GT750 dyno info

Arne · Post by **Arne** » Tue Jan 13, 2009 10:19 pm

I figured I'd throw up what I could find on different GT750 that were claimed to be dyno'd and see if there was any correlation to what you folks have been seeing.

Youtube guy
110.5 to the wheel
http://www.youtube.com/watch?v=al0Io2StBLI

Youtube guy in comments to previous video with a 850cc ocelot engine
125 ?at the crank?

Youtube guy from the USA2strokers board with allspeed chambers on
69.2 to the wheel
http://www.youtube.com/watch?v=IEGPnEsd ... re=channel

Youtube TR750 on dyno
118 to 122 ?at the crank?
http://www.youtube.com/watch?v=DcQzWufTb9E

Ocelot made two basic race engine types:
http://dsr.racer.net/engines/suzuki/gt750/page1.htm

A 750cc "regional" engine good for
110-115 HP at the crank
A 1978 pricing sheet from Ocelot shows the "Introductory" 750cc engine at $2,463

Their killer 850cc
130HP at the crank
"national" engine. The same 1978 pricing sheet from Ocelot shows the "National" 850cc engine at $3,545.

GT750 Stock
67 hp at the crank
http://www.motorcyclespecs.co.za/model/ ... 0%2077.htm

Waterbuffalo possessed guy
105 at the crank
http://smokeriders.com/Technical/Suzuki ... ocket.html

TR750
107 to 109 HP at the crank
http://dsr.racer.net/engines/suzuki/gt750/page1.htm
http://www.thekettleclub.org.uk/tr750/tr750.htm

Kettle club
http://www.thekettleclub.org.uk/suzukig ... lution.htm

Measured bhp at rear wheel tests. The first two sets have been chosen 'cos they are the only tests I can find to show the relative difference in performance between J-K-L and M-A-B measured on the same equipment. Both sets of figures are taken from American magazine CYCLE GUIDE and have the following note attached.

The third column is taken from a dynotest done 2 years ago on an 'A' fitted with Micron 3 into 3 spannies. You should not draw a conclusion that the spannies give extra 6bhp because the testing machines are different. What it does show is the movement of improved power towards top end and the very rapid drop off over 7000rpm.

The figures for horse power delivered to the ground are as measured by a Patraco Mklll rear wheel dynamometer. These figures may vary from the manufactures' claims , or from those obtained on a different dynamometer .

RPM 'L' bhp May '75 'M' bhp August '75
My model 'A' with 'original' Allspeeds

2000 9.5 5.50 6.00
2500 13.6 7.10 11.00
3000 17.60 11.10 14.50
3500 23.80 18.50 17.00
4000 29.40 24.90 24.00
4500 33.10 31.30 27.50
5000 36.50 37.00 32.00
5500 38.00 45.40 44.50
6000 38.80 48.50 53.50
6500 38.60 48.00 56.00
7000 37.80 45.00 50.00
7500 36.10 38.60 38.00
8000 30.20 30.00 30.00

Jollymoto exhaust
70HP ?at the crank?
http://www.50cc.nl/2stroke_pleasure.htm ... asp~TsMain

Saxon GT750
125 rear wheel
http://www.ozebook.com/compendium/gt750 ... icles.html

That's all that I can find off the internet. I know a few of you guys have run your bikes on the dynos...

Anybody care to post add'l info? Thanks - Arne

tz375 · Post by **tz375** » Wed Jan 14, 2009 10:52 am

Arne, Nice research.

I suspect that the reason we don't see a lot of dyno charts is because most people discover that their bikes don't make nearly as much power as they had hoped for.

All the manufacturers claims can be heavily discounted too.

The comparison between the L and M was amazing though. So much more bottom end on an L and so little top end. Even the 70hp M only made 49 in the real world.

On the kettle club site they had a before and after chart with a set of Gibson/allspeeds and it went from about 48 to about 55 if I recall correctly.

The first of those Utube videos is Shannon in Sydney, and the second was Alan Pulsifier whose motor was gently reworked by Scott Clough and it had Jemco chambers.

The highest dyno figure I have seen so far I think came from Gary Ryder at about 81ish.

Of course the guys with mega HP maybe don't want everyone beating a path to their doors and may just be keeping quiet.

My last A was ported and had a high comp but I never put it on a dyno. I guess I'll have to spend some time on the dyno with the two projects I'm working on and then at least I'll know

Post by **Suzsmokeyallan** » Wed Jan 14, 2009 12:01 pm

Then theres Suzukidaves project bike, now im waiting ever so patiently to see what this motor produces,,,,,,
The mechanical alterations look good on paper but the biggest benefit here is the FI with the ability to remap as needed...we shall see...
Has Dave found the magical key to unlocking more power from the Buffalo engine.
All things aside i wonder what a TR750 engine would do with the FI system on it.....

tz375 · Post by **tz375** » Wed Jan 14, 2009 4:11 pm

Dave's motor should make more power over a wider powerband than any other GT750 ever in the history of mankind. FI and reeds will help clean up and fatten the lower to mid revs and will work with the porting to make an equally fat top end.

So there's no pressure there Dave.

EFI doesn't really make any more power. What it does, is allow for easy "jetting" changes and the finer atomization potentially will improve fuel economy and emissions which is very socially responsible, but doesn't make much difference on a dyno. In theory, smaller droplets and better vaporization should make for a more complete burn using less fuel, but that does not necessarily mean more power.

As for EFI on a TR, well it's all conjecture, but I don't think it would make a great deal of difference on its own. They were more limited by lack of port area than by carburation. A programmable ignition might have had more impact on the powerband and modern pipes might have helped, but a new head would probably have been a better start along with more transfer area and lower port velocities. As I said before, it's all conjecture, so feel free to imagine..

rngdng · Post by **rngdng** » Wed Jan 14, 2009 7:39 pm

BlueBoy did 80 at the rear wheel. I was told that on a Dyna-jet dyno, it would have pulled more.

Lane

tz375 · Post by **tz375** » Wed Jan 14, 2009 10:06 pm

Lane,
That's pretty impressive. Was that with the BS40's or the roundslides?

What was the power/torque like lower down in the powerband c/w stock? In other words did you make a huge sacrifice at the bottom to get more up top or did you manage to salvage some of the lower end.

Suzukidave · Post by **Suzukidave** » Sat Jan 17, 2009 9:31 am

M dyno run with All Speeds .

Suzukidave · Post by **Suzukidave** » Sat Jan 17, 2009 9:38 am

http://www.youtube.com/watch?v=IEGPnEsd ... re=channel with Jemco pipes . Scott Clough porting

Arne · Post by **Arne** » Sat Jan 17, 2009 7:29 pm

Here's the deal with motorcycle dyno's:

http://www.triplezeecycles.co.nz/DynoTu ... mpare.html

Go down about half way to the TRUE HP on this page:

http://www.factorypro.com/

So basically if you put it on a dyno jet you get 15 to 20 percent high reading because they put in correction factors for chain, transmission loss, etc; put it on the other kinds of dynos you get the rear wheel horse power.

Arne · Post by **Arne** » Sun Jan 18, 2009 5:09 pm

Suzuki's race chief, Ishikawa, when asked about horsepower, "More than 90, less than 100."

http://www.3cyl.com/~mraxl/gt/articles/ ... lerup1.htm

tz375 · Post by **tz375** » Sun Jan 18, 2009 9:49 pm

..and that was at the crank and probably adjusted for losses at the waterpump , oil pump and ignition.

Dave, those graphs of stock and with Alspeeds(Gibson) look about right.
I want about 80 at the rear wheel with a huge fat powerband starting just off idle and ending at 6500. I suspect that may be just outside the grasp of reality.

Suzukidave · Post by **Suzukidave** » Sun Jan 18, 2009 10:22 pm

Maybe not with the reed intakes

tz375 · Post by **tz375** » Mon Jan 19, 2009 12:11 am

That's OK for you to say

, but I didn't plan on a big buck reed conversion on the el cheapo Phat Trakka.

I was thinking 34mm TMX flats, high compression (155psi+), modest port timings with wide ports for extra time/area and a little more ignition advance than might otherwise be sane for that sharp throttle response and explosive acceleration off the line.

If I go too far, it will be exploding under acceleration...

For the FZR600R/R7/GSXR/GT750 hybrid, I want reeds, squish heads, 38mm EFI and a much bigger top end hit, but for the Trakka I want it to pull like a train as a street Hot Rod geared for say 100 at 6,500. No need for big numbers at high rpm on this one.

Suzukidave · Post by **Suzukidave** » Mon Jan 19, 2009 7:19 am

Cool .. this bike sounds like the perfect Deals Gap Bike .. hint, hint

tz375 · Post by **tz375** » Mon Jan 19, 2009 11:25 am

I was idly whiling away the time, as you do, reading Performing Berks magazine and chanced upon the dyno charts for Kawasaki ZX10R that they were modifying to get more midrange.

At 6,000 it was making about 70 RWHP and by 7k it was up to about ninety - almost the same as a good TR750 right? Well, the graph just kept on keeping on until it peaked at about 160 horses at 12,000

Talk about a reality check

But if 80 HP can drag a bike along at 170 per at a soulless place like Daytona, and the speed limit is 55 in the US and 65-75 elsewhere, WTF does anyone do with the surplus 100HP?