Q&A Forum
Hello All.
I've had this old Patraco water brake bike dyno for 20+ years never had time to mess with it. At some point in its life, the heat exchanger was frozen and burst. Most of the plumbing was cut or disconnected as were the wires. I'm struggling to figure out how this worked as it was originally plumbed most of the water would have recirculated in the heat exchanger so how would it add pressure to the inlet side.
It looks like as originally designed the water was just sent to drain, No tank.
At this point I don't care about measuring the load I just need to put a load on a bike to check the jetting. Normally I go to a good shop but there down waiting for parts and my 2nd choose guy says he's got no time and "it's to cold"
My brake has two 3/4 hose barbs on one side one nearest the shaft (Suction I believe) and one closer to the OD (outlet) and then 180 geg on the housing there's a 3/8 fitting with Tee that has a check valve to air (no connection) and a 3/8 hose barb that runs to an adjustable pressure valve hat i think when to the suction side.
I've got some pictures but no place to host them currently.
So I'm looking for some basic plumbing diagram to give me some load. I read that it needs 70psi on the suction side of the break but not sure on the GPM i'll need.
Thanks for the help.
44Dwarf
Hi 44Dwarf, Welcome to the forum 44Dwarf , you can post pictures directly here on the forum.
Post some pictures on the forum , you can control the inlet , or the outlet or both simultaneously. Do you have any water valve(s) at all that come with the dyno ?
Here is a visual example for plumbing up a water brake dyno on YouTube
Tech Talk Animation on How Water Brakes Work
Down the bottom of this box , can you see " Attach file"
No such Box on my page. 🙁 forum must have min post before i'm allowed to add photos.
The longer of the two pipes into the heat exchange goes to the inlet side of the brake (closest to the shaft) judging by the hose length.
The small 3/8 hose looks to have been run from the brake to a 20psi 1/4 pipe bleed valve.
Hi, I would just drop that heat exchanger for now. A heat exchanger is necessary if you run long runs in a closed loop. We do not use a heat exchanger in our setup, we just let the water go to the drain.
How much horsepower are you going to test/what is the brake rated for? If it is low, you can try to just connect it to the house water and control the flow with a manual valve. Make sure to adjust the output valve so the flow is not too fast or too slow (you need to experiment). You may quickly find that you need a pump, but I would test it first like that to get a feel for its operation.
That's my plan, for now, ran new hose tonight with two ball valves.
I have a small 10gal tank with an unknow flow rate pump I'm going to try.
100hp and 150mph IF it was rated at full gauge readings. The model number tag it 90% missing.
The bike I need to run under load should be around 53-60hp. it previously made 58hp with smaller valve head and smaller cam but not to concerned with the number but it felt lean mid throttle after a jetting change last summer it had been rich there in the past to the point it would 8 stroke if the weather was right / wrong.
500cc single cyl Rotax 89.5mm bore 81mm stroke.
The drums have a roll-out of 28.5 inches.
Thanks, I'm hoping once I get it sorted to use the package available here and get it modernized. I pray the seals are good in the brake as I'm out of time for testing.
One thing that i find odd as seen in the pictures is a 1/4 NPT spring loaded check valve with no connection. My thought was that it may have been to aid in draining the brake unit for winter as it looks like this may have been run with city water originally? I plan on RV anti freeze for this test and a larger glycol tank with a radiator or a small chiller IF the brake works.
The spring loaded check valve may indeed be for draining.
Well, it works! I can apply more load then my Sticky Flat tracker tire will hold. It was a bit of a trial an error to get the manual valves adjusted to load it enough so when wheel speed got up there it would not smoke the tire or stall the motor.
My wife snuck out to hear it and shoot this. It was very lean down low like in the 18's a pilot change and needle adjustment after this run made a world of difference
https://www.facebook.com/janehl/videos/10221907057694567/
Not sure if this is video veiwable by the public or not.
Nice to hear! I cannot see the video, can you upload to youtube or somewhere?
I will try to get her to e-mail it to me so I can post it.
I did this walk around afterward. Sorry, no running bike in this one.