Swingarm Brace vs Crossover tube?

Near the engine cross overs were all the rage for a while, so were air forks LOL.
I ride a stock 79 standard with the crossover and one with MikesXS commandos A-B, can't tell the difference. Except the stockers sound a bit better (lower tones)
Since the XS is 360 firing, the crossover theoretically doubles muffler volume, halves exhaust velocity. For great sound nothing else touches the early, no cross over, baseball bat mufflers. So THERE! :twocents: I'd take a stiffer swing arm over the crossover. That said I have a TX750 AND a radian swing arm and haven't put either one on a runner yet. :lmao::eek:
 
Jack said:
NO,the balance tube's job is to aid in balancing out the imbalance pressures of the cylinders to enhance
scavenging which in return boost low and mid range performance and lowers exhaust tone.
Click to expand...

Jack,
That being said, doesn't the same science that sized the exhaust headers apply to the crossover?

Back pressure is a bad thing. Scavenging is good. Smaller pipe scavenges faster until it's too small. I'm no good at explaining the science, especially since I haven't worked in it. I'd leave it to Jack. Any chance to speed up the exit of exhaust gas is a good thing.

The swingarm brace looks real nice. Isn't the weak point back there in the frame? I believe the brace is needed across the swingarm pivot on the frame.

I once had a lot of ideas about improvement to the XS650. Every time you make one, you run into another shortfall. I've decided the XS650 can benefit from modest improvements, but may be best enjoyed as the engineers designed it. For performance, the smart money might go pick up an FZ-09. JAT
 
gggGary said:
Near the engine cross overs were all the rage for a while, so were air forks LOL.
I ride a stock 79 standard with the crossover and one with MikesXS commandos A-B, can't tell the difference. Except the stockers sound a bit better (lower tones)
Since the XS is 360 firing, the crossover theoretically doubles muffler volume, halves exhaust velocity. For great sound nothing else touches the early, no cross over, baseball bat mufflers. So THERE! :twocents: I'd take a stiffer swing arm over the crossover. That said I have a TX750 AND a radian swing arm and haven't put either one on a runner yet. :lmao::eek:
Click to expand...
Thank you for your considered input.
At this point leaning towards aftermarket look-a-likes and place the OEM's in the back of the barn.
Suggestions for aftermarket "baseball bats"...
Anyone, anyone...
 
jetmechmarty said:
once had a lot of ideas about improvement to the XS650. Every time you make one, you run into another shortfall. I've decided the XS650 can benefit from modest improvements, but may be best enjoyed as the engineers designed it. JAT
Click to expand...
Wishing I'd skipped the brace and only replaced the bushings....live and (hopefully) learn.
 
I also agree with marty there is room for a frame stiffening brace between the swing arm pivots that should help reduce flex back there. Gotta build up an engine then maybe a modded frame........... so many projects....... Sure there are awesome later model bikes going for a song, there's an 04 FJR in the shed this winter, but the oohs and ahhs STILL go to the XS650s!!
 
Nothing beats the sound, or performance, of a stock 360 degree engine with stock exhaust, complete with crossover. Combine that with the stock airbox, and it's a smooth running engine. Yamaha engineers knew what they were doing.
Sure a beefed up swingarm is great for racing, but for street use, the stock exhaust is the best choice.
 
650Skull said:
Cut the tube and plug, do it in such away it can be rebuilt if wanted. never had the experiance of the difference on the same bike. A friend has a C and had a set of aftermarket C-F mufflers without the crossover. Found a set of NOS C-F mufflers with the crossover, and without any other changes to the bike, he said it ran better and seemed to smooth out the rough edges..............he rode the bike to work every day so definatly had recent riding as a gauge.
Click to expand...
I'm confused....friends bike runs better with or w/o crossover?
 
Roco22, I have removed the crossover and plugged the holes with 1 1/16" freeze plugs on an '81 special. It made no difference in performance that I could tell.
 
Roco22 said:
Can ya give me a link...no can find...Thanks
Click to expand...
Here you go just scroll down. I personally would of gone bigger for greater flow. You want the tube close to the port like this to take full advantage of the scavenging pull on the port. There are no formulas that I know of that would suggest what pipe size is the best for effectiveness,trial and error would come into play.
http://www.xs650.org.au/Visitors Bikes/visitors_bikes.htm
 
The exit tube from each muffler has a plate welded at the end in aside the mufler. You can knock off this plate and the sound and flow will increase. I loved thwesound from my stock 77 muffs with the plate knocked off. People would ask with great respect, "Is that the original muffler?" Yes, they sound good! I did have the crossover.

The crossover is to have each cylinder go through both mufflers. Less restriction and more souyn surpression.

Tom
 
Tomterrific said:
The exit tube from each muffler has a plate welded at the end in aside the mufler. You can knock off this plate and the sound and flow will increase. I loved thwesound from my stock 77 muffs with the plate knocked off. People would ask with great respect, "Is that the original muffler?" Yes, they sound good! I did have the crossover.

The crossover is to have each cylinder go through both mufflers. Less restriction and more souyn surpression.

Tom
Click to expand...
The exit tube from each muffler has a plate welded at the end in aside the mufler. You can knock off this plate

Not following what your describing...
Where exactly is this plate I should knock off?
 
My stock mufflers had this done by the PO. I found out the construction by using a probe inside. Stick a probe, a large punch, inside the muffler. Does it hit a stop about 8" inside? This is the plate to be knocked loose.

The exit tubing in the muffler has a few small holes drilled in it. These holes are the path the exhaust must take. The sound is surpressed by the restriction of the holes. Knocking the cap off the inner end of the exit tube gives the exhaust a freer path.
 
Great Info.. Ironic to me as I've been so happy with the exhaust tone of my stock 78e like Roco's. So I looked in there to see how to knock out these plugs.. Ha,haa my old exhaust is just enough corroded that these plugs have all but blew out on their own ! Yup, the exhaust tone is Fantastic !
 
TimeMachine said:
Sounds like it requires removing the mufflers first ? Is that so ? Otherwise this plug would be left to rattle inside ? That's what I'm hearing.
Click to expand...
Hi TimeMachine,
I gave my '84 Heritage, my son's '80 Special and a pile'o'parts rebuild '79 Special the same on the bike pointy bar bafflectomy.
What I reckon is the restriction disc is tack-welded onto the end of the baffle tube in 3 or 4 places so that the pointy bar hits pop
the welds apart one at a time until the last one acts as a hinge to let the disc open but not rattle around loose.
 

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