Better and Why 4 into 2 or 4 into 1

I need to replace my exhaust on my 81 XJ650 Maxim. I dont understand the difference between the 4 into 2 or the 4 into 1. Can some one help me understand which I should chose.

Thanks

 

I replaced mine with a Mac 4-2. Someone with more knowledge than me will chime in here, but I believe a 4-1 would require rejetting in order to get your bike running right afterwards. A 4-2 would not necessarily need it. My bike is running a little rougher (popping an backfiring) after installing the 4-2's but I had preexisting carb issues that need to be resolved.

 

If you replace the exhaust with a similar exhaust (4-2) then jetting should not be an issue, not sure if the Mac breathes freer, but maybe can get away with some tuning. However, if you do go 4-1 then you are altering the way the bike breathes and will have to re-jet, which entails a carb tear down and unless someone has the same set up you may have to try several jet setting to obtain optimum performance.
If you are comfortable playing with carbs and settings you should be fine, but if you need a shop or have to pay someone to do the work, the money will fly out of your wallet faster than a V-Max on Nitro.

 

I could do the carbs but it was not something I really wanted to do. But my questions were more to what is the advantage of one over the other.

 

4 to 2 will offer similar performance characteristics as the stock system. A 4 to 1 system is going to trade low end torque for high RPM horsepower. Because the system flow different at higher RPM, the jetting then will be different.

Hope this helps.

 

Thank you I want to stay in the high HP riding the twisties. How about ground clearence. is there any difference anyone knows of besides there is only a pipe on one side.

 

Most bikes will usually start grinding the footpegs before the exhaust, and I don't think you'll have to worry about that problem on your bike, so ground clearance should not be a problem.

 

You just have to worry about speed bumps (like parking lot) with the 4-1 it won't drag leaning. i like the sound of 4-1 better, and gives more power. As far as rejetting it might not be necessary, depends on the system and other variables with your bike/location. Backpressure is a good thing.

 

indeed. the 4-1 is lower but only in the center so it doesn't effect leaning deap in the twisties. The weight savings of 1/3 - 1/2 as much muffler and a lighter header is nice but unnecessary. The 4-1 header makes oil and filter changes a pain.
I park on a lot of sidewalks and don't have trouble with the header scraping when I just ride off a curb but tall speedbumps hit at the wrong speed will a bit. Your results may vary.

 

Man... did my first oil change last week-end after my crankcase got flood with gas and yes:

1- when draining, oil dropped on the headers. So I won't consider wrapping them;
2- removing the filter was a pain in the b***

 

It's also a matter of whether or not you want the symmetry of a pipe on each side; or if having one big one up the right looks ok to you. Personally, I like having a pipe on each side.

 

I had a 85Maxim X with 4 in to 1 HINDLE. It sounded awesome. Had lots of compliments. Sold it. Wish i kept the Hindle for my 86Maxim x. I would anyday prefer a 4 to 1. I dont know if you can get your hands on a 4 to 1 for your bike thou. By the way i never had to rejet. I did carb clean and tuned it myself, ran like a champ.

 

If there is no collector box, you will have to tune tune tune. Doesnt matter if its a 4-2 or 4-1. When you change your exhaust from the stock set up, expect to have a lot of fun. I'm STILL figuring out my MAC 4-2 Slash cut. Maxine will never run the same now.
Oh but
Yay.... Sounds good.

 

My 83 XJ750 Maxim came with a Mac 4to1. The carbs have the standard jets BUT I had to turn the mixture screws WAY out to get the proper mixture setup. I have a second set of carbs that I'm going to rebuild and re jet to see if it makes any difference.

 

I had built a 4-2 custom exhaust and didn't like the sound, so I put a crossover in it. It made a world of difference for sound and torque. I would never run without some sort of H pipe or crossover. Fitz is right about the magic box, if you want max performance.

 

Just threw a set of Mac 4-2s on Shirley with no tuning issues at all. She pops just a bit when using the engine to slow down but nothing crazy. Performance doesn't seem to be affected, she sounds like a beast now though.

 

Best solution I found for oil changes with any exhaust set up is get a roll of tin foil and just wrap the pipes and anything else that the oil has a tendency to spill on. After the oil change just remove the foil and "TADAAAAA" no oil soaked pipes or nuthin!
The Hindle has a nice opening between the pipes for access to the filter, least on mine it does.

 

ah nice. I ride super rat so I just let it spill and make a cloud !!
That's how my bike got named Pigpen. I pull up to a stop and moments later the cloud arrives.

Maybe a custom funnel of some sort.

 

Nice trick! I'm taking note...

 

LOL. I like