Author Topic: Mac exhaust  (Read 2461 times)

artbone

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Mac exhaust
« on: February 14, 2012, 11:12:59 AM »
I'm sure this has been covered (time and time again) but I'm ordering a Mac exhaust for my old IOM bike (now Atl. bike) and I would like to hear comments from others who have used these pipes. Also, what else do I need when I take these off? Any gaskets, clamps, bolts that tend to break off after 30 years of use, spacers, etc. that aren't supplied with the pipes?

I'd like to hear other's experiences before I start the project so I can gather everything I need beforehand.
art
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
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Lucky

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Re: Mac exhaust
« Reply #1 on: February 14, 2012, 12:12:27 PM »
Start the headpipe bolts straight. Macs leave no room for error, & some have had to adjust the mounting flanges slightly.  replace all the gaskets now.  coat every bolt in anti-sieze, replace the chrome thick rings if there is any sign of flame cutting & be sure the Y pipe (which will get reused) is in good shape.  retighten everything after the first ride & probably a few rides afterwards.
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Rick G

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Re: Mac exhaust
« Reply #2 on: February 14, 2012, 03:28:16 PM »
I've had mine on for a long time , but it seems like  they gave a bit more mid range. There a bit louder , but then the stockers sound like ( wait for it!) a Hoover with a head cold) I removed the rear wheel , to install them. This gave much improved  access and visibility.
« Last Edit: March 27, 2012, 03:45:08 PM by Rick G »
Rick G
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'90 Suzuki VX800, 1990 Suzuki DR350.
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Tiger

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Re: Mac exhaust
« Reply #3 on: February 14, 2012, 03:42:00 PM »
 :) I've done a few of these and they are, for the most part, a pretty easy fit.

I would buy:
1 x set (4) of exhaust manifold gaskets.
8 x M6x1.0 x 25mm Soc' head cap screws.
2 x M6x1.0 x 45mm Soc' head cap screws
Anti-seize

Strip out all of the old exhaust unit...

The front exhaust gaskets are there for you to see, once you have removed the front pipes of your old exhaust. (They go between the front pipe flange and the cylinder head). You need to remove these and clean the area of old gasket material, etc. The rear ones are a PITA!!!...as you have to remove the two chrome manifolds that the 'Y' pipe goes in to...This is made easier by removing the battery/battery box & the TCI/over flow bottle....unless you have reeeeeeal tiny hands!!! Again, remove the two gaskets and any gunk. To hold the new gaskets in place I use a smear of red RTV on each one. 

I never reuse old nuts/bolts/washers, etc, as the local OnROV will tell you!! I use S.S. replacements and anti-seize. I think the four front and four rear manifold screws are M6 x 25mm Soc' head cap screws and the two exhaust clamps are M6 x 40/45mm Soc' head cap screws. ( 1.0 coarse pitch)

To install, start at the front and work back. (A jack will help hold the rear pipe/'Y' pipe in place). Put it all together 'not quite finger tight'...this will allow you to adjust as you go. Once you are happy with it, start at the front and nip it all up...and again... from the front back, tighten everything up tight...Start her up and check for any leaks...VOILA!!!

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artbone

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Re: Mac exhaust
« Reply #4 on: February 15, 2012, 11:01:14 AM »
Thanks guys. This will make the job go much easier I'm sure.
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
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artbone

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Re: Mac exhaust
« Reply #5 on: February 16, 2012, 09:02:00 AM »
The IOM bike is an '82 with the flapper valve airbox. It's always had the "Vision Stumble" but I've always just lived with it. I've never rejetted the carbs at all.

Will I need to rejet with the Mac pipes or will that make the mixture leaner and the stumble worse? And if I need to rejet, which jets, (there's what, 4 different jets you can change?) what sizes, etc? I should mention that I'm using a non stock aircleaner. It's some sort of foam but the base looks like the stock one. I don't know if it leans out the engine or not.
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'06 Suzuki VStrom Running

Lucky

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Re: Mac exhaust
« Reply #6 on: February 16, 2012, 10:34:40 AM »
nope, no rejetting required. 
for the stumble, double check your synq, pilot settings & you can also slightly adjust the nounting on the flapper door (the holes are slotted)
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Kiwi

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Re: Mac exhaust
« Reply #7 on: February 16, 2012, 10:40:06 AM »
I cant speak to the MACS, but removing my exhaust was rather tricky.  It had most likely had been on the bike since new and the bolts were seized up.
I got them off with a lot of Pblaster ( a penetrating lube ) and an impact wrench.
The hex bolts had stripped out.  So i took the impact hammer, and a Torx bit and used that to get them out.
US 82 XZ550 with the flapper Airbox

artbone

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Re: Mac exhaust
« Reply #8 on: February 18, 2012, 08:00:17 AM »
nope, no rejetting required. 
for the stumble, double check your synq, pilot settings & you can also slightly adjust the nounting on the flapper door (the holes are slotted)
What am I supposed to adjust about the flapper door? Just make sure it's all the way closed, or is there a way to change when it opens. I always assumed it opened when the manifold pressure dropped (when the carb butterflys open.) Is that true or not?
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'06 Suzuki VStrom Running

Re-Vision

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Re: Mac exhaust
« Reply #9 on: February 18, 2012, 09:35:49 AM »
You can have some effect on the flapper door by moving the vacuum actuator and linkage, the ones that I have all appear to be adjusted to where the flapper door just touches the rubber stop with no vacuum applied. Rubber stop keeps flapper from total closure by 3 mm.          BDC

QBS

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Re: Mac exhaust
« Reply #10 on: February 18, 2012, 11:14:58 AM »
The door is vacume operated.

Night Vision

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Re: Mac exhaust
« Reply #11 on: February 18, 2012, 04:01:04 PM »
you can adjust a non vaccum flapper by adding weight to it... adding two nickles will slow it's opening
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Cdnlouie

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Re: Mac exhaust
« Reply #12 on: March 03, 2012, 11:39:00 AM »
Artbone here is just a suggestion to check sometime.  You might try two revolutions (complete turns on the threads) on your accelerator pump rod (shortening the rod and advancing the spray initialization) just to see if it helps with the hesitation.  If no change then just put it back. Ideally you should just clear the throttle plate on actuation, but I had a set of carbs in which the rod was too long and changing the rod length in small amounts then road testing, actually cured the problem.

You can pop out the rod end and do it on the bike by holding the threaded portion with pliers and rotating the male end by hand.  Ideally it should have some thread locking compound on it afterwards just to make sure it does not move.

The MACs don't require any changes to tuning. Personally I added a custom made baffle pack to mine to cut down on noise, but keep the pure sound prominent.  I reduced the output opening to 3/4 inch, rather than the 1 inch stock.  I found a bit more back pressure greatly improves gas mileage and mid-range.

artbone

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Re: Mac exhaust
« Reply #13 on: March 26, 2012, 08:14:17 PM »
The bike is at my friend's house in GA and I came up to work on it last weekend. When I arrived he had pulled the old pipes off but hadn't opened any boxes to see if the new pipes had arrived. Sure enough, no pipes. I called Mac and the pipes are backordered. PITA.

Anyone have a set of Macs they want to sell?

Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
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artbone

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Re: Mac exhaust
« Reply #14 on: March 27, 2012, 02:58:06 PM »
I've just spent 2 days working on the IOM Vision. My buddy David pulled the exhaust off before I got there so, with no pipes, I figured I would work on the stuff I had in hand and let David put the new pipes on when they arrived. I pulled the starter and replace the seal and brush plate, cleaned everything up and put it back together. It was much easier without the ex pipes in the way and up on a lift table.

Then I pulled the gas tank and refilled with new fuel, drained the float bowls, and made sure the petcock was working. Next I pulled the front brake apart and cleaned the grung off the piston, put a little new brake fluid in the bore and pressed the piston back in, drained the master cylinder, and bled the system. It works fine now, instead of the front brake dragging.

Then we pulled the right sidecover and replaced the clutch with a complete Barnett unit, springs, steel plates, friction plates, and all. Easy peasy except getting the chrome water lines apart. After that, it as no problem.

Then I put the petcock on prime a few minutes, put the choke on, and fired her up. It cranked and ran in about 10 seconds. With no pipes it sounded pretty wild. I let it run about 2 minutes and shut it down. No oil or water leaks so I'm pleased.

So, 2 days, about 12 hours for 2 guys and I'm about ready to ride. David is going to put the pipes on and install a fuel filter and I'm going to come over a day early before Barbers and ride this beast to find the bugs. I'm excited.
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'06 Suzuki VStrom Running

artbone

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Re: Mac exhaust
« Reply #15 on: March 29, 2012, 07:42:22 AM »
Old Bike Barn has the pipes listed but I ordered them and they don't have them in stock so I canceled the order. I'm sure they just drop ship them from Mac.
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'06 Suzuki VStrom Running

Rikugun

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Lucky

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Re: Mac exhaust
« Reply #17 on: March 29, 2012, 04:04:43 PM »
when you pull that right cover your supposed to replace the oil sel in the cover (good idea after 30 years anyway) did you replace yours? iirc, it feeds the main oil gallery...
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1982/3 XZ550 Touring Vison, Gold on Black

artbone

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Re: Mac exhaust
« Reply #18 on: March 30, 2012, 06:33:20 AM »
I saw that exhaust system on ebay and would have bought it if the guy would have at least painted it. I think I would rather wait a few weeks and get a new part instead of bolting some rusty, bent-up, homemade POS on my bike. I mean, the bike looks pretty rough anyway; why make it worse.

And, no, I didn't change the oil seal. To tell the truth, I didn't even see the oil seal. I didn't have my manual with me so was just working blind, so to speak. I think the bike has an oil light and, when it cranked, all the lights went out except the neutral so I'll have to assume it is okay. I'll pick up a new seal before I head to Barbers. Now that I've taken the cover off it will be easy to do the next time (and I'm sure there will be a next time.)

Rikugun, did you get my message about the picture of the black Vision with the dual projector beam headlights? I want a better look at the seat. I have a seat with a torn cover that I want to make into a monoposto seat.
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'06 Suzuki VStrom Running

artbone

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Re: Mac exhaust
« Reply #19 on: April 10, 2012, 07:11:42 AM »
Are there any alternatives to the MAC exhaust system? I'm getting tired of waiting for them to get some made. Or does anyone have one they would like to sell?
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'06 Suzuki VStrom Running