XJ Horsepower

I just went through this with my 2 uncles, one bought a 2002 1100 Shadow (60 HP) and the other bought a 2005 650 V-Star (30 HP), and they were amazed that my 81 650 Maxim blew them away (70+ HP) I on the other hand sat back at the finish line and laughed

 

Woah this thread has been around for awhile.

It made me wonder after hearing about the power of some of these cruisers when their owners are shocked at the power of an XJ. Surely they must be aware that there are 600cc sport bikes producing 115hp or more? And if not they must be really out of touch.

 

My son has a V-Twin bike and when we ride together,... say at about 40 mph, he can just twist up some acceleration....RIGHT NOW.

I on the other hand have to drop a gear or two to accelerate at the same speed.

But he still envys the smooth sound of that inline 4!
He also cant believe the way a 700 shoots right by his big 1100

 

The last page of this linkhas the HP and Torque curves for an '80 XJ650. It shows a max RW power of about 48 HP so I'm not sure how accurate it is (not corrected, etc.) compared to the advertised 90+ HP, but will get you in the ballpark of what you are looking for.

 

Actually H2 's have "reasonable" fuel consumption Wayyy better than an Escalade for example.
Big Bore Bikes are for Big Fat lazy guys Or so it seems by observation. Looking good is the intent, going fast is neither a requirement nor desired.
Younger son's Brand New Honda 600RR aledgedly outputs 118 hp.. 108 of which actually make it to the ground, at 370 lbs 'Quick' is an inadequate descriptor.
But I wouldn't wanna spend hours at a time on it.
Different horses for different courses.

 

Whats the hp rating of my 1985 xj700n maxim?

 

I belive the 85 700 ran 86hp @9500rpm/ 49.9 ftlbs torque and mid to high 11's 1/4 mile around 112mph but keep in mind that these aren't new bikes anymore most of us are running twenty year plus bikes, I don't know if anyone took the time/money to accually dyno one but with various wear, compression etc i can't help but doubt that all these bikes still do what they once did! however i do believe especially for there time the xj line up was pretty impressive and enough so to still keep up twenty some years later!~

Shaun

 

A LOT of our XJs are very low mileage bikes and once gone through run just like new. It's really fun having a virtually new 27-year old bike.

 

hey fitz I'm not bagging on it i love my max but at 16000km's and 27 very likely neglected years i think a part even if just a small part of her get up and go... well... got up and went! and i doubt mine is the only one

 

Well boys, my old Max will turn 100,000 kms this year (61,000 miles) and even with everything driving it except tires original, she still runs like hell. Helli-good that is. Not sure what this translates to in HP, but all I can say is that there is still plenty of acceleration, more than enough for me to believe in the 71hp claimed by Yamaha. More unknowing riders have scoffed at my "little 650" and get impressed by the big bike sound and guts.

This whole generation and similar offerings from Honda, Kawasaki and Suzuki all exceed expectations and I still wonder why no one makes anything similar today, or why the style died away. Great bikes! I guess this budget exclusivity appeals to me and through time, will only become more so.

 

power and torque are two weird things, you'd think they would go hand in hand, but they dont,really, diesels are low hp, but crazy torque, i bet you culd hook a 70 hp tractor to the back end of my dads new 6.0 chevy, with probably 5 times the hp, and out pull it, just cuz of the weight and torque, and traction.... idk, but yup looks like we figured it out

 

i guess I'll have to see once i get all the work done maybe mine will get it's jam back!

 

Thanks for the info xj650ss.

 

glad I could help

 

I know a couple years back I took my 650 maxim to Englishtown, NJ Raceway Park and ran against a brand new V-Star 650 and smoked him! Needless to say he was a little hot since I picked my bike up on ebay for $750. It was awesome!


:lol:
:wink:

 

You can work out what your "real world hp" is if you know the 1/4 mile time your bike "does" (not did ) your trap speed, and the total weight of bike with everything as is when it did the time (rider helmet fuel.. and so on).

It simply breaks down as newton second law of motion.

Second law
Observed from an inertial reference frame, the net force on a particle of constant mass is proportional to the time rate of change of its linear momentum: F = d(mv)/dt. This law is often stated as, "Force equals mass times acceleration (F = ma)": the net force on an object is equal to the mass of the object multiplied by its acceleration.


Here is a calculator to work it out, plus some other handy stuff.

http://www.cprparts.com/HPcalculator.html

 

Flash4, doesn't your equation assume linear acceleration? There will be shifts, reaction times, wind, etc. that will cause errors.


It would seem to me that the only way to accurately determine BHP would be to dyno the bike. I'm pretty sure that my liver would fall out if I ever put my bike on a dyno as any exposure I've had to this process it looks like they just flog the bejeebers out of the engine.

 

Actually the only way to 100% acquire a engines h/p is on an engine dyno. Rolling dynos have to many "adjustments" and "theoreticals" to be spot on. Dyno's are a great tool, but for tuning only, not for measuring h/p.

Although you are some what correct with your statement.

As i stated this is to work out "real world h/p". This takes in factors that a dyno could never reproduce. Such as aerodynamic drag, gear shifts, the weight of the vehicle and so on.

Of course reaction time will disguise a minor amount of this figure but it will be minor. You could always just minus the reaction time from the trap time anyway.

This is how it compares to a dyno:

Say you run you bike standard and it does a 12. You put on a 4-1 and run it again. This time you get a 11.6. Jump to the website with the calculator and put in you original time and speed and weight, then put in the new figures. You have lost weight and have gained speed and lost time. This would work out to a h/p increase of say 20hp. The dyno would tell you you gain 10, but what about the weight loss? You have actually gained more than just the hp, the dyno won't tell you that.

It all comes down to: Force = mass x acceleration.

 

I see what your saying Flash, but the big question - What do our bikes weigh? Anybody?

 

Check your service manual. That's how I know claimed dry weight for the 550 Seca is 407lb.