4-1 or 4-2, What exhaust do I want?

Right now I have a stock 4-2 exhaust on my Seca but I can swap it for the 4-1 pipe that is on my brother's bike, I think it is a MAC exhaust. Will I gain anything by swaping the exhaust? I doubt the power difference will be anything but what about weight or anything else? Does anybody else run the MAC 4-1? I started up his bike and it didn't sound much different then mine, maybe a little louder but his bike doesn't run very well.

 

With jetting and pods, you can gain a bit of horsepower, but a 4-1 tends to sacrifice a bit of power down low for some gains up top. It probably weighs a bit less too.

 

Can I run pods with the stock carbs? I have heard that it is very hard to set up the with the stock CV carbs.

 

Its not that they wont run with the stock carbs, it's that now your exhaust is breathing so much easier and so is your intake with the pods. Since you are getting so much more air into the engine and not any more gas you need to go up probably 3 sizes on your main Jets and maybe raise your needle a bit by putting a .020 shim or washer under it. Stock carbs are set up for a specific fuel to air ratio and now that you have more air coming in and going out that ratio is not what it needs to be. Your engine will run hotter than it should and will most likely shorten its life if its not set correctly. Now you are asking me how do I know if its set up correctly, That's what the message boards are for we can try to help
Ohh and what is involved in changing the jets, well that's pretty easy, if you have a couple of screwdrivers and maybe a hammer you should be able to change out the jets. Again look online for that info.
HTH
Sean

 

You should only consider the 4-1 if you're happy with the condition of your carbs (squeaky clean and well sealed), and have the time and patience to sort out the jetting. There's several different jetting techniques, but for each jet change you're gonna have to remove and replace the carbs, remove and replace the jets, adjust the float levels and/or needle heights (at least once), synch the carbs, adjust the mixture screws, then ride the hell out of it, taking note of specific rpm and throttle settings. Not difficult, but certainly time consuming. A good technique is described on factorypro.com. if you'd like to preview it.

I don't have the MAC 4-1, (mine's a Jardine) and what I found is substatially improved throttle response, crisper acceleration, and a much more even power band - AFTER JETTING. Before jetting I was lucky to get it to idle. Just hanging a 4-1 (or any exhaust differing from stock) will almost invariably result in poor idle, mixture problems, and generally lower performance than stock. Its one of those things you just can't do half-way.

 

I have a MAC 4-1 canister system. I put it on my 750 Maxim and it has run smoothly and consistently with no other changes, except UNI foam filter in the stock airbox. It's been this way for about 2 years, and I think it still has good power all the way through.

The only check I've done is for spark plug color, and they look pretty healthy in my opinion. All this talk of taking carbs on and off and all the testing and work, just doesn't sound fun to me. I have 3 project bikes and the Maxim is the "get on and ride" bike.

I'm pretty sure gains could be made if someone took the time.

BTW, the bike is for sale, check the for-sale forum. I'm moving and not taking the bike with me. Make offer.

Also, I'm attaching a pic of the internal baffle in the MAC 4-into-1 system for those curious. It is too LOUD for me, I want to commute to work at 6am without pissing off the neighbors.

 

brad020 , you could have stuck some fiberglass in the baffle....