Aftermarket Exhaust

Does anyone have a rough guess-ment on horse power gain by installing a aftermarket four-into-two exhaust system. My bike is a 1985 XJ750XN. Not that it really needs any more, just wondering if they are worth what they cost. I can't see where there would be much gain over stock,but it would not be the first or last time I was wrong. Any input or thoughts would be great. Thank-you.

 

Roughly zero.

Altering only the exhaust will likely move the powerband around, but not change the actual output (other than to possibly lower it.) To actually gain anything you would have to make corresponding changes to the intake system as well, and then re-tune to take advantage of them.

The usual reason for going to an aftermarket exhaust system is the high cost and relative scarcity of the stock parts. Often it's the only readily available option.

 

Thank-you Bigfitz. That is kind-of what I was thinking. I cannot see spending $400.00 on something I really don't need. I did put a K&N air filter on so I will have to re-jet it. But I have a color-tune plug so that should help me do that.

 

Here's what I put on my XJ many years ago. It's a Hindle factory system and I put it on for the same reason as most.....COST.
I have a note in my manual and all it says is Main jets #120, according to Hindle there was supposed to be no jetting changes, but within minutes of starting it the header turned blue. I do remember (barely) taking the carbs off a few times until I ended up with the 120's though.
Also, the whole system from front to back probably weighs less than ten pounds.

 

Thanks Maxim-X. That is what I was looking for, someome with the same bike as mine that has put a system on. Did you notice much of a change in power. Its pretty hard t tell if your bike is tuned good. They tend to pull hard above 6,000rpm stock. That was one of the things that impressed me the first time I rode one.

 

wish i could find an exhaust like that for mine really like the looks

 

Well, I went through my files and found the original receipt from June 17 1999.
The front section part number is/was HI YX750 and the can is/was HI GPR182.
I ordered the system through a local dealer on March 28 1999 and finally got it on June 17 1999.
The front was $299.99 and the can was $249.99, with taxes it came to $532.40, which at the time was still over $400.00 cheaper than a factory system from the dealer where I bought the bike.
I looked on Hindles site and ran the part numbers but came up with "No listings found"
I guess you could contact them with the part numbers and see if they can still make the system or substitute parts.


Cheers, Graham

 

yea they discontinued it long ago as all the header companies did. Guess the bike is to old. I have a 4-1 have to replace the muffler wich is not a problem just like the ss look better then painted black

 

Oops, forgot to address the question about power. I did take her down the drag strip a couple of times and my best run was 12.06 seconds at 110 Mph.
But the best and most fun I remember was the time I went out with some guys from work. Two guys had CBR600's and the other had a Ducati 750 (something or other) and me on my X. We just filled up at a gas station, pulled out on the road and gunned it, when we got to the stop light Don (on a CBR) pulled up beside me totally shocked that I had passed him with the front wheel about three feet off the ground.
Top end they could eventually leave me behind, but I could pretty much keep up to them up to an indicated 200+ Kmh then they would pull away.
If there was one thing that I would have ever change on these bikes would be from shaft to chain, then I could play with the gearing.

 

hey maxim x your radiator fell off lol you must have been painting

 

Ha, ha.
Actually, that's been off for years. I keep telling myself that I'm going to get it back on the road, but something always comes up. I've had the bike since day one and I'll never part with it, so one day it will run again.

 

doesn't do them any good not to run even if you don't drive it. But i know what you mean My x has sat since last summer i drained the gas out of the tank and ran it till it wouldn't run. Went to fire it up a few months back wouldn't start. I am polishing and replacing a few things will clean the carbs when i put the new airbox on.
I am on break for a few min working on my pos virago. Swapped out hitachi carbs for mikunis they worked great. Then i had my health problems it sat for 4 months. idle jet plugged. Pulled them off fixed the jet put them on again ran good sync the carbs then the float stuck. Tapped on the float bowl got it freed up was running good then the float got stuck in the up position on the other carb. Got it freed up was running good in the garage then the other float stuck again. Hate to do it but i have to pull the carbs again. I would rather r&r 5 sets on a inline 4 then 1 set of these you have to pull the intake boots to get the carbs off. Be glad when i get this done and sold.

 

I feel the same way about my X,don't think I would ever get rid of it.I have had mine since 1989. My younger brother bought it new and put the first 10,000 kilometers on it. When he died in 1989 his wife willed it me. Come to find out that is the only way that you can legally import them in to the U.S. and get a waiver from the EPA. There is no EPA spec for them. I contacted the factory after the first time I tried to get it through the border, they noticed there was no EPA sticker on motor & said I need to contact EPA in Washington D.C & apply for a waiver,what a joke that was. Took forever for them to reply. So I have not been able to ride it as much as I would like to has 25,000 kilometers on it now, which is only about 15,000 mile low for that year of bike.
This fall went through carbs,put petcock kit in,K&N air filter,brakes front & rear,still need to put SS lines in front,rebuild master cylinder & calipers. They are so fast good brakes is a must.