'82 Seca XJ650 under engine exhaust

I just picked up an 82 XJ650RJ, and I am looking to modify the exhaust and would love some feedback/suggestions on how to proceed. I really like the look of under-engine exhaust, and also looking for a bit more noise and growl than the current stock exhaust. I have read a fair amount of threads on the stock exhaust and how well designed they are. Don't want the screw up the performance, but I am looking to make a change here.

I'm a bit of newb to bike mods, but handy and capable. Not afraid of a project, but also not looking for a huge expensive adventure.

Any advise on where to look for ideas, parts, approaches for this would be very much appreciated!

 

Start by mking it run perfectly before you do any modifications, so you have a good baseline to compare to.

Safety items count.
Valve clearances matter
Carb cleanliness matters

 

Definitely good advice. It runs like a champ. Great condition - starts on a dime. Just took it on a 200 mile ride in the foothills outside Denver. Besides some cosmetic issues, I feel there's a good baseline here.

 

OK.

Plug colors look good? Valve clearances are in spec? Carbs synchronized?

The XJ series of engines seem to run perfectly to most people, until they get it tuned correctly, then they realise how good it really is.
I'm not saying that your's isn't prefect, just that it's wise to double-check. The XJ loves to run lean, right up until there is a hole in a piston. Exhaust mods will tend to cause it to run even leaner. Play things safe.


Speaking of safe. The brake lines don't happen to be about 34 years old do they? Check the date codes. Brakes > engine.

 

^^+1 agree with k moe.... One thing I would suggest rather than cut up exhaust if yours is in good shape... buy a header , and modify it instead this way if you don' t like it you can put original back on.

 

Or sell the original to someone like me!
Alan

 

Plugs are good. Next step per your advice K-moe is to check Valve clearances and assure that the Carbs are synced.

Cheers,
Keith

 

Jetfixer - any advice on where to source new headers for this old bike? Does anyone sell ready-to-go header pipes, or am I looking at custom work?

 

MAC makes full exhausts, and might sell separate headers.
Marving also makes full sets and they appear to be reproductions of the OEM system. I don't remember if they sell headers seperately or not though. I do know that Marving is reported to be of better and more consistant quality than MAC is.

Then there's E-bay. Used haders are fairly plentiful, and sometimes even inexpensive.

 

As for an under-engine exhaust. You could build one based on the stock collector, bu tenlarge it a bit and add baffles.
Or you could put some shorty cans directly on the collector outlets. I think there's a few pics around here somewhere with that setup