Changing Exhausts

Hey everyone,

I am looking to purchase an Mac 4 to 2 Exhaust for my 1983 XJ1100. Will I need to rejet the carbs to make this good or is it close enough to stock not to worry about it.

What other option is there for our vintage bikes other than Mac Exhausts?

Thanks...

 

Most aftermarket exhaust flow better than the stock ones. It will run fine on your bike with stock airbox and airfilter. Keep a check on your plug color you might need to go up one size main jet.
There are not many exhaust systems available for the XS/XJ1100's. I found one I want overseas but it is way to expensive. Once in a while you can find a NOS set on EBAY. I don't like the look of the MAC system so I am waiting for the right one to find me.

 

I had the same question, but I have removed the stock airbox/filter and replaced with the pod filters. Does that change anything really or should the same jetting be ok? Doesnt really help that I bought the bike with a Jardine 4-1 so I am not even 100 percent sure if the bike has stock jetting currently. I am assuming so though. I bought a Mac 4-2 to replace the Jardine system as I like the look better.

Also (I feel pretty dumb asking this but...) where do you buy different jetting kits for the bike? Is that something Chacal has?
-Dana

 

Not sure about the Mac 4/2 pipes, but I know the Jardine 4/1 on my 750rj required major increases on both the idle and main jets, with seemingly endless (although sorted out now) adjustments to sync, mixture, and float height. I replaced the tiny original Jardine can with one off a Suzuki 750 (GS?). The pods vs. airbox issue has been flogged repeatedly in the forums, the general concensus (after much heated debate) being that pods are going to make it extremely difficult (impossible?) to tune your carbs, as they are designed to operate with a small amount of intake air restriction. Intake air tuning on my bike required a K&N filter and drilling holes in the airbox, down into the 'toolbox' area, which was then stuffed with filter media and screened. I would wager that the first time you start your bike with the pod set-up (if it starts), you're going to encounter some very serious lean 'zooming' at idle - be ready with a finger on the kill switch - mine zoomed to redline more than once in the early days of carb tuning! Good Luck!

 

I'm in the same boat as the OP...I just picked up a '79 xs1100 Special; the PO lost one exhaust baffle on the highway, then he drilled the second one out Sounds like total @ss, is really loud, and has played merry hell with the performance of the bike. I'm hoping a decent exhaust with some restriction, getting my carbs to pass the "clunk test", and a carb synch should get me closer...

 

what is the effect of having no baffles , performance wise, on the motorcycle? I purchased my xj650j without any baffles. the previous owner replaced it with a sawed pipe. its my first bike, and i really can't find much parts here in our country.

 

And which country is "our country"? Fill in your profile to make it easier for forum members to help you sort things out.

Loren

 

Exhaust mods are always sketchy at best. In my book 4-1 headers and a super trapp is probably the best way to go. The exhaust sound and fume waves reverberate in the exhaust head tubes and too short in length or large in diameter will kill your low end and cause you to lean out. Too long or skinny may give you a boost in torque 3000-5000 rpms but sacrifice your top end. The perfect goal is to have the wave reverberate the unburnt fuel back into the cyinders before the intake exhaust valves close but the exhaust wave length varies with rpms just like sound waves do. I've done alot of experimenting and constantly fiddling with the jetting. The air filters are a factor too and pods are for racing mainly, yeah they look cool but how may times will you have to take off the carbs before you get them dialed in? Headers with supertraps are better because their are restrictor discs you can change to adjust the power (torque) band to just where you want. If you can afford them, I'd go with them.