier. I might have a chance of getting a pretty new Mac Slash cut exhaust at a really good price instead of going down the original road. Comes with headers and everything and would cost me about the same price or definatley cheaper if I had to buy second hand headers. Only stickler is that they were purchased for a GL1100 and not the GL1000. I know that the headers should mount straight up then but anyone know if the mounting points are different between the modles or possibly if it would fit with some minor adjustments.

Any info would be good. Thanks
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#8

Post by Cakey »

It's ok I just had to get them anyway before they were gone. They have only been on the bike for 7 hours and are near new. To get that here for $325 I am not going to get close to that anywhere else. And at least I will save my original headers and pipes now. I will make them fit if I have too.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#9

Post by robin1731 »

The difference with a "full" system for the 1100 is where the cross over piece is. I think they are far enough back to nearly hit the rear tire.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#10

Post by Cakey »

robin1731 wrote:The difference with a "full" system for the 1100 is where the cross over piece is. I think they are far enough back to nearly hit the rear tire.
I had read that somewhere and wasn't sure if it would be the same with aftermarket. I am sure that no doubt the centre stand could come into play somewhere too but I won't sac rice the centre stand so maybe my exhaust guy would bend me up a bit different shape maybe. I see that the brackets look like they have a fair bit of play as well.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#11

Post by Cakey »

Got the MAC 4 into 2 exhaust on today. The system for the 1100 isn't a straight swap over fit to the 1000 but at under half cost of a new one and postage I grabed it.

Headers fit straight on but the left side goes straight into the side stand bracket. So that got cut off. I don't use side stand anyway and couldn't come up with any other options.

I cut 25mm of the end of each side header outlet to bring the cross over back a bit from the wheel. Also had to make up a couple of 45 degree bend bracket hangers. Still have to go up to the hardware store and by another that's a bit longer because the right side is up a couple cm to high. Looks a fraction out of wack from behind.

I left the baffles in thanks heavens because it sounds just flat out mean when you give it a bit of twist. I'm over the moon.

It will be interesting to see if performance improves. I will give the carbs a balance soon.

Bike didn't het the tyre when I took off the centre stand and went a bit further away. Centre stand just touches the pipe so I have to do something about that. I know old fogey has mention before about a different year or style of bracket that has a more curved leg.

Did I mention it sounds awesome! devil1
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Before
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After
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Right side needs to come down a fraction
Right side needs to come down a fraction
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Cross over is close
Cross over is close
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Side stand bracket had to be cut off
Side stand bracket had to be cut off
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#12

Post by Gowing »

Wow, very impressive looking exhaust, to bad you had to loose your side stand, but
I think it looks great. I'd like to hear it.
Dave

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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#13

Post by Cakey »

Gowing wrote:Wow, very impressive looking exhaust, to bad you had to loose your side stand, but
I think it looks great. I'd like to hear it.
I will try and do a you tube link or something for you.

Thought this info might be helpful for anyone adding an aftermarket exhaust. I spent some time make some heavy duty plate still hangers today and got both pipes level.

I marked the spot on the side stand with some red tape to see where it was touch on the exhaust. I had been looking last night on the net to find a different shape leg but decided I would use blow torch, heat and bend. Then a real easy solution dawned on me. I made up another small plate bracket to go under the bolt head of the centre stand bracket. It comes out and stops the centre stand going all the way to the top of its travel. Problem solved. Doesn't rattle on the stand and I put some rubber heat shrink over the end of the bracket to stop it marking the paint. I havnt given up on the side stand either. I kept the bit that I cut off. It's basicall the metal around the bolt hole circle. I reckon I am going to be able to weld it onin slightly different angle and either use the same stand with a custom bend or a leg off another bike.

I should of expected it but I think I will need to rejet with the more open pipes. I'm a bit confused though because the bike had the puff of smoke on start up, not always but sometimes and today it billowed out. Looked like a bushfire.

It calmed down but I was wondering if it was carb related. I did a gauge synch and each carb bank was level just the sides had to be levelled back together.anyway problem for another day. Havnt had a chance to take it out yet but when I do I will pull the choke out a bit and see if it I oroves or not.
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Red tape where the leg was hitting the muffler
Red tape where the leg was hitting the muffler
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Little bracket under bolt head
Little bracket under bolt head
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Just enough clearance from the muffler.
Just enough clearance from the muffler.
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#14

Post by CYBORG »

seems like a very good solution. And one that might work for others
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Re: Exhaust sizes for 75 GL1000. Adding new exhaust

#15

Post by Cakey »

Just a bit of useless if information for those that like useless information like I do to file away one day.

I couldn't live with the tyre so close to the cross over pipe. I was riding the bike and cracking walnuts at the same time. I could not get that short piece of pipe bent with three bends to give me more clearance and the only other suggestion was two mandrel 45 degree bends and then weld in a 90 degree bend. Real headache but might be doable one day.

Anyway I did not want to cut off or weld the cross over joins in case I wanted to use them again. A mate suggested using a 35mm Welch plug over the end of the pipe and clamp it down. The pipe was 30 mm diameter and the internal of the Welch plug was 30mm. Clamped them down and they are not going anywhere. Really easy solution with no welding, now when I can run into someone who can make the crossover pipe for me one day I can just take them off.

Like I said. Useless I formation to file away.
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