straight pipes???

seems lots of people straight pipe their xjs but got told today that it will burn my valves.. anyone got any input?

 

Guys put straight pipes on bikes like Harleys every day, and never have a problem with it. Why would an XJ be any different? I think if you cut the pipe to short you might have a problem.

 

It's loud...beyond anything you could imagine a harley to be. There's twice as many cylinders and twice as many rpm's, leading to 4 times as much volume at speed, and a totally different, persistent, annoying sound. It's not so bad at idle, but I couldn't live with it so loud. It's hard to take it up to speed because you feel like it's going to explode underneath you. I don't think all that many people do it, really, and those that do, do because they don't realize how annoying it's going to be.

Mechanically speaking, which is really what your question is, XJ's are a LOT different. We have one carb per cylinder, a lot less volume per cylinder, and a YICS system that allows the bike to run much leaner. And it's not that the pipes themselfes will burn valves...it the extremely lean exhaust gas that heats up the valves and causes problems with warping, etc.

You can re-jet it back to safety....but that's a whole lot more difficult and expensive with 4 carbs.

 

Not to mention an XJ motor and a Harley motor are completely different motors.

I think I remember the problem was that the pipes need to stay hot enough to push the exhaust out and some say the straight pipes would cause a problem.

I have seen a few members do it and they report absolutely no problems with it

 

I am trying to get rid of mine, besides the noise it's im-freaking-possible to tune.

 

I imagine doing it by ear would be very extensive.

 

Thanks for the feed back yall. very much appreciated. i took my carbs off yesterday got them all cleaned up and synched. put it back to gether and decided to pop my kerker off. i agree it is quite a loud one at speed. could i just take the packing out of my kerker keep it louder then the kerker but no as loud as it is now? and that would give it some back pressure as well.

 

These bikes are notoriously difficult to tune. They're probably not any different than other 4 carb/ 4 cylinder bikes, but there's a lot of parts that affect the tuning.

What I'm saying is, do what you want to make it sound how you like it...

...but be prepared for it to be very difficult to tune.

You can get it well tuned at any given engine speed....just not all of them unless you're either stock or really good at tuning carbs.

But if all you do is ride it every other weekend for an hour with a group...and sound is more important than useability...go for it.

 

Or you could send me out your kerker (crosses fingers)

 

i just put it back on for the time being. once i fix my truck an can park my bike and build it how i want it id gladly give ya my kerker but you would have to pay for shipping

 

Hello all, I know this is an old thread but I just bought a XJ650J and saw this thread and was wondering if the straight pipes would cause any mechanical problems in the long run and or short run, I plan on going on rides with my buddy but want a louder bike and dont want to spend the money for an expensive exhaust. But I also want to make sure I dont hurt the bike, seeing as I plan on keeping it for a while. Thanks for the help.

 

Ive got a short turn down tip on mine to try to limit the noise. For sure its loud but no were near my neighbors harley. I havent had a lick of problems with it and ive got 40k miles on mine.

 

Thats cool I was thinking of either straight piping it or I also found a thread about drilling holes in the existing baffles and running it that way. I just want the bike to last a while. You didnt have to jet the bike or anything did you? I really dont want to get into that.

 

So I have been reading on other forums and on other threads, If I do run the straight pipes does anyone know what I will need to re jet the carb? or if I will have to do it at all?

 

I've run mine without mufflers for awhile now. Plugs do not show a lean condition and I did not rejet.

I have a feeling I will need to though with my future setup.

 

my plugs are slightly rich and im still at stock jets.

 

excellent news i guess lol. How long have you guys been running your bikes like this? and Should I extend my pipes to equal the length of the mufflers after I take them off? Im gonna pull them this weekend and see how she sounds.

 

I have mine only about 6in beyond the collectors, pretty much inline with just behind me.

 

Do you have any pics? I would like to see how it looks.