New MAC 2-1 exhaust

[incarceration]

With the right sized allen key (mine's about two inches long or shorter), you can remove the float bowls with the carbs in place.

That allows you to swap the pilot and main jets out.

With the tank off and a longer allen key (I have one about 4 inches long or so), you can get the diaphragm covers off and carefully lift the slides up and out from under the frame top tubes again with the carbs in place.

I was sure I had a photo of taking the float bowls out but can't find it, however here's one showing the slides fit out under the frame rails:

Awesome! Thanks Pete.
Which parts exactly did you service\replace while leaving the carbs on after replacing an exhaust system?

Would have to use this:

http://www.ebay.com/itm/Suzuki-GS450-GS-450-cc-S-T-L-E-Twin-Custom-Carburetor-Carb-Stage-1-3-Jet-Kit-/231051293135?pt=Motorcycles_Parts_Accessories&hash=item35cbbaf1cf&vxp=mtr

if my bike is running too lean after the exhaust replacement? It sounds like I'd have to take the carbs off for all of those parts lol

[Guest]

I was able to do all adjustments with the carbs in place.

Pilot jet, needle adjustment, main jet, and I was able to do some slide modifications.

For yourself, I would be very careful with the Sigma kit, I have heard many mixed reviews, and a lot of people have to go back and forth with several different settings to get a setup that works. The seller intends to do the right thing, but from what I have been told he seems to get it wrong as much as he gets it right.

Also, to just make the bike right for a new exhaust, you don't want slide modifications, you only want jet and needle changes. Reading that kit leads me to believe you're going to enter a world of pain.

As far as getting the right kit for your bike, you need to be very careful with the 450's as the carbs were the same 80 - 82 but then changed in 83.

I just realised yours is an 83, so you should be able to get a proper quality Dynojet kit for it.

[incarceration]

I think it's an 82, the frame says 82 but the title says 83 and there have been things with it that are from 83, so I'm not sure, but the frame says 82 lol.

But you do think I'm going to have to redo stuff after the exhaust replacement? I didn't see any other kits, let alone just jet and needle kits

Thanks for the help!

[Guest]

Think the most you'll have to do is up the main jets a step or two. If you add a K&N air filter, maybe 3. Watch the pipes and do the plug chops to confirm. While you are at it, check your carb boots to make sure they aren't cracked and hard, front and back. If they show any signs of being bad, replace them. It will prevent a bunch of headaches down the road.

[incarceration]

Finally got the whole bike fixed up this weekend. But now it doesn't go over ~40MPH happily. It's like it lost all of its power.

Is this because of it running too lean?

[tkent02]

Probably. What jets did you use?

[incarceration]

I haven't been able to find any let alone order any :\

So the jets are the original jets from before the exhaust\muffler exchange.

I saw you suggested 'Dynojet', where can I find those and which parts\pieces do I need? I remember you saying the 'main jet' but can't remember anything else.

Thanks in advance.

[tkent02]

Just order Mikuni jets from Z-1, they are only $2 ea so get a range of them from one step bigger than stock jets to about three. Start with the biggest, work your way down. Plug chops and seat of the pants will tell you when you are there. Then adjust the other carb circuits from the top down. If you are persistant you can get it perfect but it takes time and effort. You may need Dynojet's needle, maybe not.

First step is to read up on how the carbs work and Mikuni's procedure for tuning them.

Don't ride it until you get bigger jets in there, burnt valves are expensive.

[incarceration]

I'm looking and don't find my exact model bike in here:

http://www.z1enterprises.com/ShopByCategory.aspx?name=GS450&description=Suzuki+GS450+448cc+4-cycle+twin&category=0101040203

Can you help me find the needles I need? Because I don't even see any needles for sale on that site for '82-'83 GS450L model bikes

Lol and what the heck does "...and seat of the pants will tell you when you are there" mean? Btw, I thought to 'plug chop' you had to ride it then cut the engine and pull over and check the plugs? How do I 'plug chop' without riding?

[tkent02]

When it runs perfect you will know it. When it won't go over 40mph it's not running right. What I said was don't ride it before you put in bigger jets.
You put in bigger jets, then you ride it. Pay attention to how it runs, and look at the spark plugs. You may not need any needles, maybe just raise them up a tad. I dunno, never tuned a 450. But I have tuned a lot of GSes, some of them with CV carbs.


Do you know what size jets are stock for your bike or what is in it now?
Did you find the 450 tuning reference from Pete? Did you look at the list of stock jetting in the carburetor section?

Just changing the pipe alone it should not be that hard to get the jetting right.

[incarceration]

You may not need any needles, maybe just raise them up a tad.

How so?

Do you know what size jets are stock for your bike or what is in it now?
Did you find the 450 tuning reference from Pete? Did you look at the list of stock jetting in the carburetor section?

Just changing the pipe alone it should not be that hard to get the jetting right.

- Do I know what size are stock? No, but I found this info on here that I will post below my responses to this quote.

- Did I find the 450 tuning reference from Pete? I'm assuming you're referring to Pete's response earlier in this thread where he told me to get a dynojet kit? I don't see any place online selling just the "main jet" and "pilot jet".

- Did you look at the list of stock jetting in the carb section? Yes, that's where I found something related to your first question, I believe.


Info found:
US 450 models:
Make: Mikuni
Type: BS34SS
Venturi Size: 34mm (1.34 in)
ID number:
ED: 44400
LD, TXD, LF: 44460
Other models: 44110
Idle Speed:
ED, LD, TXD: 1200 +- 50 RPM
Other Models: 1200 +- 100 RPM
Fuel Level:
ED, LD, TXD, LF: 5.0+- 0.5 mm ( 0.20 +- 0.02 in)
Other Models: 6.5 +- 0.5 mm (0.26 +- 0.02 in)
Float Height:
ED, LD, TXD, LF: 23.0 +- 1.0 mm (0.89 +- 0.04 in)
Other Models: 22.4 +- 1.0 mm (0.88 +- 0.04 in)
Main Jet:
ED: 120
Other Models: 115
Main Air Jet:
ED, LD, TXD, LF: 0.7
Other Models: 0.6
Jet Needle:
ED: 5DX87
LD, TXD, LF: 5CDT60
Other Models: 4C2
Needle Jet:
ED, LD TXD, LF: 0-6 (O-6??)
Other Models: Y-6
Throttle Valve:
LF: 95
Other Models: N/A
Pilot Jet:
ED, LD, TXD, LF: 45
Other Models: 17.5
Bypass:
ED, LD, TXD, LF: 1.0, 0.8, 0.9
Other Models: 0.8
Pilot Outlet:
ED, LD, TXD, LF: 0.7
Other Models: 1.1
Float Valve Seat: 2.0
Starter Jet:
ED, LD, TXD, LF: 32.5
Other Models: 30.0
Pilot Screw Setting:
ED, LD, TXD: Preset (2.0 turns out)
Other models: Preset
Pilot Air Jet:
ED: 135
LD, TXD: 145
LF: N/A
Other Models: 1.6
__________________


Thanks

[tkent02]

OK, what jets are in your carburetors now?

[incarceration]

As of now I do not know.

How would I find out what they are? Do I have to pull the carbs off?

I have replaced the screws throughout the 2 carbs with allen headed screws, can I remove the float bowl without taking them off and tell you this information?

[tkent02]

According to Pete you can.

[incarceration]

Ok which jets do you want to know about? And please tell me roughly where they're located because I do not know them by name - I have a Clymer's manual that I can reference the names and locations though. Also, how will I identify the type or specific jet?

Thanks