View Full Version : Any tricks to squeeze out some more speed

03-11-2006, 12:03 AM
Does any one know of any tricks to get some more speed out of 48tthp 17kaw? After demoing a ZTR it seems that my tthp has slowed down:laugh:.

03-11-2006, 12:38 AM
Make sure your RPM's are set correctly.

At least 3750 free load.

03-11-2006, 12:48 AM
Make sure your RPM's are set correctly.

At least 3750 free load.
the gauge on it reads about 3580. but I don't know how accurate it is , I'll check it with my Fluke Multi Meter. Thanks TLS

03-11-2006, 12:50 AM
Thats low...crank em up!:cool2:

03-11-2006, 12:58 AM
I'll do that. How would I check the linkage adjustment to see if it is set properly?

03-11-2006, 01:02 AM
I don't understand your question.

If its taching out at 3580, it ISN'T set properly. You'll need to adjust it.

Most Kawi's high speed adjustment involves loosening the throttle brackets at the carb and pulling the entire bracket tighter.

I don't know if your Kawi is like my 14hp or my 27hp.

Make sure you have a new spark plug, airfilter, and fuel filter installed prior to setting RPM's.

03-11-2006, 01:13 AM
I'll do that. How would I check the linkage adjustment to see if it is set properly?
Sorry, I wasn't clear on that. I am referring to the hydro linkage adjustment. I understand the throttle adjustment, thanks. How often should I replace the spark plugs? I pulled them out at 200 hrs and they looked great. I now have 225 hrs on it. Probably should go ahead and replace them huh?

03-11-2006, 02:24 AM
the thing you have to watch out for when adjusting the linkage on the tthp is that you dont go too far b/c then you wont have reverse .

03-11-2006, 02:37 AM
check your throttle cable and make sure its not sliding where it attaches to the engine. Mine worked lose and lost rpms.

03-11-2006, 03:06 AM
- pwner snip -

03-11-2006, 10:51 AM
Buy a ZTR.


03-11-2006, 12:47 PM
Buy a ZTR.

I didn't say how can I make it run with a ZTR. I knew that some smart arse was going to say this.:hammerhead: Gee, why didn't I think of that?:dizzy: Your a real genius. Lets see, adjust a few things on my WB and maybe spend a few bucks, or spend $10,000 for a ZTR. Not that I wouldn't like to have ZTR also but I can't justify spending that at this point, maybe later this season or next. Thanks for your time Oldtimer.:waving:

03-11-2006, 01:06 PM
With ECS system, your max speed is @ 6 mph set at 6 speed, you can rig your kawi and increase tire pressure or use lighter sulky BUT you will not go faster than 6.5 mph cause the design and pump that eXmark use. It is the drawback of WB in comparison to a Z, if eXmark can improve speed to at least 8.5 mph like Gravely and Stander, they will be hot cake BUT engineers at eXmark come with answer..."safety issue" No need for us to do any speed improvement. end of game. They say WB is WB not rider, if you want fast you have to pay for a Z. Comprendez

03-11-2006, 01:29 PM
It really has slowed down from when I first got it, not a lot but I can tell. TLS pointed me in the right direction to get it back up to par. Thanks TLS :clapping: The dealer raised the tire pressures and measured the circumferences and it felt like it had wooden wheels on it. Then I checked it after them and they had almost 45psi in them. I lowered it back down to the recommended tire pressure 12-16psi. I think it was there quick fix to get the speed back.

04-08-2006, 02:12 AM
I went by the dealer the other day and they adjusted the RPM's up to 3650 with no load. They said that 3750 would be too high. The factory manual says 3600 max no load. At 3650 it seems like it is as fast as it ever was when it was new. Would another 100 RPM make that much difference, and would it increase BTS?

04-08-2006, 06:38 AM
I wouldn't worry about that extra 100 RPM. Not on a walkbehind anyway.

But keep in mind, eXmark sets their Lazers rpm's at 3750 from the factory.

04-08-2006, 03:13 PM
Kawis run okay at 3800 rpm. The thing to watch though is the hydros as Hydro-Gear recommends a maximum input speed of 3600 rpm. Speeding the engine passed the manufacturer's recommended speed most likely will over speed the hydros. Over-speeding the hydros will decrease the bearing life, but I agree with TLS, I wouldn't worry about an extra 100 rpm.

04-08-2006, 03:35 PM
Crank em up to 3750 like TLS had said, you'll see a big difference with 100 rpm increase. One thing to watch with the Kawasakis is oil pressure, on my 25hp Kawis, the low oil pressure light will come on if the rpms get over 3800. I guess it can't pick up oil properly with them that high.

04-08-2006, 04:52 PM
Another issue could be blade tip speeed.

3800 rpms would result in a blade tip speed of >19,500 fps if my math is correct. Would someone check my math please?


04-08-2006, 11:34 PM
It seems to be just fine at 3650. I don't think I would want it to run any faster. Thanks guys!!:clapping:

04-09-2006, 02:15 AM
Flying over the T-bar even at 6+ mph is a pita, I would hate to see what happens at 8.5 +
Just the other day I hit a mound of dirt and yup, humped the ole' girl... It all happens so fast, I'm so used to it that I wasn't even thinking, just put my hand out to stop myself and of course, the hand rests on the muffler. Minor 2nd degree burns, a first-aid kit, some motrin (1800 mg's) and PAIN for 20-30 minutes but I was able to continue working.

Yes: Serious injury and even death can happen.
You have been warned.

To increase the speed of a belt-drive Wb, you'll need to change one or the other transmission-belt driver pulleys. It works like on a bicycle, the larger the pulley in front vs. the smaller the one in back, the faster you will go.
A small change in size makes a big difference, to get the right pulley you will likely need to get in touch with some lawn mower racing folks as they will likely be able to provide you with a racing pulley for your machine. Keep in mind machines such as these are capable of top speeds of 40 - 50 mph so you'll need only the slightest change in pulley size: Pull both pulleys off and measure them, you will want the measure of both because it will be easier to find one OR the other.

You will need to carefully measure clearances to make sure the new pulley will fit before they send it. Get the size of the pulley, etc, etc...

In addition, be aware the transmission belt size may change by an inch or so, Napa belts can compensate for this.

Once re-assembled, you'll need to tweak other settings until you get it to not skip blades of grass. The faster the machine, the more it will skip and miss. True racing mowers don't cut grass, they race, yes, literally, on a track.

How to do this (or whether you can do it) with a Hydro, I do not know.
Whether I would ever do this that is another story, but I think about it a lot.
h3ll yeah cut grass at 30 mph LOFL !!! (you'd hurt yourself guaranteed, recommend a really minor adjustment).