Figured I should introduce myself.

Great start, keep in mind that the overall performance in the end will be about the whole bike . Brakes, tires, suspension , all those little adjustments with you in tune is what will make the ride ! :bike:
 
Hey Collin,
Welcome to the site. You'll find everything you'll need here in advice.
I got my '80 in similar condition. Just returned from Acadia National Park, Maine. What a great place to ride.
Good luck with the project.
Please make sure everything is hunky dory with the bike before putting it on a dyno. The dyno process will superstress the engine. First fix the sump screen which will likely be torn, and clean the oil screen behind the right hand case. Fresh oil, everything adjusted correctly on the engine.
 
YamadudeXS650C said:
Hey Collin,
Welcome to the site. You'll find everything you'll need here in advice.
I got my '80 in similar condition. Just returned from Acadia National Park, Maine. What a great place to ride.
Good luck with the project.
Please make sure everything is hunky dory with the bike before putting it on a dyno. The dyno process will superstress the engine. First fix the sump screen which will likely be torn, and clean the oil screen behind the right hand case. Fresh oil, everything adjusted correctly on the engine.
Click to expand...
I know yamadude i know. Ive worked on cars on the side of my "parts" job for awhile. I will check everything before a dyno run.
 
No, the G model didn't make 55 horse, and anyway Yamaha's numbers were gross power measured at the crank, not net power measured at the wheel. If you want to know if the motor is healthy, do a leak down test. That will tell you how well rings and valves are sealing, and that's about as much as you need to know about stock engine condition when it comes to making power. Consider putting some miles on the motor first to let the rings bed back in. If you want to do a dyno run just for shits 'n' grins, don't do it on a rear tire you intend to keep riding on; the rolling road will tear it up.
 
I think the factory rated them at 50 hp, first couple years a bit higher at 53. But as Griz said, that was measured at the crank. At the rear wheel we're probably only getting low 40's, but I think it's adequate. I feel this bike has enough power to make it fun to ride, enough for highway use (although all day interstate cruising isn't it's thing).

Funny you should mention that 883 Sportster. My buddy bought a brand new one years ago and let me ride it. He asked me what I thought and I replied "Honestly, it reminds me of the 350 Honda I had in high school ....". He didn't like that but it really was true. That thing was gutless for such a large displacement.
 
To beat a 883 is like racing a girl on a bicycle lol. If an XS can't , thats a concern.. Tho its fun to watch dyno testing, I would watch the others and not put my own XS thru the stress. I encourage you to seek a state of tune that is smooth through the rpm range and reliable to ride and sounds good ! Back to Dyno testing, If you really want to participate, I think it would be fun to tune a large bore 2 stroke to watch. That would be quick & easy to tear down , experiment with, and impressive to rev high and see the numbers !
 
batedpigeon79 said:
Thanks for the advise timemachine. I plan on checking out my local yamaha store and my other local powersports store. Once i get here done and ready to ride im gonna take her to the powersports dyno in town and see what she makes for power as far as health goes. I believe the 80 made 55hp so my goal is that possibly more if i can tune the carbs well enough and open the exhaust a little bit.
Click to expand...

Hi 'pidge,
don't sweat the max HP numbers because almost all of your riding will be at half-power or less.
I'd advise that you tune for a nice idle, an easy pickup and a responsive mid-range;
unless your engine is totally sucked out it'll have power enough.
 
Yes, this motor produces wonderful midrange power and that's one of the main things that makes them so nice. You don't have to run up to near redline going through the gears to have fun and enjoy the bike. It will pull and perform quite nicely with medium to big handfuls of throttle running the motor up to 5 or 5.5K through the gears.
 
Thanks for the advise guys. Ive ruled out the dyno the. Ill just get her to run really good and hopefully she will sound nice with just taking the baffles out
 
I've got an '80 SG. You have the G model. the biggest difference is the Mag wheels, rear disc brake and minor wireing. These bike are great back roads riding. Proper suspension and motor in decent tune, you will have all the power you need. Enjoy the scenery. Sure, you can sink a TON of $$$ in her with 750cc kits, Delorto carbs Megacams, Racetune forks and rear shocks or go single rear shock. For now, get her rideable. Maybe later better rear shocks. Minton mod the front forks when you reseal the front forks. Put a XS1 cam in when the top end is done. Other mods as needed. You will find even working on her is a joy. At least I do. Happy wrenching and rideing!
 
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Advertised horsepower didn't mean much back in the day; we used to say that those Japanese horses were pretty small. With the XS650 in particular, a lot depended on just how well the individual motor turned out; it was a price point bike from start to finish, the most cc.'s for the dollar on the market, and quality was pretty uneven. Some cylinder heads, for example, came out of the factory with ports that flowed a lot better than others, some cranks were very true and others not so much, etc.
 
Your bike looks to be in about the same starting point as my 78.It will be interesting to see how they come out.Mine had the rototiller bars when it was made but when i got it it now has dragstyle bars.For me it makes me lean too far forward and puts noneeded pressure on the wrists.I am only 5 foot 9,average height.I dont have any signal lights or sidecovers.if you have no missing parts be thankful.I hope you have brakes too.Mine are frozen,not working at all.Good luck.I was buying stuff off ebay.Sometimes that is my only option.But also here in the classifieds there are many members that have what you might need.i have found several of these bikes in very nice condition for 2000 to 3000.I could easily buy one.But I do this for fun and learning.I have a nice daily rider honda so time isnt an issue.Read the history of the xs if you havent already may i suggest.These bikes out bonevilled the bonneville.
 

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