Jetting kit on 1981 xj550

Ok so I bought a xj550 off of one of my buddies. Turns out he didnt take care of it the way he sould have. It needs some work but nothing that I cant handle... I think. anyways one of the things I am looking to do is take of the muffler and run it as straight pipes. Its a 4 into 1 exhaust. My question is what will i need for the carbs so the motor wont run too lean or too rich?

 

Don't do it. Do you have ANY IDEA just exactly how rudely LOUD it will be running a 4-1 open? I know, my '81 came that way, with an open Kerker on it. You could LITERALLY hear it a mile and a half away. Your neighbors will hate you and you will drive yourself nuts trying to tune it. TWO complete XJ550 (Max) exhaust systems have come and gone on Ebay in the last two weeks. Maxims are easier to find than Secas, you didn't specify. If you really want to enjoy the bike, put it back to stock.

 

Ok well... thats doesnt sound like such a good idea afterall then. Well then what could I do to get a little bit of a louder sound out of the exhaust and also what would I need to rebuild the carbs if I want to put filter pods on?

 

Some folks here have gone with sporster mufflers.
Seems to be the inbetween that you're looking for.
When you add pods you set yourself up for the same hassle with tuning as you would of had with open headers.

You are looking at putting bigger jets in to compensate for the huge amount of air you've introduced.
Problem is it's trial and error, try this set not right, try the next ect...

 

Agree with the Hound,
it took me almost a year to sort out the carbs after all my changes made. For me it was worthwhile but as a good advice, don't start. Don't even think about it unless you have a lot of money and a lot of time

 

Spoken like an experienced pro.......

 

Thank's Chacal But I'm not a pro. I just summarized the experience with my bike

 

Some opinions from a non-tech.

I'd bet money that you lose horsepower by going to a straight pipe setup. More than a few people have learned that those pipes actually do better with the baffles in place and packed.

If you're stuck with running that 4 - 1, I'd still check the jetting before running it lean and screwing up the motor. :wink:

BTW, I'm in the same boat and the seca I just got has a 4 into 1. I don't plan on riding it until the pipe/jetting is sorted out. I can already visualize fried valves adn time will tell.

 

I would imagine a jet kit would be necessary when altering the exhaust to that degree. If it already has a 4 into 1, I would think there would have to be already some kind of jetting kit on there? Unless that's a stock option I'm unaware of. As one of the other folks pointed out, you'll lose HP for sure going straight. Loud pipes, in my opinion, are good especially so you can be heard (if not seen by drivers) however, I'm sure that's probably not a viewpoint everyone shares!

 

...Loud pipes save lives

 

Since when do drivers notice motorcycle riders around them? I for one since I have started riding give more then enough courtesy to motorcyclists on the road. By the way Crath did you have to rejet your carbs?

 

Yes, I rejetted them 118 mains and 42 pilots