Dyno'd an 83 gs750es today.. RESULTS.. decent? good? so-so?

[Anonymous]

Took the bike for a dyno run this morning, and after hooking everything up, it showed that it was running very lean at low rpm's / idle, but once it was on full throttle it seemed to be running better... Off the dyno runs, I have a very flat tq curve starting at about 3k RPM about 15tq and 26 HP. TQ goes to its first peak at 5200RPM at 35TQ takes a little dipof about 1 or 2 TQ stays there for 500RPMs, then goes back up to 40.7 TQ at 6800 then stays at 40.7 until 9400RPM's then drops back down a bit...
Horsepowerstarts at the 26HP at 3k, goes up to 36HP at 4k, stays flat until 5500 and at 6k shoots up very evenly to 70.4HP(MAX) at 9k and stays flat until 11k. Has anyone else done a dyno on their bike? How does mine sound? As far as I know, everything is stock.

[SqDancerLynn1]

Sounds Ok GS850 is rated at 70 HP as a comparason

[Billy Ricks]

Should be peaking somewhere around 80hp.

[oldschoolGS]

bone stock numbers should be roughly- 87ihp(crank) and 76bhp(rear wheel). Ride on, Ed.

[zstanisi]

bone stock numbers should be roughly- 87ihp(crank) and 76bhp(rear wheel). Ride on, Ed.

Really? Where did you get the info from, I searched around and only thing I found on internet was 72hp? I've got 83 GS750ES.

[Anonymous]

bone stock numbers should be roughly- 87ihp(crank) and 76bhp(rear wheel). Ride on, Ed.

Really? Where did you get the info from, I searched around and only thing I found on internet was 72hp? I've got 83 GS750ES.

Output numbers can be confusing since it depends on where they are measured. Manufacturers quote "crankshaft" numbers, measured before driveline losses (10 - 15%) are taken into consideration. Most magazines today use rear wheel numbers, measures by a dyno........and different dynos under different conditions can produce different numbers. However, dyno measurements are "real world" numbers in that they measure what hp and torque is available for application to the road. I seem to remember Suzuki's spec "crankshaft" hp for the '83 GS750E/ES was about 84 hp, which would imply a rear wheel hp of about 72 - 76 hp.

[Anonymous]

I just located a Cycle magazine review of June 1983 for the '83 GS750ES. Rear wheel dyno numbers are quoted at:

Max hp = 72.27 @ 9500 rpm
Max torque = 42.36 8500 rpm

The review article has the outputs for the entire usable rev range, and does show a torque "plateau" of about 35.5 lb-ft between 4250 and 5750 rpms, before resuming the climb to the max torque at 8500 rpms.

Simon

[zstanisi]

Thanks Simon, it's nice to know.

[oldschoolGS]

I had most of the original literature on this bike as I am the original owner of my 83 750ED. 87IHP was the published figure then, but remember IHP is crank power, BHP is rear wheel power-you usually lose about 10-12% thru the tranny and drivetrain which should give about 76BHP. The article on Yoshimura's race preped 83 GS750E profiled in Jan. 1984 MOTORCYCLIST stated the bike pumped out app. 76BHP stock and app 90BHP with their mods. I have also seen two stock identical bikes vary up to 5% in power output due to factory assembly differences. Whatever the case it is just a number, if your bike runs smooth and pulls hard thru all gears I would not worry about it. Ride On, Ed.

[Anonymous]

I had most of the original literature on this bike as I am the original owner of my 83 750ED.......Ride On, Ed.

I am an original owner, too, but my wife accidentally threw out all my bike mag reviews many years ago. I have managed to find a couple of old articles again but my bike folder is sadly depleted. I do still have the original 4-page color sales brochure for the 1983 GS750E/ES, though. You've got it just right, Ed: Ride On!!

[oldschoolGS]

Simon, very nice original bike. Mine was an original blue/silver E model. I bought it new, left over in late 1984 for $3000, last one on the floor. Everyone was waiting for the 85 GSXR to see if it was to be sold in the US and therefore uninterested in my E model. What a scoop it was, if only I had scooped that Limited Edition 86 GSXR750 that sat at the same dealer for months. Anyway the E sure is a keeper. Ride On, Ed.